Safety Impacts of a Freeway Managed Lane Strategy: Inside Lane for HOV Use and Right-Shoulder Laner as a Travel Lane during Peak Periods

Authors: 
Jung-Taek Lee, Randy Dittberner, Hari Sripathi
Publisher: 
Virginia DOT
Pages: 
20
Abstract: 
This paper presents the results of a safety analysis of a freeway managed-lane strategy, i.e., a time-of-day managed lane strategy that concurrently allows use of the inner-left lanes by high-occupancy vehicles and use of right shoulders as general-purpose travel lanes during peak hours. Recent three-year crash data and corresponding AADT volumes and lane-type specific AADT volumes were identified for various lane types, including the inner-left lanes for HOV-only during peak hours, general-purpose, right shoulder lanes, and all the lanes as a whole. Negative binomial regression models were used to estimate the effect of this traffic operations system and other factors relevant to crash frequency. The negative binomial regressional model analyses present no evidence that the interst factors, includ ng the managed-lane strategy during peak hours, AADT volumes, merging and diverging influence areas, weather, light conditions, and existence of pull-off areas, affect the crash frequency when aggregated across all lanes. The variable AADT volumes in the specific analysis of general-purpose lanes appears to be significant and shows about a 2% increase in weekday crashes for each increase of 1,000 vehicles per day in the AADT range of 50,000 to 83,000 vehicles per day. Right shoulder specific analysis also shows that motorist behaviors at the merge and diverge areas during adverse light conditions are significant and shows about 38% increase in crashes in these areas. The managed-lane strategy does not appear to be significant to the crash frequency in the inner left lanes for HOV, general-purpose lanes, or right shoulders