Pedestrian Safety in Compact and Mixed-Use Urban Environments: Evaluation of 5D Measures on Pedestrian Crashes

: This study examined the impact of density, diversity, design, distance to transit, and destination accessibility, ﬁve measures, known as the 5Ds, that characterize the built environment, on pedestrian–vehicle crashes in Seoul, Korea. Using spatial analysis based on 500-m grid cells, this study employed negative binomial regression models on the frequencies of three speciﬁc types of pedestrian–vehicle crashes: crashes causing death, major injury, and minor injury to pedestrians. Analysis shows that compact and mixed-use urban environments represented by 5D measures have mixed effects on pedestrian safety. Trade-off effects are found between a higher risk for all types of pedestrian crashes, and a lower risk for fatal pedestrian crashes in 5D urban environments. As a design variable, a higher number of intersections is more likely to increase some types of pedestrian crashes, including fatal crashes, a ﬁnding which warrants policy attention to promote pedestrian safety near intersection areas. This study also conﬁrms an urgent need to secure the travel safety of pedestrians near public transit stations due to the higher risk of pedestrian crashes near such facilities. Various destinations, such as retail stores, traditional markets, and hospitals, are associated with pedestrian crashes. Pedestrian safety measures should be implemented to reduce the likelihood of pedestrian crashes near major destination facilities.

Introduction
From the discourse on how to resolve transportation problems in Western cities, particularly the car-oriented cities of the United States (US), the concept of compact development has emerged. Since the late twentieth century, the vicious cycle of automobile-dependent transport systems and urban sprawl has led transportation planners and policymakers to frame a progressive concept of smart growth by promoting high-density and compact development in US cities. More recently, certain cities in Europe, Asia, and Africa with heavy traffic congestion and degrading environments have made the discourse on compact development even more important [1][2][3][4].
Though measures to design and implement compact urban development and environmental improvements have been diverse, they mainly aim to adopt high-density planning and efficient land-use. Such measures invariably address the "five Ds" (5Ds) of the urban built environment: density, diversity, design, distance to transit, and destination accessibility [5,6]. Some previous research indicates the potential of compact urban development for improving traffic safety by creating pedestrian-friendly urban environments, and promoting high urban density and mixed land-use [7][8][9]. For instance, planning strategies to reduce automobile dependence, and increase walking and biking, facilitate mixed land-use and job-housing balance, thereby lowering pedestrian-vehicle crash rates in urban environments [8]. In contrast, urban sprawl is related to higher numbers of traffic fatalities [10].
However, compact and mixed-use development may increase the frequency of vehiclepedestrian crashes by increasing the volume of pedestrians in more compact and mixed-use urban environments [11]. In other words, as the number of pedestrians on roads increases, the potential risk exposure of pedestrians to traffic accidents may increase, despite there being less automobile travel [12]. For instance, one study [13] identifies that the number of pedestrian-involved crashes increased in counties with a high proportion of people whose primary travel mode is walking (the US and Italy). Furthermore, another study reports an increasing number of pedestrian-vehicle crashes as urban density increased, despite the opposite relationship between pedestrian fatality rates and urban density [14,15]. These results imply that higher density is associated with the possibility of a higher number of traffic accidents (due to increased risk for pedestrians), but that the higher density may lower the occurrence of pedestrian fatalities through other channels in dense urban environments, such as lowering traffic speeds [16]. These complex and mixed findings can increase concerns about the role of physical environments in promoting physical activity [17].
This line of recent research implies an urgent need for empirical validation and exploration to further refine the complex relationships between compact urban environments and pedestrian-vehicle crashes, especially by analyzing more diverse urban contexts. This is the primary motivation of our study. This study examines how urban built environments influence pedestrian safety by analyzing pedestrian injuries in a highly dense and mixeduse Asian city, Seoul, Korea. More specifically, this study examines relationships between pedestrian-vehicle crashes and various measures of urban developments, based on 500-m grid cells as the spatial analytical unit. Furthermore, this study investigates relationships according to different severities of pedestrian injuries and fatalities caused by accidents between pedestrians and cars in the urban environment.
Despite numerous studies reporting the benefits of 5D compact development, its impacts on transportation safety have been less clearly identified [33][34][35]. A reduction in traffic accidents has been traditionally addressed by focusing on observed improvement in the geometric structures of road segments and traffic crash hotspots. These "traditional" and post-prescription approaches, however, are considered neither optimal nor preventive insofar as they are reactive, following traffic accidents that have already occurred [36]. Another new approach focuses on the prevention of traffic accidents by decreasing the total travel demand, and changing the travel patterns of vehicles, such as trip frequency, mode choice, and travel distance. Fundamentally, changes in travel patterns are heavily influenced by land-use patterns, density, and urban accessibility. This is where the relationships between transportation safety, urban environments, and development patterns promoting high-density and compact development become crucial.
Especially when pedestrians are involved, efforts to reduce traffic volume and alleviate traffic problems by redefining urban environments impact the intensity of the risk for vehicle-pedestrian crashes, and moderate personal travel behaviors [37,38]. This so-called "population approach" aims to reduce vehicle travel on roadways by fundamentally restructuring urban built environments. In particular, traffic volume and vehicle speed are closely associated with urban 5D characteristics. Empirical evidence that supports compact urban development shows that mixed land-use, job-housing balance, and a reduction of automobile dependence lower traffic accidents, whereas urban sprawl is related to higher numbers of fatalities [10]. Overall, urban features to promote high-density environments, walking, and shorter durations of vehicle travel are expected to protect the safety of pedestrians exposed to vehicles in high-risk hotspots [7,9]. Nevertheless, conflicting evidence also exists [12,39]. For example, a higher volume of pedestrians in a more compact and denser environment increases the frequency of vehicle-pedestrian crashes [13]. Despite reduced vehicle travel, a higher number of pedestrians increases the potential risk of traffic crashes. In addition, one study [14] reports a higher number of pedestrian-vehicle crashes as urban density increased, whereas another study [15] finds that the pedestrian fatality rate was shown to decrease as urban density increased. For instance, retail employment density has been positively associated with pedestrian crashes in urban and rural areas [40]. Similarly, more pedestrian crashes have been found in commercial areas in Austin, Texas [41].
Overall, these results imply that higher density is associated with the possibility of more traffic accidents (due to increased risk commensurate with the increased number of pedestrians), but that higher density may lower the possibility of pedestrian fatalities, partly due to reduced vehicle speeds [42]. Another potential reason for conflicting findings on the relationship between the built environment and traffic safety is that the risk exposure for the traffic population might not be adequately measured [12]. For instance, different studies introduce different exposure units into their dependent variables by dividing traffic accidents by the number of residents [43], the land area [44], the number of traveling vehicles [45], or the vehicle kilometers traveled [46].
Land-use diversity can be another confounding factor in traffic safety. Greater land-use diversity has been shown to be negatively associated with pedestrian crash rates in Melbourne, Australia, which has comparatively more active transportation mode choices [47]. In contrast, land-use diversity has not been shown to consistently contribute to crash rates in the metro Detroit region of Michigan, USA [48]. One study reports that mixed land-use reduces the risk of pedestrian crashes for school-age children only in high-income neighborhoods, implying that greater land-use diversity does not necessarily promote pedestrian safety overall [49]. In addition, another study reports that greater mixed land-use was shown to be positively associated with an increased number of bicycle crashes in the San Francisco Bay area of California, USA [50]. These empirical studies suggest that land-use diversity might not be consistently associated with lowering crash rates.
Certain design measures seem to be closely related to pedestrian crashes. One study, for example, reports a belief among school-age children in a pedestrian crash risk due to the presence of crosswalks and more building entrances around intersections [51]. Another study finds that intersections with transit stops were positively associated with more pedestrian crashes [35]. In contrast, other research [38] shows that in Italy, road intersections have been proven to decrease the risk of pedestrian crashes (directly contradicting the results of other studies).
Transit access measures to promote pedestrian-friendly environments can also add unexpected costs that offset improved pedestrian safety [12]. Examining the causes of ward-level vehicle crashes in London, one study [52] finds that as the number of bus stops increased, the frequency of pedestrian crashes increased. Other studies report the same results, and demonstrate that intersections with transit stops have been shown to be positively associated with pedestrian crashes [46,53,54]. As a result, better transit accessibility tends to increase the frequency of pedestrian-vehicle crashes, despite encouraging people to walk and take public transit more often.
Destination accessibility, unlike the other 5D factors, is an index for which relatively few empirical studies have been conducted [12]. In TOD, facilities designed to enable passage near residential areas (that is, local accessibility) might be related to pedestrian crashes. For example, one study [55] reports that pedestrian-vehicle crashes in the city of Seattle in Washington, US, decreased as the distance from the city center increased, and in spots where there were no retail stores or neighborhood living facilities. In other words, that study shows that densely developed areas were more likely to be associated with a high frequency of pedestrian-vehicle crashes.
Indeed, the value of public transit and TOD can be undermined by perceived concerns about traffic safety [56]. Despite many benefits from TOD environments, concerns about its mixed effects on pedestrian safety can impede the successful adoption of TOD and pedestrian-friendly environments. Most previous research, though assessing some parts of the built environment according to 5D planning elements in the context of TOD, has only explored cities in Western countries as settings for case studies [57]. Reviewing comprehensive, extensive literature on spatial road safety approaches, one study [57] recommends further exploration of all physical environments as a direction for future research. In order to expand our understanding of the role of compact development measures in traffic accidents and pedestrian safety, the Asian city of Seoul, Korea, is a crucial study subject with a high-density, less dependence on automobiles, and welldeveloped public transit systems. In particular, the current study focuses on pedestrian crashes associated with Seoul's urban physical environment. The reason for this is, though pedestrians are a vulnerable user group on roads, they are a major measure to promote walking activity for desirable development, as well as sustainable transport systems [58].

