Perhaps not surprisingly, the Feds are in favor of varying tolls based on demand, otherwise known as "congestion pricing."
From a Stamford (CT) Advocate story:
Other cities worldwide use [congestion pricing] successfully, and other transportation systems, such as airlines and railroads, already charge varying rates based on peak hours, [Patrick] DeCorla-Souza [program manager for the Federal Highway Administration's congestion pricing initiative] said at a meeting at Westport [CT] Police Department headquarters organized by the South Western Regional Planning Agency.
"People understand that at certain times during the year, certain goods and services are more valuable," DeCorla-Souza said at the event, attended by about 30 municipal leaders and legislators from Fairfield County. "The idea now is to help them understand it in the transportation arena."
Previously: Integrated traffic strategy