Safety Impact of Truck Lane Restrictions on Multilane Freeways

Abstract

Many states have implemented truck lane restrictions in an attempt to improve safety and mobility on freeways. These restrictions typically prohibit trucks from traveling in the median (left-most) lane of multi-lane highways; the restriction potentially increases passing opportunities and reduces negative interactions between slow-moving trucks and faster-moving vehicles. Virginia has restricted trucks from the median lane of some interstates with three or more lanes by direction since 1997, but no systematic evaluation of the safety impact of the restrictions has been conducted. Evaluations of similar restrictions in other states have yielded contradictory findings, but those studies often used a limited data set. An empirical Bayes’ analysis of Virginia's restrictions was performed by using 6 years of crash data from 22 sites with restrictions and 16 similar sites without restrictions. The analysis showed that a breakpoint in safety performance occurred around 10,000 vehicles per day per lane. Facilities where the volume was below this threshold had significantly fewer crashes than anticipated, averaging a 13% reduction in total crashes and a 32% reduction in fatal and injury crashes. Sites where the volume exceeded this threshold had increases in total crashes and fatal or injury crashes of 28% and 23%, respectively. A detailed analysis of crashes on the higher-volume roads was conducted to screen out crashes in which the restrictions likely played no role. That analysis showed that the number of truck-involved crashes was still significantly higher than predicted, indicating that safety on higher-volume roads may be negatively affected by truck lane restrictions.

Occupational fatalities among driver/sales workers and truck drivers in the United States, 2003–2008

“…Large companies may have different work conditions and safety cultures than small companies. Other environmental factors may include road condition, traffic condition, hours‐of‐service regulations, and other relevant safety regulations [Kanazawa et al, ; Chen, ; Stigson et al, ; Fontaine et al, ; Hanowski et al, ; McKnight and Bahouth, ; Chen and Chen, ]. Effective prevention efforts should address these risk factors that are associated with drivers, vehicles, and environments.…”

Motorway Safety in Korea

“…Several studies have been conducted to measure the effectiveness of restricted lane use on motorways in the United States (Liu and 2007;Qi, 2009). There is evidence that truck-only lanes may negatively affect safety on motorways with a higher traffic volume (Fontaine et al, 2009). An analysis of Virginia's truck lane restriction showed that there is a breakpoint in safety performance at approximately 10 000 vehicles per day per lane.…”

Freeway Truck Lane Restriction and Differential Speed Limits

“…Mannering et al reported that the truck-involved crash rate increased when trucks were restricted from the leftmost lane on an uphill freeway with three lanes in each direction, because the main cause of the crashes at that particular site was changing lanes to the right (17 ). Fontaine et al performed an empirical Bayes analysis to evaluate the safety impact of Virginia's truck lane restrictions by using 6 years of crash data from 22 sites with restrictions and 16 similar sites without restrictions (18). They stated that the safety performance was significantly affected by the traffic volume and that the restrictions likely played no role.…”