Study Area
Seoul is a megacity characterized by a high population density, mixed land-use, and public transit-oriented transportation systems [59]. Among comparable cities in other Organization for Economic Cooperation and Development (OECD) countries, Seoul reports a relatively high number of fatalities by traffic accidents [60,61], with 100 fatalities per million people in 2017. That figure is twice the average for OECD countries (56 fatalities per million people).
This study analyzes 31,999 cases of pedestrian-vehicle crashes out of a total of 120,329 traffic crashes in the Seoul metropolitan city over three years, spanning 2015 through 2017. For spatial analysis and regression models, this study aggregates crash data based on a 500-m grid cell unit. Our statistical models-specifically, negative binomial regressions-were designed to examine relationships between features of the urban physical environment and pedestrian crashes in Seoul.

Unit of Spatial Analysis
This study analyzes pedestrian-vehicle crashes based on a 500-m grid cell unit to test relationships between 5D measures of urban physical environments (the planning elements of TOD [21,62]) and pedestrian crashes. Previous empirical studies have adopted diverse spatial units with administrative boundaries, including states [63], metropolitan areas [64], and counties [13]. Other research has employed parameters according to census geographical boundaries, such as counties [13], census tracks [11,41,65,66], census blocks [36], traffic analysis zones (TAZs) [67], and voting districts (wards) [68], as well as road segments and intersections [57].
This study designates a 500-m grid cell as the spatial unit of analysis to determine homogeneous spatial characteristics of pedestrian-vehicle crash spots. Some studies have employed fixed distance grid cell units (instead of zonal or regional ones) for examination of road safety, such as 0.1 square miles [69], 1 square mile [70], or multiple units from 1 to 100 square miles [71]. For example, one study [72] identifies the range from 0.25 to 1.0 miles as an acceptable walking distance. Another study [11] describes an association between pedestrian safety and neighborhood characteristics by setting 400-m spatial units as walkable boundaries of neighborhoods. Notably, one study uses a 500-m grid cell as a spatial unit to analyze pedestrian-vehicle crashes in greater King County, Washington, USA [55]. That research analyzes the frequency of traffic accidents by 305-, 500-, and 1000-m units, respectively, finding that frequency by 500-m units was homogeneously distributed, and less dispersed across units in comparison to the other two spatial units. Another case study [73] in the city of Seoul uses a 500-m grid cell to analyze spatiotemporal patterns in pedestrian crashes. Accordingly, this study divides Seoul into 500-m grid cells. Furthermore, it is not uncommon in Korea to prescribe transit station areas with 500-m boundaries insofar as that distance is considered accessible through walking.
Pedestrian-vehicle crash spots in Seoul are illustrated by grid cells in Figure 1. After eliminating from analysis all the cells without buildings and inhabitants, we aggregated the values of the dependent and explanatory variables (Table 1) for a total of 2267 cells to analyze the relationship between 5D measures and pedestrian crashes. miles as an acceptable walking distance. Another study [11] describes an association between pedestrian safety and neighborhood characteristics by setting 400-m spatial units as walkable boundaries of neighborhoods. Notably, one study uses a 500-m grid cell as a spatial unit to analyze pedestrian-vehicle crashes in greater King County, Washington, USA [55]. That research analyzes the frequency of traffic accidents by 305-, 500-, and 1000m units, respectively, finding that frequency by 500-m units was homogeneously distributed, and less dispersed across units in comparison to the other two spatial units. Another case study [73] in the city of Seoul uses a 500-m grid cell to analyze spatiotemporal patterns in pedestrian crashes. Accordingly, this study divides Seoul into 500-m grid cells. Furthermore, it is not uncommon in Korea to prescribe transit station areas with 500-m boundaries insofar as that distance is considered accessible through walking.
Pedestrian-vehicle crash spots in Seoul are illustrated by grid cells in Figure 1. After eliminating from analysis all the cells without buildings and inhabitants, we aggregated the values of the dependent and explanatory variables (Table 1) for a total of 2267 cells to analyze the relationship between 5D measures and pedestrian crashes.    Table 1 shows summary statistics of the dependent and independent variables used in our analysis, along with their descriptions and data sources. The dependent indicator is a counting variable-the frequency of pedestrian-vehicle crashes for the three years between 2015 and 2017 by 500-m grid cell. Crashes are counted by the seriousness of pedestrian injury-that is, fatality (death), major injury, or minor injury inflicted on pedestrians by vehicles. The number of crashes causing pedestrian death was much lower than the other two types of injuries (0.26 death per grid cell vs. 5.89 for major injuries vs. 8.22 for minor injuries per grid cell). For independent variables, we employed 5D urban environment measures for TOD, as well as topography slope and exposure variables, including total population density, total length of road networks, and total area of green space (see Table 1).

