Skip to main content

First national study of US travel time reliability

Texas Transportation Institute (TTI) has published the 2011 Congested Corridors Report, the first nationwide effort to identify reliability problems at specific stretches of US highway responsible for significant traffic congestion at different times and different days. Researchers noted that the corridors included in the report were identified by the data itself.
April 30, 2012 Read time: 2 mins
RSS2347 Texas Transportation Institute (TTI) has published the 2011 Congested Corridors Report, the first nationwide effort to identify reliability problems at specific stretches of US highway responsible for significant traffic congestion at different times and different days. Researchers noted that the corridors included in the report were identified by the data itself.

5367 INRIX, a leading provider of traffic data and analytics, originated the corridor approach, using 10 hours of congestion per week to define a starting point for a congested corridor. To be considered a “corridor,” according to the Inrix standard adopted for this report, congestion should impact a freeway segment at least three miles long.

“Until now, we’ve been able to measure average congestion levels,” says TTI research engineer Bill Eisele, “but congestion isn’t an ‘average’ problem. Commuters and truckers are understandably frustrated when they can’t count on a predictable trip time from day to day.”

The report describes congestion problems in 328 seriously congested corridors over a variety of times — all day, morning and evening peaks, midday, and weekends. Not only were these roads found to have more stop-and-go traffic than others, they were also much less predictable — “so, not only does it take longer, commuters and truckers have a difficult time knowing how much longer it will take each time they make the same trip” said co-author David Schrank.

The 328 corridors, while accounting for only six per cent of the nation’s total freeway lane-miles in the US and 10 per cent of the traffic, account for 36 per cent of the country’s urban freeway congestion.

As the first look at travel time reliability across the US, researchers believe that the report can be useful in determining where transportation system improvements will have the greatest impact.

Click here for a copy of the report.

For more information on companies in this article

Related Content

  • Safety measures aid workzone accident reduction
    February 20, 2012
    Everyone connected with the highway industry is involved in the efforts to cut down the number of work zone accidents. Patrick Smith reports. A few months ago, as road work resumed on America's highways and bridges, US Transportation Secretary Ray LaHood called on drivers to use extra caution in work zones. At the same time he commended the success in reducing overall roadway fatalities in each of the last seven years.
  • Permanent DMS in work zones
    February 9, 2012
    Forty-four state agencies currently rely on Daktronics for a total of more than 3,500 dynamic message signs (DMS) to provide important information to motorists. As soon as a new construction project begins, approaching motorists need to know exactly what to expect. Permanent DMS provide the information ahead of time, ahead of the congestion.
  • Iteris launches iPerform to measure and manage transportation networks
    April 26, 2012
    Iteris has introduced the iPerform information management solution that utilises all available data resources to provide effective performance analysis and prediction. The software can fuse information from a full spectrum of sources including roadway sensors as well as weather and other traffic related data. Moreover, Iteris says it provides this valuable information for not only freeways, but for arterials and multi-modal forms of transportation as well. "With the increased emphasis on accountability in t
  • Chile’s new urban highway link
    May 2, 2022
    Nestling in a valley beside the Andes mountain range, Santiago has a growing population and has suffered from increasingly heavy congestion in recent years, requiring a new urban road link for which safety has been set as a priority for drivers - *iRAP reports