In 1957, Lethbridge council met to discuss the expansion of Highway 3 between Lethbridge and Coaldale to a divided highway.
 Highway Minister Gordon Taylor in 1958 confirmed that Alberta would complete the project in the "near future" but did not have a definite timeline.
 Coaldale voiced opposition to an upgraded highway bypassing the town, fearing economic losses as traffic would be diverted away from the town.
 Citing safety and efficiency for motorists, Taylor stated that the province would prefer for major highways to not travel through towns, but extra mileage would not be created to accomplish this.
 Twinning work had been completed by the mid-1960s, and the divided highway bisected Coaldale.
 Work began in 1963 to upgrade the highway between Coaldale and Barnwell so it could carry loads up to 72,000 pounds (33 metric tons).
 E.C. Lonsdale, the chairman of the Lethbridge Chamber of Commerce, stated that the region was at an economic disadvantage until the upgrade was completed.
 The final alignment for the upgraded highway through Barnwell had been confirmed by March 1966 with construction beginning shortly thereafter.

In 1965, the Chamber pressed Taylor for further upgrades to the highway, including safety improvements to intersections and the construction of adequate shoulders.
 Taylor stated that the province was doing its best to improve the road, but funds were being spread among other important highway projects in the province.
 "Meanwhile, you must not forget you have a completely black topped road here, one that is equal to the best roads in some of the other provinces and the United States," Taylor said.
 Nevertheless, the Chamber was still concerned about the condition of the road, particularly in the Crowsnest Pass region where mountainous terrain and steep grades were making upgrades difficult.
 There was also concern about the diversion of traffic from Highway 3 to the Trans-Canada Highway, which would have a negative effect on the economies of southern Alberta municipalities.

Highway 3 underwent major realignment in the Lethbridge area beginning in 1966.
 The existing route along Westside Drive and Bridge Drive was to be replaced by a new four-lane expressway to the north, requiring new bridges over the CPR tracks and an interchange at Highway 25.
 Most of the interchange was built in 1966, but construction of the bridge carrying Highway 25 over the new Highway 3 lagged behind and opened the following year.
 The twin bridges carrying the new Highway 3 over the CPR tracks west of Lethbridge also opened in 1967, as did a trumpet interchange further east at Bridge Drive on the west bank of the Oldman River.
 The existing two-lane bridge over the Oldman River that had been constructed in 1946 was widened to four lanes, and a partial interchange at 5 Avenue N built by 1968 completed the realignment.
 Highway 3 was now twinned from Monarch to Coaldale.

In Medicine Hat, plans were presented to city council for an expressway upgrade to the Trans-Canada Highway in September 1968.
 The upgrade would include the construction of a diamond interchange at the existing intersection with Gershaw Drive (Highway 3) and the widening of Gershaw to a four-lane road.
 The interchange had been constructed by summer 1976, delayed several weeks by unstable terrain necessitating steel beams to supplement the concrete piles for the bridge.

Planning began in 1970 to establish a 4-lane corridor for Highway 3 near Crowsnest Pass.
 A route north of Coleman was first selected, later changed to the south in 1973 to avoid developed residential areas on the north side of Coleman.
 By the end of the decade, both the province and local municipality had endorsed the route.
In the mid-1980s, the municipality asked the province to reconsider a route further to the north of Coleman, but it was deemed to be at an unacceptable grade.
 The alignment to the south of Coleman and Sentinel planned in the 1970s remains the preferred option for future upgrading.
In 1957, Lethbridge council met to discuss the expansion of Highway 3 between Lethbridge and Coaldale to a divided highway.  Highway Minister Gordon Taylor in 1958 confirmed that Alberta would complete the project in the "near future" but did not have a definite timeline.  Coaldale voiced opposition to an upgraded highway bypassing the town, fearing economic losses as traffic would be diverted away from the town.  Citing safety and efficiency for motorists, Taylor stated that the province would prefer for major highways to not travel through towns, but extra mileage would not be created to accomplish this.  Twinning work had been completed by the mid-1960s, and the divided highway bisected Coaldale.  Work began in 1963 to upgrade the highway between Coaldale and Barnwell so it could carry loads up to 72,000 pounds (33 metric tons).  E.C. Lonsdale, the chairman of the Lethbridge Chamber of Commerce, stated that the region was at an economic disadvantage until the upgrade was completed.  The final alignment for the upgraded highway through Barnwell had been confirmed by March 1966 with construction beginning shortly thereafter.
In 1965, the Chamber pressed Taylor for further upgrades to the highway, including safety improvements to intersections and the construction of adequate shoulders.  Taylor stated that the province was doing its best to improve the road, but funds were being spread among other important highway projects in the province.  "Meanwhile, you must not forget you have a completely black topped road here, one that is equal to the best roads in some of the other provinces and the United States," Taylor said.  Nevertheless, the Chamber was still concerned about the condition of the road, particularly in the Crowsnest Pass region where mountainous terrain and steep grades were making upgrades difficult.  There was also concern about the diversion of traffic from Highway 3 to the Trans-Canada Highway, which would have a negative effect on the economies of southern Alberta municipalities.
Highway 3 underwent major realignment in the Lethbridge area beginning in 1966.  The existing route along Westside Drive and Bridge Drive was to be replaced by a new four-lane expressway to the north, requiring new bridges over the CPR tracks and an interchange at Highway 25.  Most of the interchange was built in 1966, but construction of the bridge carrying Highway 25 over the new Highway 3 lagged behind and opened the following year.  The twin bridges carrying the new Highway 3 over the CPR tracks west of Lethbridge also opened in 1967, as did a trumpet interchange further east at Bridge Drive on the west bank of the Oldman River.  The existing two-lane bridge over the Oldman River that had been constructed in 1946 was widened to four lanes, and a partial interchange at 5 Avenue N built by 1968 completed the realignment.  Highway 3 was now twinned from Monarch to Coaldale.
In Medicine Hat, plans were presented to city council for an expressway upgrade to the Trans-Canada Highway in September 1968.  The upgrade would include the construction of a diamond interchange at the existing intersection with Gershaw Drive (Highway 3) and the widening of Gershaw to a four-lane road.  The interchange had been constructed by summer 1976, delayed several weeks by unstable terrain necessitating steel beams to supplement the concrete piles for the bridge.
Planning began in 1970 to establish a 4-lane corridor for Highway 3 near Crowsnest Pass.  A route north of Coleman was first selected, later changed to the south in 1973 to avoid developed residential areas on the north side of Coleman.  By the end of the decade, both the province and local municipality had endorsed the route. In the mid-1980s, the municipality asked the province to reconsider a route further to the north of Coleman, but it was deemed to be at an unacceptable grade.  The alignment to the south of Coleman and Sentinel planned in the 1970s remains the preferred option for future upgrading.
Alberta Highway 3