Variables and Models
Here, each 5D category has its representative indicators as independent variables. First, density is represented by four specific floor area variables-namely, single-family housing (SF_den), multi-family housing (MF_den), commercial use, and office use. Second, diversity is composed of the land-use mix index (LUM), the residential/non-residential land-use mix index (RNR), and the standard deviations of total floor areas.
Third, the design category has three variables mainly associated with roadway design features-namely, the number of three-way intersections, the number of four-way intersections, and the number of U-turns. Fourth, this study considers four variables for distance to transit, including the average distance from the pedestrian crash point to the closest bus stop, the average distance from the pedestrian crash point to the closest subway station, the number of bus stops, and the number of subway stations. Fifth, this study considers six variable destination categories, including the number of elementary, middle, and high schools; the number of colleges; the number of retail stores; the total floor area of hospitals; the total floor area of religious buildings; and the number of traditional markets. Finally, this study considers three additional variables (i.e., population density, road length, and green area) to control for the effects of exposure variables on pedestrian crashes, together with one additional variable for the spatial autocorrelation correction (SAC) factor to control for spatial autocorrelation [74].
This study considers population density and total road length variables as proxy variables for ambient population and traffic volume, respectively. Most green space is characterized by mountains and rivers that are not developable in Seoul. Though the green space variable may typically be considered a "design" factor, this study considers design factors to be geometric components directly related to roadway design. Thus, the green space area in a 500-m grid cell indicates land-use characteristics herein. Traffic accidents are rarely occurring events [55]. Therefore, distributions of the three types of pedestrian-vehicle crashes counted within the 500-m grid cells are positively skewed (Figure 2). intersections, and the number of U-turns. Fourth, this study considers four variables for distance to transit, including the average distance from the pedestrian crash point to the closest bus stop, the average distance from the pedestrian crash point to the closest subway station, the number of bus stops, and the number of subway stations. Fifth, this study considers six variable destination categories, including the number of elementary, middle, and high schools; the number of colleges; the number of retail stores; the total floor area of hospitals; the total floor area of religious buildings; and the number of traditional markets. Finally, this study considers three additional variables (i.e., population density, road length, and green area) to control for the effects of exposure variables on pedestrian crashes, together with one additional variable for the spatial autocorrelation correction (SAC) factor to control for spatial autocorrelation [74]. This study considers population density and total road length variables as proxy variables for ambient population and traffic volume, respectively. Most green space is characterized by mountains and rivers that are not developable in Seoul. Though the green space variable may typically be considered a "design" factor, this study considers design factors to be geometric components directly related to roadway design. Thus, the green space area in a 500-m grid cell indicates land-use characteristics herein. Traffic accidents are rarely occurring events [55]. Therefore, distributions of the three types of pedestrianvehicle crashes counted within the 500-m grid cells are positively skewed (Figure 2).   This study uses a total of 2267 grid cells for analysis, excluding mountains and rivers. There are 476 (21.0%) grid cells with no pedestrian crashes, 1818 (80.2%) grid cells with no pedestrian crashes causing death, 633 (27.9%) grid cells with no pedestrian crashes causing major injury, and 618 (27.3%) grid cells with no pedestrian crashes causing minor injury. As shown in Table 1, the mean values are lower than the standard deviations for all types of injuries, which indicates an overdispersion. This overdispersion violates the homogeneity assumption for a general Poisson model. A negative binomial regression model (i.e., an extended model of the Poisson distribution) has been suggested to account for count scales, overdispersion, and unobserved heterogeneity in the data [75]. Table 2 shows the results of negative binomial models for the four types of pedestrian crashes (i.e., all, death, major injury, and minor injury). We applied negative binomial models based on the characteristics of dependent variables, following some previous studies [11,55,68,72]. We tested the variance of error (α) and variance to mean ratio (VMR). Analysis confirmed that the negative binomial regression model was more appropriate than the Poisson model. We also tested a zero-inflated negative binomial model in model 2, which has many grid cells of no pedestrian crashes causing death. Because the zero-inflated negative binomial model had not been converged, we applied a negative binomial model for model 2. In addition, we confirmed no multicollinearity issues among independent variables. Lastly, we confirmed that the goodness of fit of each model is reasonable, based on pseudo R 2 , the Akaike information criterion (AIC), and the Bayesian information criterion (BIC). * p < 0.10; ** p < 0.05; *** p < 0.01.

Density
As shown in Table 2, four density variables were used, including single-family housing, multi-family housing, commercial use, and office use. Though the density of single-family housing shows significant negative associations with all three types of pedestrian crashes, the density of multi-family housing is not statistically significant, except in model 2 (death).
On the other hand, the densities of commercial and office buildings show relatively higher positive associations with all types of pedestrian-vehicle crashes. It also should be noted that the coefficient and level of statistical significance in model 2 (death) are lower than in model 3 (major injury) and model 4 (minor injury).
Overall, the analysis results indicate that the densities of commercial and office buildings are positively related to pedestrian-vehicle crashes. This result is in line with the results of previous studies [9,14,44]. However, the analysis results in Table 2 show mixed findings on the relationship between density and pedestrian crashes, depending on the dominant land-use. Though one study [15] claims that high-density development tends to reduce traffic on roadways, and decreases pedestrian-vehicle crashes with lower rates of fatal pedestrian crashes, our study confirms that the relationships between high-density development and pedestrian crashes are different according to land-use types in terms of total floor areas of residential, commercial, and office buildings.

Diversity
As shown in the models in Table 2, three variables were employed for diversity measures, including the entropy index of land-use mix (LUM), the land-use mix of residential and non-residential buildings, and the standard deviations of their total floor areas. Analysis results show that the land-use diversity indices are positively associated with pedestrian crashes. This result is consistent with findings from a previous study [76], claiming potential conflicts between pedestrian and vehicle movements. In addition, the standard deviations of total floor areas of buildings show a statistically significant, positive relationship with pedestrian-vehicle crashes, except in model 2 (death). In Seoul, the heights and volumes of buildings vary greatly, with high-story buildings located in close proximity on the main roadways, and low-story residential, commercial, and mixed-use buildings clustered on back streets. These areas are usually characterized by greater and more active interaction between pedestrians and vehicles, which might cause a higher rate of pedestrian-vehicle crashes.

Design
As shown in Table 2, three variables were adopted as design factors, including the number of three-way intersections, the number of four-way intersections, and the number of U-turn-permitted nodes in the models. A high intersection density (meaning a greater number of intersection nodes per unit area) indicates small block sizes, which tend to promote walking-friendly built environments, and thus, an increase in the number of pedestrians.
On the other hand, a high node density may lead to frequent vehicle stops, suggesting that pedestrian activities occur in a more complicated environment due to many intersections. Therefore, a narrow block design can be both beneficial and detrimental for pedestrians' safety. Analysis results indicate that the number of points of intersection is most likely to be positively associated with higher pedestrian crashes, with the exception of four-way intersections in model 2 (death). The main reason for this is because the risk is amplified by the higher number of intersection points [77], thus yielding a greater chance for pedestrians to encounter a vehicle.
Both U-turn-allowed intersections and elevated/underground passageways may also increase the chances of crashes causing major or minor injury to pedestrians. However, the number of U-turns is only positively associated with fatal pedestrian crashes in model 2. This result implies that proper design measures for U-turns are critical to prevent fatal pedestrian crashes.

Distance to Transit
Four variables were used to capture the distance to public transit in the context of the 500-m grid cell: the average distance from the pedestrian crash point to the closest bus stop, the average distance from the pedestrian crash point to the closest subway station, the number of bus stops, and the number of subway stations within each 500-m grid cell.
Overall, proximity to public transit systems was shown to be more likely to increase the number of pedestrian crashes. In particular, pedestrian crashes causing major or minor injuries show statistically significant and positive associations with nearby public transit systems, and negative associations with distant public transit. In addition, fatal pedestrian crashes are more likely to be associated with nearby bus stations and the presence of many subway stations. Although the existence of bus stops and subway stations obviously facilitates the usage of public transit, previous studies have suggested that more pedestrianvehicle crashes happen in areas where transit stations are nearby and/or accessible to pedestrians [78], due mainly to there being more pedestrians in these areas [52,55,72]. Our results confirm that nearby bus stops and subway stations are positively related to pedestrian-vehicle crashes.

Destination Accessibility
As shown in Table 2, six variables were adopted for destination accessibility because they are closely related to pedestrian-vehicle crashes: number of elementary, middle, and high schools; number of colleges; number of retail stores; total floor area of hospitals; total floor area of religious buildings; and number of traditional markets. The presence of nearby schools is negatively associated with fatal crashes in model 2, and is positively associated with minor injuries in model 4. This result is in line with the two competing hypotheses around the effects of nearby schools in terms of pedestrian crashes. The presence of schools might result in a higher likelihood of pedestrian-vehicle crashes due to more students walking around schools [79]. On the other hand, we may assume a lower likelihood of crashes if traffic speed limit regulations are effective in designated "school zones" with very low speeds [80]. Our finding indicates that even though the high volume of pedestrians around schools increases the risk of pedestrian-vehicle crashes, lower speed limits and various other pedestrian safety measures in school zones counteract the pedestrian volume effect on fatal pedestrian crashes, thereby reducing the number of crashes that cause pedestrian fatalities.
This study finds similar results in the effects of the presence of retail stores on pedestrian-vehicle crashes. The number of retail stores is positively associated with pedestrian crashes in model 1 (all) and model 4 (minor injury), but not in model 2 (death). This finding is probably related to the locational characteristics of downtown or commercial districts where retails stores are found. The likelihood of a fatal crash within a downtown area with many retail stores is lower due to decreased traffic speed [8,35]. Similarly, the total floor area of hospitals showed positive associations with pedestrian crashes in all of the models, except for model 2 (death). In addition, the number of traditional markets showed positive associations with pedestrian crashes in all of the models. These results are related to the fact that hospitals and traditional markets attract many pedestrians.

