California Department of Transportation


Q How congested are the freeways in California?

According to a 1995 State Highway Congestion Monitoring Program report (the most recent year available), there was a total of 315,476 VHDPD (vehicle hours of delay per day) on urban area freeways in California due to "recurrent" congestion. Recurrent congestion is defined as a condition lasting for 15 minutes or longer where travel demand exceeds freeway design capacity. That typically means freeway speeds were 35 mph or less during peak commute periods on a typical incident-free weekday. "Non-recurrent" congestion is defined as backups caused by special circumstances, such as accidents, stalled vehicles, sporting events, etc. Studies show that non-recurrent delay can be equal or greater than recurrent delay. The report found that recurrent and non-recurrent congestion combined meant California motorists in 1995 used an extra 1.1 million gallons of fuel per day due to urban freeway congestion. The increased travel time and extra fuel cost motorists about $5.9 million per day.