Questions raised about infrastructure after semi-truck goes off US 75 overpass in Allen, killing driver

The investigation into the death includes the now 7-year-old retaining wall barrier that engineers admit was not designed to contain a vehicle of that size.

ALLEN, Texas — An investigation is underway after a truck driver died when an 18-wheeler went off a highway overpass in Allen, Texas, and officials are also looking into the road’s infrastructure.

The crash happened Tuesday afternoon at the intersection of U.S. 75 and Stacy Road.

Dash camera video from a witness showed the semi-truck plummeting off the U.S. 75 overpass and bursting into flames. Allen police said it appeared the semi-truck collided with another vehicle, which caused it to go off the highway.

The driver of the semi-truck died and was later identified as Gustavo Gomez, 71. The United States Postal Service said Gomez was a contractor who transported mail for the agency.

The investigation into his death includes the now 7-year-old retaining wall barrier that engineers admit was not designed to contain a vehicle of that size.

A spokesperson for the Texas Department of Transportation told WFAA that the section of U.S. 75 at Stacy Road where the accident happened was widened in 2015 and that a new barrier was installed at that time. 

“The purpose of a barrier wall is to prevent drop-offs,” TxDOT said in a written statement, and that “all barrier designs have been crash tested before installation.” The TxDOT spokesperson added that “all fatal crashes are reviewed to determine if any infrastructure actions are warranted.”

The cement F-shaped barrier remained intact despite the impact of the collision. The big rig hit a passenger vehicle, its right tires then rolling up and over the barrier. The vehicle’s fuel tanks ruptured and ignited as the truck and its contents of mail and other correspondence landed upside down on the northbound service road.

William Williams, a research engineer with the Texas A&M Transportation Institute, identified the barrier, or parapet, as a 32-inch TL-4 structure. TL, or Test Level-4, barriers are designed to contain a “single unit truck, car or pickup.” Williams said it was the standard in 2015, but that it was not designed to keep a big rig, in a violent collision like the one in Allen, on the highway.

“It’s not designed and intended to contain and redirect large 18-wheeler vehicles,” he said in a phone interview with WFAA. “It can in some cases. But it’s generally not designed and intended for that purpose on this particular bridge.”

One week ago, also in Allen, the same barrier design did work. An 18-wheeler hit a barrier southbound on U.S. 75 near Bethany and came to rest on top of the cement barrier. The cement parapet kept the truck on the highway but the impact killed the driver.

TL-5 barriers, often seen as center dividers on major highways in heavily traveled areas, are upwards of 50 inches high and reinforced to withstand the impact of a vehicle the size of a big rig truck. TL-6 barriers, as much as 90-inches high, are used to protect against accidents involving heavy tanker truck traffic.

Allen police said their initial investigation into Tuesday’s fatal crash includes a second vehicle. A heavily damaged passenger vehicle, apparently side-swiped by the big rig, was towed from the scene and the driver was questioned, but not arrested.