Evaluation of the Traffic Safety Benefits of a Lower Speed Limit and Restriction of Trucks to Use of Right Lane Only on I-10 over the Atchafalaya Basin: Tech Summary.

摘要

In September 2003, an 11-vehicle crash on I-10 over the Atchafalaya Basin was caused by a truck failing to notice stationary traffic ahead. Five fatalities resulted from the crash, and the Department of Transportation and Research (DOTD) decided to immediately limit trucks to the right lane of traffic and to reduce their speed limit to 55 mph on the elevated section of I-10 over the Atchafalaya Basin. The speed limit for cars was retained at 60 miles per hour. At the time this research study was initiated, no other research study had been conducted to assess the safety implications of the newly implemented policies (reduced speed limit and truck lane restriction) on the Atchafalaya Basin. Although similar policies were implemented in other states such as Texas, the roadway segments on which the policies were implemented had more than two lanes in one direction. A preliminary literature review showed that, although tested, truck lane restriction and differential speed limits had not been implemented before on segments with two lanes in each direction. The Atchafalaya segment of I-10 in Louisiana has two lanes in each direction and operates with both differential speed limits (55 mph for trucks and 60 mph for cars) and truck lane restriction (right lane only).