Synthesis of Safety for Traffic Operations - Transports Canada

Legislation and Enforcement
• Taylor Avenue between Lindsay and Wilton Streets had the speed limit reduced
from 60 km/h to 50 km/h in 1982. Taylor Avenue is a four-lane divided arterial
road between Waverly and Wilton Streets, and a two-lane road between Lindsay
and Waverly Streets. Crash rates from 1971 to 1989, inclusive were reported for
the subject section of Taylor Avenue and for all “regional roads” in Winnipeg.
The results are shown in Table 8.2.
TABLE 8.2: Safety Impacts of Speed Limits in Winnipeg, Manitoba
Street
Average Crash Rate
Before After
CMF
Kenaston 6.9 4.6 0.66
All 10.11 7.1 0.70
Taylor 6.7 4.2 0.63
All 9.3 6.8 0.73
Taking into account the general trend of a crash rate reduction on all streets, it would
appear that the speed limit reduction is not as pronounced as the results suggest. A CMF
of 0.95 to 0.86 is more likely. The before and after periods ranged from seven to twelve
years.
Merriam (1993)
Merriam (1993) studied the impacts of speed limit reductions on speeds, speed
dispersion, and safety on rural, arterial roads in the Region of Hamilton-Wentworth.
Three categories of speed limit reductions were examined. The safety impacts were
determined by the change in the collision rate using three years of before and three years
of after data in a simple before-after analysis
Sites were selected for treatment for a variety of reasons. None of the “after” speed
limits were considered warranted based on the 85 th percentile criterion. The results are
shown in Table 8.3.
TABLE 8.3: Safety Impacts of Speed Limits in Hamilton, Ontario
Number Crash Rate Average Speed (km/h)
Speed Limit
of
Change
Before After Before After
Sections
CMF
80 to 60 13 1.47 1.33 76.7 70.9 0.90
80 to 70 12 1.73 1.09 61.2 75.0 0.63
60 to 50 5 2.05 3.07 54.7 64.8 1.50
Crash severity was not investigated.
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