Topography and Exposure Variables
As shown in Table 2, our findings indicate that gentle or steep slope areas are less likely to have pedestrian crashes than flat slope areas. Though this relationship is significant in model 1 (all) and model 3 (major injury), it is not significant in model 2 (death). Next, population density, one of the primary exposure variables, is positively associated with all types of pedestrian crashes. Nevertheless, it should be noted that the coefficient and the level of significance in model 2 (death) are relatively lower than the coefficient and the level of significance in model 3 (major injury) or model 4 (minor injury). Although higher density introduces higher exposure to pedestrian crashes, it leads to fewer cases of pedestrian crashes causing deaths or major injuries. This result is similar to the findings of previous research [15] identifying a lower rate of fatal crashes in highly dense areas.
The total length of road networks is another exposure variable; longer road networks in the unit of analysis might be associated with a higher risk of pedestrian crashes. According to analysis, the total length of road networks shows statistically significant and positive associations with all three types of pedestrian crashes.
Finally, this study also considers green space areas as an exposure variable. Green space areas are related to land-use diversity. Analysis results indicate that green space areas are negatively associated with all types of pedestrian crashes. In other words, more green space in a grid cell is related to a lower rate of pedestrian-vehicle crashes therein, mostly because a high ratio of green space in a grid cell can reduce exposure to pedestrian crashes by generating less traffic volume. This result is consistent with the findings of previous research [81] that reports a lower rate of pedestrian-traffic crashes in areas with more open spaces.

Discussion
Many researchers and policymakers expect to see a lower risk for pedestrian-vehicle traffic accidents owing to compact and mixed-use urban environments and transit-oriented development, which are believed to have advantageous effects in lowering vehicle-dependent traffic inducement [7][8][9][10]. Previous studies [11][12][13], however, have reported that pedestrianvehicle crashes have increased due to the tendency of more people to walk on streets because of pedestrian-friendly and transit-friendly physical environments. Taking a different point of view, other studies [14,15] have argued that TOD physical environments are effective in lowering the severity of pedestrian-vehicle crashes because of reduced vehicle speeds within the physical environments.
Thus, the relationships between TOD environments and pedestrian-vehicle crashes seem to be complex and cannot be easily generalized. In addition, most previous studies explore only some parts of the 5Ds (density, diversity, design, distance to transit, and destination accessibility) of TOD environments, focusing mainly on Western cities. Therefore, this study aims to identify evidence of the complex relationships in pedestrian-vehicle crashes with 5D measures in Seoul, a big city with a high-density mixed-use physical environment, and transit-oriented transportation systems.
Our findings lead us to conclude that TOD urban physical environments have the potential to increase the risk of pedestrian crashes without careful counterpart measures. Furthermore, although a TOD environment has positive effects in suppressing the frequency of automobile traffic, higher pedestrian volume means that more pedestrians may encounter more automobile traffic. Nevertheless, the results of this study demonstrate that the TOD environment of Seoul has positive effects in reducing the severity of pedestrian-vehicle crashes. More specific key findings are as follows.
First, this study confirms that though higher density in residential areas is associated with fewer cases of pedestrian crashes, higher density in commercial or office districts increases all three types of pedestrian crashes. This finding aligns with the findings of a few previous studies [9,14,44]. However, it should be noted that though a higher density is associated with higher exposure to pedestrian crashes, a higher density might lead to fewer cases of severe and/or fatal pedestrian crashes [15]. Next, this study indicates that mixed land-use is also strongly associated with a higher risk of all three types of pedestrian crashes. Greater mixed land-use is more likely to increase pedestrian crash risk across different severity levels [49,76]. This result may be related to the characteristics of a big city in Asia that has adopted diverse land-uses over most of its areas, thereby mitigating the other benefits of compact development. Therefore, integrating traffic-calming strategies into compact development principles and practices can effectively control fatal pedestrianvehicle crashes, especially in high-density, mixed land-use areas of development.
Second, this study indicates that three-way and four-way intersections are highly associated with pedestrian crashes. In particular, a higher number of three-way intersections is more likely to increase all three types of pedestrian crashes, particularly fatal crashes. This finding is similar to the results of previous studies [72,73,78]. Most three-way intersections in the city of Seoul have non-signalized systems with lower direct visibility between automobiles and pedestrians. Higher numbers of pedestrian crashes and more severe pedestrian crashes near intersection areas should garner policy attention to promote pedestrian safety. This study also finds that the number of U-turns is highly associated with fatal pedestrian crashes. Therefore, mitigation measures should be implemented to reduce the likelihood of pedestrian crashes in places where cars frequently make U-turns.
Third, this study finds that distance to public transportation is highly associated with all three types of pedestrian crashes. In other words, pedestrian crashes are more likely to increase in spots with nearby transit stations, including bus and subway stops. This finding indicates that securing the traffic safety of pedestrians near public transit stations is an urgent matter. Although many Asian cities, such as Seoul, are hubs of public transportation with numerous bus stops and train stations, higher rates of fatal crashes around transit stations is a serious problem in need of solutions [73].
Finally, destinations are important factors in pedestrian crashes. For example, though the proximity of schools is positively associated with minor pedestrian crashes, it is negatively associated with fatal crashes. This finding indicates that mitigation measures near school zones have positive impacts on pedestrian safety in terms of fatal crashes. In contrast, retail stores, traditional markets, and hospitals are associated with many pedestrian crashes, resulting in major, as well as minor, injuries. This finding is consistent with the findings of previous research [82]. Therefore, pedestrian safety measures should be implemented to reduce the likelihood of pedestrian crashes near major destination facilities.

Conclusions
This study examines pedestrian safety issues in Seoul, South Korea, a TOD environment, with evaluations of 5D measures on pedestrian crashes. It is well known that the development of compact and mixed-use urban environments decreases car-oriented travel patterns, reduces traffic congestion, prevents air pollution, and supports healthier cities. However, this study confirms that compact and mixed-use urban development is more likely to be associated with pedestrian-vehicle crashes in concentration areas of commercial and office facilities. This finding indicates that pedestrian safety policies should be implemented to mitigate pedestrian-vehicle crashes in high-density and mixed-use urban environments. On the other hand, this study also finds that some adverse effects can be counterbalanced or offset by beneficial trade-offs generated through 5D measures. Accordingly, urban built environments promoting high-density and mixed-use development should be carefully monitored and planned to improve pedestrian safety, especially in the highly dense urban settings of Asian cities. Leveraging the approaches and findings of this study, future studies should attempt to answer fundamental policy questions, and garner real experience from diverse global urban contexts and settings regarding the risks, benefits, and trade-offs in pedestrian-vehicle crashes.
Author Contributions: H.S., Conceptualization, writing-original draft preparation, formal analysis; S.L., methodology, writing, validation, funding acquisition, supervision; S.C., methodology, writing, validation, funding acquisition; J.Y., methodology, data curation, writing, visualization. All authors have read and agreed to the published version of the manuscript.

Conflicts of Interest:
The authors declare no conflict of interest.


From Social Protection to Personal Protection: Implications for an Integrated Framework of Retirement Planning for Informal Workers in Ghana

Without a mandatory retirement age, many informal workers are exploring diverse ways of ensuring their well-being as they age. This exploratory study focuses on the retirement plans of workers in Ghana’s informal sector to inform interventions to ensure their well-being. Findings from 35 in-depth interviews among self-employed informal workers in Adum-Kumasi, the largest hub of Ghana’s informal work, highlight that retirement planning is centred on self-protection through investment in economic and non-economic activities. The study contributes to the discourse on extending social protection coverage to informal work settings. It further recommends an integrated policy framework for social protection to cover a broad range of domains that are important for the well-being of informal workers in later life.

