The social problem called traffic congestion results when the number of vehicles using the existing transportation facilities and systems serving a country, city, community, or other area (infrastructure) exceed that infrastructure's carrying capacity. Characterizing traffic congestion are a decrease in the actual speed a vehicle may travel regardless of posted speed limit, increased travel time, and/or an increase in the amount of time it takes to enter an existing flow of traffic. The amount of traffic congestion depends on both recurring (regular rush hour traffic) and nonrecurring (congestion due to special road construction) variables.

According to the U.S. Department of Transportation Federal Highway Administration (FHWA), since 1982 traffic congestion has increased in all cities across the United States. In 2003, the Texas Transportation Institute studied 85 U.S. urban areas and found that traffic congestion caused an estimated 1.9 billion hours of delay and cost an estimated $63 billion in wasted time and fuel. Solutions to this overall increase in traffic congestion include building more roads and highways, using the existing infrastructure more efficiently, and a more controversial measure, the privatization of U.S. highways.

The FHWA officially measures traffic congestion in terms of a travel time index and delay. The travel time index consists of the ratio of the time it takes to travel during peak infrastructure use to the time it takes to travel the same distance when traffic flows freely. For example, if a commuter must spend 35 minutes traveling from point A to point B during a holiday, but only spends 20 minutes traveling that same distance on a regular weekday, that travel time is calculated by dividing 20 by 35, and travel time is 1.75 in the travel time index. This measure accounts for both reoccurring (i.e., late afternoon commuter traffic) and incidental (i.e., traffic accidents) travel interruptions. The Texas Transportation Institute found that the Los Angeles-Long Beach-Santa Ana, California, urban area had a travel time index of 1.84, while the Corpus Christi, Texas, urban area had a travel time index of 1.04, indicating that the former urban area experienced more congestion than the latter.

The delay measure consists of annual hours of delay (hours of extra travel time due to congestion), annual delay per capita (hours of extra travel time divided by area population), and annual delay per road user (extra travel time hours divided by peak period road users). For example, the Texas Transportation Institute's regular analysis of traffic congestion in the largest 85 urban areas demonstrated that American travelers lost 47 hours in annual hours of delay, up from 16 annual hours of delay in the 1982 traffic congestion survey.

In addition to the time travel index and delay, recently the FHWA began measuring travel time reliability, a measure of variation in travel time taking into account unpredictable congestion (i.e., a traffic light malfunctions, leaving cars backed up at an intersection until police arrive to direct traffic). Travel time reliability varies over time because conditions such as the weather and work zones vary over time. Traveling in an area with highly variable travel time causes travelers to leave extra time, or buffer, in their schedule for possible delays; even though at worst this may result in a traveler arriving early instead of on time, this is still time the traveler might have used more productively elsewhere.

Officials measure travel time reliability in terms of how travel time varies hour to hour or day to day. For example, a traveler might report that it takes 30 minutes to reach a destination with no traffic or construction, but with an active work zone on the road it takes 1 hour and 30 minutes. Travelers must consider this unpredictable event when planning their journey or risk arriving at their destination late.

References:

1) Arnot, Richard. 2005. Alleviating Urban Traffic Congestion. Cambridge, MA: MIT Press.

2) Downs, Anthony. 2004. Still Stuck in Traffic: Coping with Peak-Hour Traffic Congestion. Washington, DC: Brookings Institution Press.

3) Federal Highway Administration. 2005. "Traffic Congestion and Reliability: Trends and Advanced Strategies for Congestion Mitigation." Washington, DC: Federal Highway Administration.

4) Kay, Jane Holtz. 1998. Asphalt Nation: How the Automobile Took Over America and How We Can Take It Back. Berkeley, CA: University of California Press.

5) Motavalli, Jim. 2003. Breaking Gridlock: Moving toward Transportation That Works. San Francisco: Sierra Club.

Free term papers are not written to satisfy your specific instructions. You can use our professional writing services to buy a custom written research paper, term paper, or essay on Controversial Topics at affordable price. CustomTermPapers is the best solution for those who seek help in writing term papers, essays, and research papers related to Controversial Topics and other relevant topics.