From WaPo: Traffic Cure Worsens the Pain
"So much traffic clogs Washington area roads that Cox Communications has to use 20 percent more trucks here to serve the same number of customers as in other regions. Metro has to add an average of 10 buses a year, at $521,980 a pop, just to maintain rush-hour schedules that have slipped because of congestion." ... thereby causing more congestion.
"A truck and driver stuck in traffic costs $65 per hour, according to [Giant Food] spokesman Barry Scher."