Introduction
The advent of modernization and social change has necessitated most African states to consider the implementation of social protection measures to substitute traditional roles of supporting the family (Abdulai et al., 2019). Globally, all societies recognize the need to ensure that their citizens are protected against loss of income in the event of social risks (Mokomane, 2013). Particularly in Africa, social protection issues have gained critical attention in policy discourse (Govindjee, 2019). This is reflected in response to finding alternative measures for extended family support which has over the years been the basis for the sustenance of society, in times of need and crisis (Doh et al., 2014a). In fact, the most common type of social protection that pertains to the labour force is pensions. These are contributory pension schemes, managed by the state, which generally aim to facilitate the retirement planning of the workforce and to provide a substantial level of income security in old age (Arza, 2015).
Owing to this, retirement planning has emerged as a main global priority in social protection, and as one of the fulfilling phases of one's lifetime, not desultory except through planning and continual evaluation (Onduko et al., 2015). A vital policy concern in this region is how to get persons to plan for retirement (Guven, 2019). This is because existing literature on retirement in both developed and developing countries underscores two distinct views on how older informal workers adjust or cope in later life (Devereux & Getu, 2013;Mumtaz, 2022;Wang & Shi, 2014). While some retirees adjust constructively by maintaining good social networks, others prefer to engage in other socio-economic activities (Dovie, 2017). Retirees who have difficulty adjusting in later life face financial hardship as well as social contempt (Musila et al., 2019). Social protection has consequently become a crucial component of social policy to address poverty and ensure the well-being of vulnerable workers in later life (Gerard et al., 2020). Yet in Africa, the coverage of pension systems is more structured for those working in the public sector, where age is the main determining factor for retirement (Getu & Devereux, 2013;Miti et al., 2021). Though considerable disparities within the region persist, only 11.6% of older persons contribute to pension schemes, implying a substantial gap in coverage among this cohort (Guven, 2019). This is more complicated in regions such as Ghana where significantly informal workers dominate the economy (Lund, 2012).
In Ghana, there is a surging interest to extend social protection coverage to people working in the informal economy (Adzawla et al., 2015). This interest has risen through the realization that the right to social protection is not yet a reality for the 80% majority in the informal sector of Ghana's working population (Collins-Sowah et al., 2013). As a result of this, the Social Security and National Insurance Trust Fund (SSNIT) introduced the Informal Sector Social Security Scheme in 2005 (Kubuga et al., 2021). However, the participation of workers in this sector was very minimal (Osei-Boateng & Ampratwum, 2011). To address this policy gap, in 2009, a third-tier pension system, merging mandatory with voluntary retirement plans, was introduced by The National Pensions Act, Act 766 to address declining investment returns and especially improve access to informal sectors (Nunoo, 2013;SSNIT, 2015). The third-tier pension scheme has been in place for over a decade; unfortunately, its goal to offer a comprehensive and organized retirement plan has remained challenging. This is acknowledged by the incessant low patronage and awareness of the new pension system among informal sector workers (Anku-Tsede, 2019; Anku-Tsede et al., 2015;Boyetey et al., 2021).
Given that informal workers at present are not shielded by any retirement plan, are there opportunities for exploring other forms of social protection to ensure their well-being in their later life? This study with the aid of an exploratory design discusses the retirement plans of informal sector workers in Ghana and offers a re-think of the social protection measures to safeguard informal workers who are at risk of poverty in their old age.

Theoretical Framework
A plethora of theoretical arguments, for instance, disengagement theory, the life course perspective, and role theory, has been proposed as models for offering a comprehensive perspective on retirement decision making, retirement transition, and retirement satisfaction of employees (Lytle et al., 2015;Wang et al., 2008). Although the retirement process has been widely studied, theoretical postulations on the retirement process of informal workers who have no mandatory or statutory retirement procedures, are yet to receive attention. However, considering the unique characteristics of informal workers and their understanding of retirement (Oteng et al., 2021), it is apparent that the continuity theory could offer a new perspective on the retirement decisions of informal workers. According to the theory of continuity (Atchley, 1989), retirement is not considered as a stressful event of disengagement from active work life; however, it is an opportunity for older adults to maintain their work life, a lifestyle which offers higher levels of psychological well-being (Von Bonsdorff et al., 2009). Individuals who are strongly engaged in their employment, according to the theory, are more prone to seek continuity through several forms of participation in work life (Atchley, 1989). Specifically, retiring in the informal economy is conceived as a partial withdrawal from work, not an event, indicative that working in the informal sector allows a level of flexibility into retirement transition juxtaposed to jobs in formal organizations.
In contrast to the abrupt transition of formal jobs associated with disengagement theory, the retirement transition and decisions of informal workers corroborate the basic tenets of continuity theory in that individuals who enjoy their work, continue to work until their health declines, and therefore tend to plan for retirement by engaging in other business ventures that are flexible and less straining to their health. The reason for staying away from work momentarily is strongly contingent on having a financial haven and not necessarily a state pension policy in old age. Therefore, the desire to continue working is a result of fear of the financial insecurity retirement would bring to their remaining years. Moreover, complete retirement for informal workers is a function of poor health; however, mandatory retirement is perceived more as a health benefit during old age (Oteng et al., 2021). Atchley's continuity theory recognizes the disadvantages of a retirement plan that considers a complete cessation from work without having other work aspirations. Therefore, this model addresses retirement as a stage of life and recognizes that retirement planning is connected to balancing work and well-being in later life. The theory of continuity offers a nuanced perspective of how the retirement plans of older workers influence their well-being. Although this theory does not consider minority status issues or vulnerable groups within the working population (for example informal workers) and considers older workers as homogenous, it has the flexibility to do so. The study, therefore, applies the continuity theory as a useful perspective in understanding the retirement plans of informal workers in Ghana.

Study Design
The study aimed at gathering an in-depth perspective of informal sector workers in Ghana on their retirement planning and, therefore, adopted an exploratory design. This is to glean new topics that have received little or no prior investigation (Creswell, 2013).

Study Setting and Population
The research setting was the Central Business District (CBD) of Kumasi, the biggest informal economic hub in Ghana. In addition, family ownership of informal businesses predominates the CBD, because the family provides an economical source of the workforce (Chen, 2020). Moreover, the lack of trust on the part of individuals in the informal sector discourages the establishment of joint ventures and partnerships (Osei-Boateng & Ampratwum, 2011). The study population, therefore, consisted of all informal workers engaged in family enterprises. This study, therefore, conceptualizes family-owned enterprises to comprise any enterprise or firm owned and managed by Ghanaian individuals in which two or more family members are involved.

Selection of Participants
Participants who could provide in-depth information by their status and experience as informal sector workers were selected for inclusion with the aid of an expert purposive sampling technique. Expert sampling is a type of purposive sampling technique that is employed to study individuals with a high degree of knowledge about a subject and the study area. This is required in qualitative research, when a study needs the opinions or assessment of people with specific expertise, highlighting potential new areas of interest or opening doors to other participants (Etikan et al., 2016). Accordingly, in this study, individuals aged 50 years and above and working in the informal sector were eligible to partake in the study. The study also included only participants who were owners of family enterprises at the time of the study. Previous studies have shown that people should start planning for retirement at least ten years before their expected retirement date (Manoli & Weber, 2016;Sundström et al., 2020). Therefore, family business owners who were less than 50 years at the time of the study were in the exclusion criteria.

Data Collection Process
Data were collected from 35 participants through in-depth interviews with the aid of a semi-structured interview guide. The data analysis was done concurrently with the data collection; hence, saturation was reached after the 35th interview. Following previous studies (Vandecasteele et al., 2015;Saunders et al., 2018), three more interviews were conducted to confirm that there were no new emerging themes. The interview guide had questions that explored participants' perceptions and accounts of their retirement planning. With the eligibility criteria as a guide, one of the researchers made initial contact with participants to arrange for the interview dates. All interviews were scheduled before the actual interview time and generally conducted in the place of work of participants and their preferred time of 1 pm to 4 pm. From November 2017 to January 2018, face-to-face in-depth interviews were conducted with each participant to collect the data. The interviews were audio-recorded with the permission of participants and later transcribed verbatim.

