What are the two main types of congestion?
Recurring congestion, which occurs on a regular basis, typically in the peak hour, is caused by heavy demand trying to use a facility at the same time. Nonrecurring congestion is caused by random, but not infrequent, events that disrupt traffic flow, such as vehicle breakdowns, accidents, construction work zones and weather. Nonrecurring congestion is generally credited with causing half of the total roadway system delay.
