Oklahoma officials are blaming the increasing number of tractor-trailers for highway maintenance problems.

According to the Associated Press, the number of tractor-trailers traveling the state’s roads doubled between 1996 and 1999, thanks to the intersections of Interstate 40 and Interstate 35, both heavily traveled truck routes.
The Oklahoma Transportation Department says one tractor-trailer causes the same wear as about 1,000 cars, leading to more than 3,000 miles of deficient highways and bridges.
However, the problem may be largely because not enough of the tax revenue paid by trucks and other vehicles actually goes toward highway maintenance. A study by The Road Information Program ranked Oklahoma second in the nation in 2001 for the amount of money taken from vehicle tax revenues and used for other purposes. Only about 20 cents of each dollar goes to the state Transportation Department, a DOT spokesperson told the AP. The rest goes to city and county roads and other uses not related to roads.