01698291

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The speed limit is one of the essential factors associated with roadway safety. The spillover effect is the tendency of drivers to drive at a higher speed on non - freeway roadways after exiting the freeway. Speed studies were conducted on urban arterial roads with speed limits of 45 mph. These roads are adjacent to freeways with speed limits of 55 mph and 70 mph. A comparison of speed differences between motorists who exited the freeway and those who were already driving on the arterial road was performed. Results showed that the mean speed and 85th percentile of passenger cars on arterials adjacent to 55 mph freeway were 47.34 and 51.08 mph, respectively, while the mean speed and 85th percentile of passenger cars on arterial adjacent to a higher speed 70 mph freeway were 49.52 and 53.35 mph, respectively. Differences in the mean speeds between vehicles exiting from freeways and vehicles already driving on the arterial road were observed at the four sites. This paper provides researchers, policymakers, and engineers with a better understanding of the effects of speed spillover on adjacent roads when determining whether to increase the speed limit on freeways.

This paper was sponsored by TRB committee AHB50 Standing Committee on Traffic Control Devices.

19-02930

English

16p

2019

Transportation Research Board 98th Annual Meeting

Digital/other

Figures; Photos; References (18) ; Tables

Arterial highways; Behavior; Freeways; Highway corridors; Off ramps; Secondary roads; Speed limits; Speeding; Urban highways

Highways; Operations and Traffic Management; Safety and Human Factors

Transportation Research Board Annual Meeting 2019 Paper #19-02930

TRIS, TRB, ATRI

Dec 7 2018 9:51AM