The reliability of Road User Cost calculations is greatly dependent on good traffic data. Ideally, this information should include 24-hour traffic counts for a full 7-day period, the existing and 20 year projected traffic volumes, the percent of passenger cars and trucks in the traffic stream, and the directional hourly distribution of the facility. The traffic data at the anticipated beginning of construction should be supplied if the existing traffic data is more than two years old before the anticipated contract award date. The following units should be contacted to obtain the best available traffic information.
Transportation Data Development
Intelligent Transportation Services
Major Access Permits
Other pertinent information required to perform Road User Cost calculations includes:
Designers should consider Road User Costs during the scoping and design process as key decision making opportunities occur concerning such items as the following:
This manual provides guidelines and procedures to compute Road User Costs via a modeled approach that provides the analyst with consistent and quantifiable results. Road User Costs are directly related to the current and future traffic demand, facility capacity, and the timing, duration and frequency of work zone induced capacity restrictions.
As long as work zone capacity exceeds vehicle demand on the facility, road user costs are normally not a serious cost to the traveling public. Under such circumstances, the roadway operates under free flow conditions and road user costs are dominated by delay costs in traveling the work zone.
When vehicle demand on the facility exceeds work zone capacity, the facility operates under forced flow conditions and road user costs can be immense. Queuing costs can account for over 90% of road user costs with the majority of the cost being the delay time of crawling through long slow moving queues. Project improvements and work zones that reduce the users actual and perceived costs may be expected to induce traffic to stay on their originally intended or preferred route rather than utilizing other state or local routes. Alternatives available to reduce work zone related road user costs include; carefully selecting the preferred scheme and frequency of rehabilitation activities, restricting the allowable work hours to avoid queuing, adding capacity prior to the development of large traffic demands, accelerating contractor production rates to reduce the overall work zone duration, and utilizing alternative project delivery methods.
The road user costs incurred by the traveling public during project improvements can be extremely high. This manual provides a reasonable measurement of costs incurred by the traveling public to be paid in lieu of timely performance by the contractor in the form of Liquidated Damages.
The quantification of road user costs in both time and money provides the designer with a valuable decision making tool. The examples in this manual illustrate many practical and real life applications.