FIGURE 7-4 Concept for reducing the need for additional road right-of-way. SOURCE: FHWA (2005).

reduced and possibly there will be lower insurance costs as the accident rates drop.

Last, during the construction of the truck-only lanes, there would be the ability to update and repair the present roadways at a cheaper cost than going out to maintain or repair the current lanes. This is due to being able to use the material, equipment, and workers to do both jobs.

Financing for truck-only lanes will be difficult to obtain. Tolls from trucks will not pay for construction and maintenance, and public funds and additional taxes would be needed to meet the construction cost of these lanes. The social return on investment has not yet been established.

Furthermore, adequate right-of-way (ROW) is not currently available for the construction of these lanes, so additional land will need to be purchased, and the widening of the right-of-way and the clearing of land may have a negative impact on the environment.

Last, the time that it takes to construct a usable network of truck-only lanes will be several years before any benefits of a better transportation system will be realized. Due to the long time that will be needed, new technologies may not be put into place until some of the lanes are completed.

Congestion pricing refers to variable road tolls (higher prices under congested conditions and lower prices at less congested times and locations) intended to reduce peakperiod traffic volumes to optimal levels. Congestion pricing could take different forms, such as area-wide network pricing on freeways and possibly arterials, “cordon” or area pricing in central business districts, or truck-specific congestion pricing such as the varying time-of-day gate fees implemented at the ports of Los Angeles and Long Beach.

Area-wide congestion pricing is applicable to freeways and major arterials where there is significant congestion. Cordon pricing strategies are only applicable in major urban areas with significant congestion. The limited geographic applicability of these two scenarios limits the fuel reduction potential. Area-wide congestion pricing has greater potential since it is estimated that nearly 30 percent of urban vehicle miles travelled (VMT) occurs at the level of service E (unstable flow) or F (forced or breakdown flow; TRB, 2000). Cordon pricing of metropolitan area central business districts, however, is estimated to affect only 3 percent of total VMT nationwide. Furthermore, evidence suggests that there will be little, if any, overall impact on total truck traffic (as the added costs are likely to be marginal, or the option of moving to the off-peak period is unacceptable), but

FIGURE 7-5 Elevated truck lanes. SOURCE: FHWA (2005).