As traffic congestion continues to worsen, the time required for a given trip becomes more unpredictable, and researchers now have a way to measure that degree of unreliability, introduced for the first time as part of the annual Urban Mobility Report (UMR), published by the Texas A&M Transportation Institute (TTI).

The Planning Time Index (PTI), a measure of travel reliability, illustrates the amount of extra time needed to arrive on time for higher priority events, such as an airline departure, just-in-time shipments, medical appointments or especially important social commitments.

“We all understand that trips take longer in rush hour, but for really important appointments, we have to allow increasingly more time to ensure an on-time arrival,” says Bill Eisele, a TTI researcher and report co-author. “This unreliable travel is costly for commuters and truck drivers moving goods.”

Researchers say that the most effective way to address traffic congestion is a multifaceted approach, relying on more efficient traffic management and public transportation in addition to new construction. Travel options such as flexible work hours and telecommuting should also be part of the mix.

For more information, visit Mobility.tamu.edu