Data Analysis
All the audio interviews were analysed with the aid of Attride-Stirling's (2001) thematic network analysis. Thematic network analysis reveals the embedded meanings in the text at different stages where a systematic method is followed. The study consequently employed a step-by-step process in the analysis of the data. Open code, an aspect of NVivo software that facilitates the coding of raw data, was used. The entire set of data went through four stages of analysis. These included coding, generating basic themes from the codes, categorizing the basic themes into organizing themes, and deducing an overall theme from each, respectively.

Ethical Considerations
Before data collection, the study obtained ethical approval from the Ethics Committee in KNUST. The purpose of the research was elucidated to participants who were allowed to decide their participation in the study. Subsequently, participation was entirely voluntary and not mandatory. To maintain anonymity and confidentiality, the indicators identifying specific respondents were avoided in the study. As a result, names mentioned in reporting the findings were pseudonyms to help protect the identity of the participants. In all, participants' rights to privacy and protection from personal harm were carefully observed.

Results
The socio-demographic characteristics of participants and the thematic findings of the study are presented in this section.

Socio-Demographic and Business Characteristics
Concerning socio-demographic characteristics, most participants were males and between the ages of 50 and 54 years. In terms of educational attainment, most participants had the secondary school level of education. In addition to participants' characteristics, questions related to the type of work, work experience, and how the business started were asked. Participants had varied informal economic activities but were dominated by the sale of clothing and fashion items. Most participants in the study started their business with their own capital and had at least 10 years of business experience at the time of the study. Table 1 displays some of the personal and business characteristics of the research participants.

Thematic Findings
At the time of the study, all participants had not been registered with the state's pension plan. Participants were therefore asked to share their specific retirement strategies. Emerging themes from the interview data revealed five retirement strategies (see Fig. 1): housing plans, senior entrepreneurship, spiritual investment, portfolio investment, and investing in children.

Housing Plans
The first form of retirement strategy was housing plans. From the interviews, participants stressed the importance of housing arrangements by indicating that it was very uncomfortable renting when you could afford a small apartment on your own. One participant summed up the shared opinion by stating:

Senior Entrepreneurship
For most participants, once retirement is not mandatory, they would want to be economically active by investing in businesses that required less physical effort.
"I would want to make a monthly contribution so that if I can no longer work, I could stay in the house and engage myself in other ventures like farming especially raising farm animals like rabbits which do not require using a lot of energy." (Baah,51 years).
It is also worth mentioning that research participants highlighted the importance of having adequate financial resources in the execution of this strategy.

Spiritual Investment
Others preferred to engage in spiritual activities than economic ones. This response reflects the shared view;  (Eben,52 years) Participants asserted that focusing on the work of God, allows them to have adequate time for their spiritual life, which has been overlooked over the years because of their involvement in economic activities. Participants explained that it was also a time to ensure the spiritual well-being of their families.

Investing in Children
Another key finding that emerged from the interview data was the reference to investing in children as a strategy to ensure social protection. One of the research participants argued: "Because we don't benefit from any insurance package but when your children take over, they will take care of you. Investing in my children by giving them proper education and grooming them to take over the business is my greatest plan" (Kwabena,56 years) Grooming children as successors of the business was therefore one of the retirement strategies of family business owners in this study.

Portfolio Investment
In the study, participants mentioned portfolio investment as one of their retirement plans. The specific portfolio investment encompassed investment savings in banks, stocks, and insurance companies.
"If one intends to retire, I think you should have a portfolio, something aside from your business that earns you money. For me, I have some investments in the Ghana Stock exchange, at the Data bank; Mutual fund and some in treasury bills. I started this quite early. I would not have any problems in case of contingencies" (Ivy,53 years) However, participants argued that investing in these banks and insurance companies was sometimes risky because they were not trustworthy. Sharing their experience, one of the participants explained that: "Yes, I have started preparations but I have stopped because the financial institutions cannot be trusted. I started saving with some mobile bankers, not knowing they were not legally permitted to operate." (Ama, 51 years).
For others, the decision to change or have additional plans was contingent on the financial resources available. This highlights the importance of a high level of income in the execution of retirement strategies. Although there are some non-financial plans, the indispensable role of financial resources in ensuring the feasibility of these plans cannot be underestimated.

Discussion
Findings from this study revealed five retirement plans of informal workers encompassing portfolio investment, housing plans, spiritual investment, investing in children, and senior entrepreneurship. The study concludes that the retirement plans for most informal workers are flagged on personal insurance and self-protection rather than on social protection. Studies have characterized retirement planning according to three domains: self-insurance, self-protection, and public protection (Denton et al., 2004;Muratore & Earl, 2010). First, self-insurance includes personal financial plans made by individuals to improve wealth in later life (savings accounts, investments, and private insurance policies for assets and health care). Second, self-protection includes personal non-financial preparations made by individuals to maintain health and well-being in later life (these may include healthy lifestyle choices, engagement in social support networks [including family], and seeking a safe physical environment). Third, public protection includes benefits provided by the Government to promote health, wealth, and well-being in later life; these may include pensions, public health programs, health services, or housing programs. It is very apparent from the above typologies that there is a paradigm shift of social protection where governments provide social security for all workers to a model of personal protection where workers initiate and plan for their wellbeing in later life. This is challenging especially for informal workers who do not have enough financial resources but would have to continue working despite poorer health and working conditions until they have enough to secure these plans. Also, significantly, the economic challenges triggered by the Covid-19 pandemic have had serious implications for older informal workers' economic participation and security in later life. Relying on self-issuance schemes in this post-pandemic era may not be adequate considering the meagre financial resources of informal sector workers in Ghana. Extending social protection schemes sustainable and relevant to social needs in conjunction with the personal protection plans may liquidate poverty and the vulnerability of the informal sector workforce in Ghana.
The study further supports the continuity theory by demonstrating that older adults engaged in informal work maintained a continual level of participation in enjoyable activities in the attempt of ensuring increased levels of work engagement. The retirement plans of informal workers in the study corroborate the basic tenets of continuity theory as it is geared towards enhancing psychological well-being through finding meaning in later life activities.
Retirement planning in this study did not only encompass financial plans; savings, insurance, and investment but also non-financial plans such as spiritual investment. Informal workers were interested in their spiritual well-being after they transitioned from work. At the personal and organizational level, spirituality plays a significant role in the retirement planning process (Earl, 2010). It is clear from the study the interplay between spirituality and work in the retirement planning process, as well as the value of spirituality in the personal lives of informal workers as they transit into retirement. Spirituality, according to Dik and Duffy (2009), serves as a caveat for an avocation after retirement. Many family business owners in this study who were notably Christians were prepared to explore religious work as a form of economic activity after their retirement. Akin to spiritual investment, children were conceived as part of the retirement plans in terms of business succession. Substantial studies have established that children are a source of traditional social support for older persons (Dovie, 2018;Kpessa-Whyte & Tsekpo, 2020). Premising on the findings of the study, informal workers consider children as success legacy and source of wealth in later life. Notably, family business owners in the informal sector would endeavour to ensure the survivability of the business up till the next generation and precisely build up the social capital of the business (Gedajlovic & Carney, 2010). Family business owners would always encourage the transition of the business to the next generation. For most of them, since they had been socialized into their current kind of business, they were also more willing to socialize their children into the business. This encompassed knowledge concerning retirement planning through mentorship, sharing of important tacit knowledge, and having positive role models from co-workers within the business. Parallel to this, informal workers who are not likely to plan for their retirement would do so for cultural reasons. The reality is that people are not likely to spend time planning about retirement because thinking about retirement could mean closely thinking about one's death (Houlding, 2018;Valentish, 2021). This is a critical source of concern in the retirement process considering that the planning for retirement and the expectations of death are important stages individuals must go through in their lives. Retirement planning consequentially can be viewed as a cultural norm passed on from one generation to the other through the process of socialization. Therefore, succession, socialization, and religion were socio-cultural elements embedded in the retirement planning process of informal workers in this study. Although these factors are invaluable in the retirement planning of informal workers, these are under-studied in the extant literature, particularly in developing countries (Lytle et al., 2015). Nonetheless, this present study highlights that culture, family, and succession constitute a broader influence in the retirement planning of workers. These factors with little reliance on any social protection measure formed the bedrock of the personal protection plans of informal workers in Ghana.

