Dedicated Truck Facilities as Solution to Capacity and Safety Issues on Rural Interstate Highway Corridors

This paper identifies the safety and operational benefits of constructing dedicated truck facilities on a rural Interstate corridor. The Interstate highway segment in the case study is a 164-mi section of I-80 from the Iowa–Illinois border to Altoona, Iowa (an eastern suburb of Des Moines, Iowa). Although many studies have considered constructing an additional lane on freeways and designating it for trucks only, this paper considers the construction of a separate four-lane, limited-access facility for trucks. The I-80 corridor was analyzed with the Highway Economic Requirements Software–state edition (HERS-ST) to measure the performance before and after trucks were removed from the general purpose lanes. Several benefit-to-cost ratios were calculated outside of HERS-ST to determine the economic feasibility (but not the financial feasibility) of constructing dedicated truck lanes. Since there are no similar truck-only facilities in the United States, it is unknown what proportion of motor carriers would choose to use a truck-only facility rather than the mixed-traffic lanes (general purpose lanes), and future policy may or may not require trucks to use parallel truck-only facilities. Therefore, a sensitivity analysis was conducted within the benefit-to-cost analysis to determine the benefits of diverting 100%, 75%, 50%, and 25% of trucks to a dedicated truck facility. At all levels of diversion, the benefits exceed the costs. Although the analysis shows that a truck-only facility is desirable, the policy framework to make such a facility physically and financially feasible does not exist in federal or Iowa policy.