关键词: |
trucks,lane restrictions,truck lane restrictions,climbing lanes/virginia, tables (data), evaluations, interstate highways, traffic safety/virginia, tables (data), evaluations, interstate highways, traffic safety |
摘要: |
Virginia, like many other states, has used truck lane restrictions on parts of its interstate system in an attempt to improve mobility and safety. The Code of Virginia currently specifies two types of lane restrictions. First, trucks may not travel in the left-most lane of interstates with three or more lanes by direction (1) when the speed limit is 65 mph or higher, (2) along all of I-81, and (3) along interstates in the Virginia Department of Transportation's (VDOT) Northern Virginia District. Second, trucks may not travel in the left lane of two-lane directional interstate segments when their speed is below the posted speed limit; this restriction was enacted in 2007 and was intended to reduce cases of trucks impeding traffic flow on steep grades in the western part of the state. This report describes Phase II of a 2007 study that found that the safety impact of the first type of restriction appeared to be affected by traffic volume. Safety was enhanced on low- volume roads (i.e., annual average daily traffic (AADT) less than 10,000 vehicles per day per lane (vpdpl)) but degraded on high-volume roads (i.e., AADT above 10,000 vpdpl). Given that most of the high-volume interstates investigated were in Northern Virginia, there was a need to re-examine the safety analysis to ensure that the findings were not a product of the growing congestion in the region but rather were attributable to the effects of the truck lane restrictions. The purpose of this study was to provide a detailed assessment of the safety and mobility impacts of Virginia's truck lane restrictions, expanding on the Phase I study. First, crashes on high-volume interstates with three or more lanes by direction noted in the Phase I study were re-examined. Individual crash reports were reviewed, and any crashes that were not influenced by the restriction were removed from subsequent analysis. An empirical Bayes analysis was then used to re-assess safety using the screened crashes. Second, the operational and safety impacts of the restriction on two-lane segments of interstate were examined. Third, the effect of an enforcement campaign on compliance with the restriction for two-lane segments was determined. / Supplementary Notes: See also PB2007-106391. Sponsored by Virginia Dept. of Transportation, Richmond. / Availability Note: Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5301 Shawnee Road, Alexandria, VA, 22312, USA. / NTIS Prices: PC A04 / Corporate Author Code: 089346000 / Classifivation: Unclassified report |