Washington D.C., Los Angeles, San Francisco, New York City, and Boston rank at the top of the country's worst cities for traffic congestion, according to the most recent urban mobility report from the Texas A&M Transportation Institute.
TTI has lots of ways to measure the costs of congestion, from the number of hours delayed in traffic to the carbon dioxide emission attributed to traffic congestion. This year, the research group introduced a compelling new variable, the Planning Time Index (PTI), which measures the amount of time travelers add on to a trip to meet an important event on time, like a doctor appointment or an airline flight. A PTI value of 3.0 indicates that a traveler should allow three times the actual length of the trip to get their on time--i.e., they would allow 60 minutes for a 20-minute ride in light traffic. (Washington D.C. ranks Number 1 in this category with 5.72, almost three hours designated for a half-hour trip.)
"Washington, D.C., has the dubious distinction of being number one in two areas. It is the capital of partisan gridlock, and now traffic gridlock," observed American Road & Transportation Builders Association President Pete Ruane.
Everyone knows that traffic delays trips, but the report highlights just how variable traffic congestion can be, causing stress and frustration to commuters. The worst trips, the ones you remember, are usually caused by accidents. But other days, the ride can be half as long. "As bad as traffic jams are, it's even more frustrating that you can't depend on traffic jams being consistent from day-to-day. This unreliable travel is costly for commuters and truck drivers moving goods," said Bill Eisele, a TTI researcher and report co-author.
What problems are caused by unreliable traffic patterns, as opposed to more steady gridlock? How can the variability be mediated? How important is transit reliability in easing congestion on the roads? What constitutes "reliable" transit? Are there ways to make congestion patterns more predictable, even if the roads are still crowded? Understanding that budgets are tight, what ideas offer the best bang for the buck in combatting traffic?