Damn That Traffic Jam

Many commuters will not be surprised to learn that American cities are not just failing to catch up with the effects of traffic congestion; they are falling further behind each year. And drivers waste an annual total of 5.6 billion gallons of fuel as their engines idle in traffic jams.

These findings are at the center of the 2004 Annual Urban Mobility Report, published Tuesday by the Texas Transportation Institute at Texas A&M University.

Using data from federal, state and local agencies to develop estimates of congestion and mobility within urban areas, the report shows traffic congestion growing across the nation in cities of all sizes, consuming more hours of the day, and affecting more travelers and more shipments of goods than ever before.

Drivers should expect more of the same, the study's authors said.

"We can see pretty clearly what 20 years of almost continuous economic growth can do to us," says co-author Tim Lomax. "If we are lucky enough to sustain this growth and the funding levels and options do not increase from current trends, we should not be surprised if we see even more congestion."

This year's installment of the annual study increases the number of urban areas studied from 75 to 85, and includes all urban areas with a population greater than 500,000. It analyzes the year 2002.

The report finds the annual delay per rush hour traveler has grown from 16 hours to 46 hours a year since 1982.

The annual financial cost of traffic congestion has skyrocketed from $14 billion to more than $63 billion since 1982 – as expressed in 2002 dollars.

The 3.5 billion hours of delay and 5.7 billion gallons of fuel consumed due to congestion are only the elements that are easiest to estimate, the authors said. The effect of uncertain or longer delivery times, missed meetings, business relocations and other congestion results are not included.

The report finds that Los Angeles remains the nation's worst area for gridlock. Drivers in the Los Angeles-Long Beach-Santa Ana region waste an average of 93 hours a year in traffic jams – more than two full work weeks.

San Francisco-Oakland ranked second, with drivers in the Bay Area sitting in traffic some 73 hours a year.

The Washington, DC metropolitan area was third, with drivers sitting in traffic for 67 hours during 2002.

Traffic congestion increased most for drivers in the Dallas-Forth Worth area, where delays soared from 13 hours in 1982 to 61 hours in 2002, earning this area the rank of fourth most congested city in the country.

Although it is a smaller city, Atlanta was fifth. Atlanta drivers sat in traffic for 60 hours during the 2002 driving year.

Travel Time Index (TTI) is a ratio of average peak period to free-flow travel time. The average TTI for all 85 urban areas is 1.37. This means that an average 20 minute trip in free-flow travel time takes almost 27 minutes to complete during rush hours due to heavy traffic demand and incidents.

The report had praise for high occupancy vehicle (HOV) lanes, also known as diamond lanes, bus and carpool lanes, or transitways. Data for the 19 significantly congested corridors studied showed a median decline of 0.20 for the Travel Time Index measure when HOV lanes were used.

"This is equivalent to 10 to 15 years worth of congestion growth in the average area," the report says. "These HOV lanes carry one-third of the peak direction passenger load, providing significant passenger movement at much higher speeds and with more reliable travel times than the congested mainlanes."

The report also found value in operations that attempt to remove crashed and disabled vehicles from the freeway lanes and shoulders; called Freeway Service Patrol, Highway Angel, Highway Helper, The Minutemen or Motorists Assistance Patrol. An incident management program can also reduce secondary crashes – collisions within the stop-and-go traffic caused by the initial incident.