California Experience with Insider Shoulder Removals

Authors: 
Thomas Urbank and Carlos R. Bonilla
Publisher: 
Transportation Research Board
Pages: 
10
Report Number: 
1122
Abstract: 
The problem of increasing freeway corridor capacity in a safe and cost-effective manner is becoming more difficult. One method to provide additional mixed-flow or high-occupancy vehicle (HOV) capacuty is to remove shoulders and narrow lanes. In this paper, the California safety experience with inside shoulder removals that for each site generally resulted in either no signifcant change or a significant reduction in overall accident rates is documented. Congestion reduction appears to be the cause of the accident rate reductions. The analysis also suggests that accident severity is not affected; the only significant change in accidents is a reduction in noninjury accidents.