HOUSTON – The Texas Department of Transportation is considering raising the height of a pair of Houston-area bridges prone to getting hit by large trucks.

According to TxDOT records, the Houston Avenue bridge has been hit 21 times over the last four years, while its counterpart, the Waco Street bridge, has been hit 11 times.

Both of these bridges span I-10, and a TxDOT spokesperson said big rigs traveling westbound tend to hit the Waco Street bridge, while those traveling eastbound tend to hit the Houston Avenue bridge.

"It's an inconvenience of the traveling public, but it's also costly," Perez said.

State records show TxDOT estimates it will spend $142,620 for emergency maintenance work on the Houston Avenue bridge and another $98,200 on the Waco Street bridge.

"It's important to know how high your load is," Perez said.

Signage on the Houston Avenue bridge reads 14.3 feet, and a sign on the Waco Street bridge reads 14.4 feet. Both were within state guidelines at the time the structures were built, but are shorter than the more current standard of 16.5 feet. The state is also considering making the minimum height for bridges spanning freight corridors 18.5 feet. According to information on the Federal Highway Administration's Office of Freight Management and Operations website, there are no federal height requirements for commercial motor vehicles. However, states do set their own height requirements.

According to the Texas Department of Public Safety, CMVs are to be no higher than 14 feet.

"So what's happening is these over-height vehicles are coming through here, they're traveling on the outside lane," Perez said.

Perez said a bridge's lowest point is typically on the outside lanes. Since I-10 runs coast-to-coast, Houston sees a lot of trucks from out-of-state that come in all shapes and sizes.

TxDOT has been trying to address this problem by installing sensors on the eastbound lanes near Wirt Road and on the westbound lanes near Mercury. If the sensors detect an 18-wheeler is too tall to clear one of the upcoming bridges, a signboard flashes a warning to the driver and instructs the person to find an alternate route. TxDOT records show the alarms on the eastbound side were triggered more than 6,000 times since the beginning of the year and more than 3,100 times on the westbound side.

Recently, TxDOT has installed even more signs closer to these bridges, warning drivers of the clearance level. TxDOT officials are also asking Houston police to help stop those drivers who do not heed the over-height warnings before they reach one of these bridges.

TxDOT officials said they are considering raising the height of those and other bridges in the area as part of the North Houston Highway Improvement Project. However, TxDOT officials said it could take five to 10 years for those plans to come to fruition.