Implications for Policy and Practice
The discourse on social protection makes a case for an extension of coverage to enable informal workers to access the contributory pension scheme during their working lives. Policy responses particularly in Ghana in the past decade have extended coverage through the third tier of the state's pension scheme to provide income support and access to health care for informal workers and other vulnerable groups. However, informal workers presently face the risk of economic insecurity on their own. This study has revealed that social protection for informal workers such as pension schemes is not exhaustive to ensure the well-being of older workers and workers approaching old ages in the informal sector. To supplement the existing policy programmes, investment strategies, specifically housing, portfolio, children, and spirituality are expedient for the active and productive ageing of informal workers.

Conclusion
To promote decent work and enhance the health and wellbeing of informal workers as encapsulated in the third and eighth goals of the UN Sustainable Development Goals, the state must provide a comprehensive and integrated model of social protection. This should encompass diverse domains and be custom-tailored to the needs of informal workers in Ghana. Further, efforts should be taken by the state and civil society to ensure quality education and health care to induce the informal sector workers' enrolment in this new all-inclusive social protection scheme.


Agriculture Cyber Physical System for Crop Recommendation

: Agriculture plays a significant role in the Indian economy. Agriculture employs more than 60% of India's population, and agriculture generates one-third of the country's revenue. As a result, it plays a vital part in the country's development. A variety of agricultural difficulties continue to hamper the country's progress. Choosing modern agriculture that integrates modern styles could be one solution to these issues. As a result, Agriculture Cyber Physical Systems, which combine IoT with other technologies such as Artificial Intelligence and Machine Learning, can make agriculture smarter. The Agriculture Cyber Physical System can help in increasing crop yields, reducing water waste, and reducing fertilizers overuse, among other things. This study is different in that it measures variety of aspects of the agricultural field that have a direct impact on crop choices. Second, it sends this information to a server, which then uses it to forecast farm-ready yields.

INTRODUCTION
In this advanced world, the majority of farmer have absence of legitimate information in regards to cultivating and horticulture making it difficult. Most piece of cultivating and farming related exercises depend on expectation and anticipation. At the point when it fails, farmer needs to bear huge losses. With depleting resources, reducing land sizes and increase in input and labour costs, combined with the uncertainty of various factors like weather, market prices etc., agriculture in India has become a profession which is full of risks. The advancements in technology must be worked upon across various disciplines and it's already shown dramatic improvements in many fields. Agriculture, on the other hand, has not got the benefit of such innovations. Our intention from this project is to at least one part of agriculture processes, that is selection of best crop for the farm. Traditionally farmers select the crop based on various factors such as market demand, and for the convenience farmers select the crop which gives most profit and requires less investment, this results to a problem of monoculture. Monoculture is that the agricultural practice of growing one plant species across a huge acreage. Instead of growing a spread of crops, as farmers have done throughout most of human history, they instead tend to land that produces only one type of crop.

A. Agriculture Cyber Physical System
In its most basic form, a Cyber Physical System (CPS) is a platform that consists of a mechanical system controlled by computer algorithms and is strongly connected with the Internet and its networked users. The platform's physical-mechanical components, which are represented by smart sensors and actuators, and software components, which are represented by computer and networking devices, are inextricably linked. Agriculture cyber-physical systems (ACPSs), or CPSs built and used in agriculture, may collect fundamental and timely information with high granularity on the climate, soil, and crops, allowing for more accurate agricultural management systems.

C. Artificial Intelligence
Artificial Intelligence or AI which stands for intelligence refers to systems or machines that mimic human intelligence to perform tasks and can iteratively improve themselves based on the information they collect. AI manifests in a number of forms. Artificial intelligence technology is supporting different sectors to boost productivity and efficiency. AI solutions are assisting to overcome the traditional challenges in every field. Likewise. AI in agriculture is helping farmers to improve their efficiency and reduce environmental hostile impacts. The agriculture industry strongly and openly embraced AI into their practice to change the overall outcome. AI is shifting the way our food is produced where the agricultural sector's emissions have decreased by 20%. Adapting AI technology is helping to control and manage any uninvited natural condition Machine learning is the branch of computer science which is used to construct algorithms which exhibit self-learning property i.e., learning which is done by the machine itself hence the term "Machine Learning". It is considered to be one of the major areas under Artificial Intelligence. For a machine to become intelligent like a human mind, it has to first think and learn like a human. Human mind learns from past data and experiences that it is exposed to and based on that it takes decisions in future.

E. Problem Statement
Monoculture farming has become more common over the last few decades, and while it often helps improve a farmer's yields initially, it is causing great harm to the local environment, as well as the world as a whole. To eliminate the problems associated with monoculture like hinger use of pesticides, excessive use of fertilizers, soil degradation, loss of fertility, Overuse of Water. etc., we are going to develop a solution using the technologies like IOT, Artificial Intelligence and Machine Learning etc.  3) Collection of all the hardware and software components required for the project. 4) Designing and Assembling the Sensors and other hardware components for making complete IOT System. 5) Building the Machine Learning Model using training dataset, and checking the accuracy of model using testing data. 6) Integrating IOT system and ML Model inside one graphical user interface by which we can monitor the collected data form farm and use this data to predict the best suitable crop. 7) Testing the whole system, and correction if any.
II. LITERATURE REVIEW 1) "Enhancing precision agriculture by internet of thing and cyber physical systems. Authors: Roberto Fresco, Gianluigi Ferrari, Published in 2018" This paper explores all the cutting-edge challenges and solutions required to implement the digital agriculture framework, intended as the evolution from Precision Farming to connected, knowledge-based farm production systems, in a context where digital technologies are first-class elements for the automation of sustainable processes in agriculture.

2) S. Siva Chandran, K. Balakrishnan, and K. Navin's "Real Time Embedded Based Soil Analyzer"
In this paper, Real time embedded based soil analyzer is used to do analysis of various soil nutrients parameters with the help of the pH value and the, soils Electrical Conductivity (EC). Depends on the pH value, The availability of various nutrients is calculated, adding today's technology towards agricultural fields, a cost-effective Real Time Embedded Based Soil Analyzer is to be designed with a rapid and dependable automated system that uses the pH value to analyses various soil nutrients.

3) "Farmer's Handbook on Basic Agriculture, A holistic perspective of scientific agriculture by Dr. P. Chandra Shekara, Dr. N.
Balasubramani, Dr. Ajit Kumar, Bakul C. Chaudhary, Dr. Rajeev Sharma" An Organization of Ministry of Agriculture, Government of India brought this paper Farmer's Handbook on Basic Agriculture out to impart technical knowledge on Basic Agriculture to farmers to provide holistic perspective of scientific Agriculture. The first chapter, "General circumstances for crop cultivation," discusses the basic needs of farmers and the farming industry by offering basic information of Good Agricultural Practices (GAP) and raising farmers' awareness of essential elements in crop choices and cropping patterns.

