Assessment of spatial transferability of an activity-based model, TASHA
Spatial transferability has been recognized as a useful validation test for travel demand models. To date, however, transferability of activity-based models has not been frequently assessed. This paper assesses the spatial transferability of an activity-based model, TASHA (Travel Activity Scheduler for Household Agents), which has been developed for the Greater Toronto Area (GTA), Canada. TASHA has been transferred to the context of the Island of Montreal, Canada using the 2003 Origin–Destination (O–D) travel survey and the 2001 Canadian Census. It generates daily schedules of activities (individual and joint) for each individual in this region. The modelled activity attributes (frequency, start time, duration and distance) from TASHA and observed attributes from the 2003 O–D travel survey are compared for five different activities (i.e. work, school, shopping, other, and return to home). At the aggregate level, TASHA provides quite reasonable outcomes (in some cases – better results than for the Toronto Area) for all four attributes for work, school and return to home activities with few exceptions (for instance, school start time). The model outcomes are also promising for shopping frequency and start times; however, TASHA provides larger differences for average shopping durations and distances. Only the forecasts for all four attributes for the ‘other’ activity type differ greatly with the observed attributes for the Montreal Island. These large differences most likely indicate the differences in behaviour between the Montreal Island and the Toronto Area. In general, we conclude that re-estimation of model parameters and the use of local activity attribute distributions (frequency, start time and duration) is a desirable step in the transfer of the TASHA model from one context to another.
Urban Hierarchies and the Changing Characteristics of "Urban Professionals" in Toronto and Montreal: Between Convergence and Divergence
It has been amply demonstrated in the literature that the decade of the 1980s was a crucial one as regards what Ley (1996) terms the "shuffling of command and control" in the Canadian urban system. Toronto's position at the summit of the Canadian urban-economic hierarchy became more firmly entrenched than ever before, with the region increasing its lead over the country's other major advanced tertiary centres in terres of employment in the pivotal financial and business services sectors (Coffey 1994; Ley and Hutton 1991; Polese 1998). By 1991, some 25% of the Toronto Census Metropolitan Area's service sector jobs were in finance, insurance, real estate and business services, compared to 20% in the case of Vancouver and 19% in Montreal (Statistics Canada 1994). The 1980s also saw the continuation, if hot the culmination, of the decades-long process of shift of Canadian head offices in finance and other crucial sectors of the economy from Montreal to Toronto. Detailed occupational data from the 1996 census underline the supremacy of Toronto in terms of both the absolute and relative numbers of high-level managerial and professional positions in the financial sector (Statistics Canada 1998). Moreover, for senior management occupations in general, the 1995 earnings of those in Toronto were on average almost 40% higher than those of their Montreal counterparts -- a telling indicator of the relative importance of the two cities in high-level corporate decision-making. The 1980s also saw a continuation and consolidation of the process of restructuring of the occupational composition of the labour force resident in the inner cities not only of Toronto and Montreal but of all of Canada's major advanced tertiary centres. The overall trend has been one of rising skill levels or "professionalisation", resulting both from an increase in the numbers of high-level advanced tertiary sector workers in the inner city and from a decline in the numbers employed in manufacturing (Ley 1996). Despite differences in operational definitions, researchers concur that "urban professionals" or the "professional-managerial class" have been over-represented in the inner city compared to the outer city at least since 1981 and that this over-representation increased during the 1990s (Ley 1996; Rose 1996). It is well-established that a strong presence of advanced tertiary sectors in the central city -- sectors that have a high concentration of professionals in their workforce -- is a necessary condition for the emergence and persistence of the gentrification or embourgeoisement of inner-city neighbourhoods, although it is not a sufficient condition in the absence of other factors that make the inner-city more appealing than the suburbs to members of this group (sec e.g. Bourne 1992; Butler and Hamnett 1994; Caulfield 1994; Ley 1988; Rose 1987). In addition, the increase in numbers of high-income urban professionals and managers has also contributed to the replenishment of long-standing elite areas of Canadian inner cities (e.g. Rosedale, Westmount). The advanced tertiary workers from whom the ranks of gentrifiers and elitearea residents are drawn are, however, not a homogeneous group. As has been previously explored for the Montreal case (Dansereau and Beaudry 1986; Rose 1987; Rose 1996), inner-city professionals display a marked internal differentiation with respect to age, gender, household structure, type of employment and income -- differences likely to have significant implications for the forms taken by inner-city "revitalisation" dynamics (e.g. intensity of pressure on housing sub-markets, nature of demand for services and facilities, neighbourhood social relations). Much less consideration has been given to variations in the characteristics of urban professionals between advanced tertiary centres, although it has been suggested that the truncation of Montreal's supply of the wealthiest echelons of "urban professionals" resulting from file change in its position in the Canadian urban hierarchy is likely to affect the character of its gentrification, as compared with cities with the stature of a national or global command centre (Rose 1996). …
GENDER AND THE SEPARATION OF EMPLOYMENT FROM HOME IN METROPOLITAN MONTREAL, 1971–1981
Journey-to-work studies have repeatedly found that women have shorter work trips than do men. We argue here that this finding can be interpreted in terms of the evolving relationship between (1) the gender division of labor in household production and (2) the position of women in the labor market. We analyze changes in home-to-employment distances in Montreal between 1971 and 1981 and find that, although gender differences in these distances vary over time across occupational categories and economic sectors, the overall gender differential is remarkably stable. We emplore variations in women's work-trip distances by occupational category and examine whether women's short work trips are more related to their household workload or to their positions in the Montreal labor market. The analysis suggests that maritual status, a surrogate for household responsibilities, may not be as strong a correlate of home-to-employment distances in 1981 as it was in 1971, whereas factors related to the labor market, such as...