User Costs and Calculations
​The cost of congestion is the value of the extra time and fuel that is consumed during congested travel. The value of time is estimated for drivers. The fuel costs for passenger vehicles and trucks are the per-gallon average price for each state. Most commonly, the value of a person’s time is derived from the perspective of the individual’s value of their time, rather than being based on the wage rate. Only the value of truck operating time is included; the value of the commodities is not.
 
References
TTI Article: What Does Congestion Cost?
Congestion has several effects on travelers, businesses, agencies and cities. One significant element is the value of the additional time and wasted fuel. The top 14 urban areas include about two-thirds of the delay estimated for 2005, and the top 20 areas account for over 75 percent of annual delay.
What Does Congestion Cost.pdfWhat Does Congestion Cost.pdf

Minnesota DOT Benefit Cost Analysis
This document is intended to provide guidance to perform benefit-cost analysis for highway projects. The guidance includes: background information on benefit-cost analysis and how it may fit into the project development process; discussion of economic terms and principles; review of relevant stages in conducting a benefit-cost analysis for highway projects; advice on using benefit-cost results.
Minnesota DOT Benefit Cost Analysis

AAA Crashes vs. Congestion: What's the Cost to Society?
When American motorists talk about transportation problems, they generally key in on traffic. Snarled highways, epic commutes, and gridlocked business and commercial districts mar our suburban existence, weighing heavily upon our elected leaders, our policymakers, and our families. Yet there's a more costly problem to be addressed on America's roads: motor vehicle crashes.
AAA Crashes vs. Congestion: What's the Cost to Society?