4) Ciprian-Radu Rad, Olimpiu Hancu, Ioana-Alexandra Takacs, and Gheorghe Olteanu, "Smart Monitoring of Potato Crop: A
Cyber-Physical System Architecture Model in the Field of Precision Agriculture." In this paper authors have presented a precision agricultural management integrated system architecture for monitoring vegetation condition of potato crop based on Cyber Physical System architecture and design technologies. The proposed system allows farmers to follow the evolution of certain parameters of interest and take appropriate decisions in order to increase agricultural productivity. Finally, the concept presented in this paper have represented the start for others researchers like us in the field of precision agriculture

5) "Smart Farming Prediction Using Machine Learning by S.R. Rajeswari, Parth Khunteta, Subham Kumar, Amrit Raj Singh,
Vaibhav Pandey, Published on 7 May, 2019" In this paper, authors explored the machine learning concepts that can help in improving agriculture. This paper studies various machine learning algorithms which can be used for agriculture data 6) "Artificial Intelligence in Agriculture by, Arka Bagchi Associate Consultant, Mindtree" In this article, it is discussed that how AI can change the agriculture landscape, the application of drone-based image processing techniques, precision farming landscape, the future of agriculture and the challenges ahead. AI-powered solutions will not only allow farmers to do more with less, but they will also increase crop quality and speed up the time it takes for products to reach market. III.

REQUIREMENTS ANALYSIS A. Input Parameters
We are collecting the following data because there are numerous elements that influence the decision of choosing the best crop for the farm. 1) Temperature: The intensity of heat energy is measured by temperature. Most agricultural plants require a temperature range of 15 to 40oC for best growth. dispersion of crop plants and vegetation Temperature has a significant impact on crop germination, growth, and development. 2) Humidity: Water is present in the atmosphere in the form of water vapour, which is commonly referred to as humidity. The ratio of the amount of moisture present in the air to the saturation capacity of the air at a certain temperature is known as relative humidity.

3) Soil Moisture:
Water is a key component of a growing plant that it takes from the soil. Photosynthesis requires the presence of water. Plants can use the moisture range between field capacity and permanent wilting point. Clay soil will have more available moisture than sandy soil. Soil water aids in a variety of chemical and biological processes in the soil, including mineralization.

4) Soil Minerals and Organic Matter:
Soil mineral content is formed through the weathering of rocks and minerals as differentsized particles. These are the sources of plant nutrients, such as calcium, magnesium, sulphur, manganese, iron, potassium, phosphorus, and nitrogen. It provides crops with all major, minor, and micronutrients. It improves the soil's texture.

5) Soil pH Concentration:
The pH (hydrogen ion concentration) of the soil determines the soil reaction. Crop growth is influenced by soil pH, and neutral soils with a pH of 7.0 are optimum for most crops. Acidic soils are possible (7.0). Plants are harmed by low pH soils due to the high toxicity of Fe and Al. The availability of other plant nutrients is also hampered by low pH.

B. Soil Health Card
Soil health card is a printed report that shows the status of his soil in terms of 12 parameters, including Nitrogen (N), Phosphors (P), Potassium (K), Macro-nutrients like Sulphur (S), Secondary-nutrients like Zink (Zn), Iron (Fe), Copper (Cu), Manganese (Mn), Boron (Bo) (Micro-nutrients), Potential Hydrogen (pH), Electrical Conductivity (EC), Organic Carbon ( (Physical parameters). The Soil Health Card will next make fertiliser and soil amendment recommendations for the farm based on this information. N, P, K, and pH are among the characteristics necessary for the project, for which a Soil Health Card is required. Fig. 4 2) DHT11 Sensor: This sensor is a digital humidity and temperature sensor with a low cost. Despite the use of an ADC, this sensor produces digital output and may thus be directly attached to the data pins of a microcontroller. It also has an eight-bit microprocessor for serial data transmission of temperature and humidity information.

3) Soil Moisture Sensor:
The moisture sensor has three pins: one for voltage, one for ground, and one for analogue input. This sensor measures the moisture content of the soil (in volume percent). Because moisture content is measured in percentages, the analogue value must be mapped to a range of 0-100. The electrical resistance of the soil is the attribute exploited by this sensor. This sensor has two probes that allow the current to travel through the soil. It primarily consists of a text editor for writing code, a text console, a message area, and a toolbar with buttons for common functions. The programmes produced using this software are referred to as sketches. This software mostly uses C/C++ functions for coding. Fig. 11. Arduino IDE 2) Thingspeak Cloud Server: It's a free and open-source programme. This platform offers services for visualising, analysing, and aggregating live data flowing on a cloud server. It provides real-time visualisations of data submitted to this cloud server by various devices. It has the ability to run MATLAB code, so we can evaluate and process statistics as they occur in real time.
Prototyping is a common application for it.

A. Flow of Project
The project is divided into four major sections as shown figure: 1) Collection of data from IOT System through Sensors and Lab Tested data through Soil Health Card. The Figure 6 shows the experimental setup of IOT system for data collection. The setup contains Microcontroller that is Arduino Uno Rev 3, then sensors they are soil moisture, DHT11, and GPS module . In this Uno Rev 3 gives base for live streaming of temperature, humidity, soil moisture and sending the sensor information to the server using ESP8266 Wi-Fi to Think Speak Server.

D. Machine Learning Algorithms and Data Set
Dataset used for building predictive machine learning models is shown in table no 1, the dataset was built by augmenting datasets of rainfall, climate and fertilizer available for India, 1) Data Fields a) N -Nitrogen content in soil b) P -Phosphorous content in soil c) K -Potassium content in soil d) Temperature -temperature in degree Celsius e) Humidity -relative humidity in % f) pH -ph value of the soil g) Rainfall -rainfall in mm Classification is the process of a machine learning from a dataset or observations and then classifying fresh observations into one of several classes or groupings. The following machine learning models are used in the project, and they are discussed below. a) Decision Tree Classifier: The Decision Tree algorithm is one of the supervised learning algorithms family. The decision tree approach, unlike other supervised learning algorithms, can also be used to solve regression and classification issues. By learning simple decision rules inferred from past data, the purpose of employing a Decision Tree is to develop a training model that can be used to predict the class or value of the target variable (training data). c) Support Vector Classifier: The Support Vector Machine (SVM) is a common Supervised Learning tool for solving classification and regression problems. However, it is mostly utilised in Machine Learning for Classification difficulties. The SVM algorithm's purpose is to find the optimum line or decision boundary for categorising n-dimensional space into classes so that additional data points can be readily placed in the correct category in the future ©IJRASET: All Rights are Reserved | SJ Impact Factor 7.538 | ISRA Journal Impact Factor 7.894 | d) Random Forest Classifier: Random Forest is a well-known machine learning algorithm that uses the supervised learning method. In machine learning, it can be utilised for both classification and regression issues. " According to the name, "Random Forest" is a classifier that "contains a number of decision trees on various subsets of a given dataset and takes the average to improve the dataset's projected accuracy. Instead, then relying on a single decision tree, the random forest collects the forecasts from each tree and predicts the final output based on the majority votes of predictions.  After clicking on predict button we get the suggestion for the best crop to plant depending on the entered details V. FUTURE SCOPE A. The project has a very vast scope in future. This project can be implemented on a large scale in future. Project can be upgrade in near future as and when requirement for the same arises, as it is very adaptable in terms of expansion. As the population is growing rapidly and many new technologies are emerging during the years it is important that the, agricultural sector also should move forward in that direction. B. In this project is limited only up to prediction of crop on the basic of N, P, K, Humidity, Moister, pH, and Temperature. We can further add more attributes to this list to make prediction more accurate and Precise. C. Soil Health Card is being used for some input data, as it is cost effective. But further we can use N, P, K sensor and pH sensor for collecting same data from field. D. This project only focuses on crop prediction, further we can add more functionality to this project like fertilizer recommendation, Water Management, Pest Management, Crop Protection from Climate Change. Etc. E. This project can be more implemented and can be connect to the mobile application so that farmer can do the work when they are not present at home.
©IJRASET: All Rights are Reserved | SJ Impact Factor 7.538 | ISRA Journal Impact Factor 7.894 | VI. CONCLUSION As the food demand is increasing day by day due to increasing population, so the way of farming is very important to reach this demand of public. The traditional agriculture processes in India will not be able to feed such a large population. In order to do that our farmers have adopt new technologies. From this project we are taking one step towards making Indian agriculture more advance than it is today.