Truck-only toll (TOT) lanes, a strategy that provides preferential treatment for truck movements in major freeway corridors, are expected to improve freeway congestion and safety by separating trucks from mixed-flow traffic. However, truck drivers that are unwilling to pay a toll would likely seek non-toll alternative routes, thus increasing arterial congestion and possibly truck-related crashes as well. This paper reports on a crash prediction model that was used to estimate the change in truck-related crashes on parallel arterials caused by the diversion of truck trips from prospective TOT lanes in the Atlanta freeway network. The Atlanta Regional Commission (ARC) travel demand model coded with TOT lanes was applied to generate truck diversions based on route selection of least generalized cost. A negative binomial regression was used to model truck crash prediction onarterial roads. Three variables, vehicle-miles traveled (VMT), truck percent-miles per lane, and the volume-to-capacity (V/C) ratio, are shown to have significant influence on truck-related crashes. Two toll policies ofmandatory and voluntary use of TOT lanes were examined to determine theireffects on truck-related crashes on parallel arterials. It was estimatedthat an average of 8% and 6% reduction in truck crash frequency, respectively, would occur. In addition, mandatory TOT lanes would have a higher decrease in total VMT, reduced truck percent-miles per lane, and improved level of service on parallel arterials compared to those of voluntary TOT lanes because of truck trips attracted to the TOT lanes. As toll rates on the TOT lanes increased, truck-related crashes, truck pollutant emissions and congestion levels on parallel arterials would increase.
Abstract