Arizona Rail Passenger Association
On Friday, Nov. 13, 1998, the Texas Transportation Institute released its annual report on traffic congestion in major urban areas. The report ranks cities according to a number of factors including how much it would cost to keep up with traffic congestion just through roadbuilding. In response, STPP -- the Surface Transportation Policy Project -- issued an analysis of the TTI data that shows that roadbuilding is an ineffective congestion relief strategy. The STPP study compares metro areas that have added extensive new road capacity with those that have not, and finds no difference between the two groups in the rise in traffic congestion.
Describing STPP's findings on National Public Radio's All Things Considered, Roy Kienitz, Executive Director of STPP, said, "We looked at the cities that added a lot of highway capacity and those that did not, and the only difference between the two was that those in the first group spend a lot of money." For a complete copy of STPP's analysis, visit www.transact.org. TTI's full report, including detailed fact sheets on each city studied and information on recent studies on induced traffic, can be obtained at their web site.
The Surface Transportation Policy Project (STPP) is a non-profit, public interest coalition of over 200 groups devoted to ensuring that transportation policy and investments help conserve energy, protect environmental and aesthetic quality, strengthen the economy, promote social equity, and make communities more livable. For more information about STPP visit their web site or call 202/466-2636.
source for above statistics: Arizona Dept. of Transportation
One lane of roadway -- whether city street or highway -- can carry approximately 1,900 vehicles per hour. This is fairly constant regardless of speed (one lane of a 35mph street has about the same capacity per hour as a 65mph highway) because at higher speeds, drivers leave more space between vehicles. If you recall your driving instructor telling you, "Always leave two seconds between you and the car in front of you," then it is easily calculated that 3,600 seconds per hour, divided by two seconds, equals 1,800 vehicles per hour.
A commuter train can easily carry 500 persons, and with a train every ten minutes (six times an hour), a single-line railroad can easily carry 3,000 persons -- fifty percent more than a single highway lane. Far higher capacities can be achieved through the use of bi-level coaches and fully signaled double track.