AUSTIN (KXAN) – As Monday afternoon rush hour reached its typical peak, an outbreak of tornadoes bore down on Central Texas on March 21. The unusually powerful storms tore through urban and suburban cores. One twister in Round Rock swirled directly over the crossing of Interstate 35 and State Highway 45. Dramatic footage showed drivers hitting their brakes as a funnel formed and swept across a highway flyover.

GOING IN-DEPTH – LIGHT POLE DAMAGE

Workers also removed a light pole folded in half on the flyover by winds exceeding 100 miles per hour. A TxDOT spokesperson said the type of light pole that broke – called a high mast illumination pole – is made to tolerate certain top wind speeds chosen by location. The poles “are designed for fastest-mile wind velocities of 80 and 100 mph. There are four fastest-mile wind velocity zones in Texas: 70, 80, 90 and 100 mph. We are in the 70-mph zone, so an 80-mph high-mast pole standard was used,” said TxDOT spokesperson Diann Hodges.

Possible damage to a high-use urban bridge led us to ask the Texas Department of Transportation: is that flyover still safe? And with Central Texas getting rocked by both winter and spring storms, is the state checking our bridges as frequently as required?

We discovered TxDOT checked the structural integrity of the Round Rock flyover within hours. The agency closed that bridge to allow engineers to check the structure and removed a folded light pole. Inspectors found the bridge was structurally unharmed.

We also learned TxDOT appears to be checking the state’s bridges within the prescribed timeframes –two years for all highway bridges – outlined by federal National Bridge Inspection Standards.

Inspecting on time

TxDOT’s bridge division oversees inspection of more than 55,000 bridges. The agency’s bridge inspection data is publicly available here.

As we dug into that database, we found fields showing the last inspection date and the required inspection frequency for each bridge. Some quick math showed more than 500 bridges across the state could possibly be overdue for inspections, including many with low sufficiency ratings and classified as obsolete or deficient. We sent that list of bridges to TxDOT. The agency’s bridge division checked and found that the inspections were not, in fact, late.

According to TxDOT, the majority of the bridges that appeared to be overdue for an inspection don’t carry vehicular traffic, such as railroad or utility bridges, so many NBIS standards don’t apply. Those bridges are included in the database “because TxDOT and DMV need that information for rerouting oversized vehicles.”

Also, many of the bridges that appear to be a month or two late had actually been inspected, but reports were being finalized within a 90-day window permitted by federal regulations. There are also some bridges in the database that are closed, yet haven’t been removed, TxDOT said in an email.

It is “not an option” for a bridge inspection to be late, TxDOT said

“TxDOT closely monitors inspection due dates to ensure that inspections are performed on time. Further, the FHWA performs an annual audit to ensure compliance with the NBIS, including on-time inspections,” TxDOT wrote in an email.

KXAN requested that audit from both the state and federal governments, and we will update this report when those are provided.

In 2015, an audit of the Federal Highway Administration’s bridge safety program found it was being effectively overseen. Auditors recommended improvements for documenting work and tracking actions taken to correct deficiencies, according to a U.S. Department of Transportation Office of Inspector General report.

Federal oversight ensures states follow bridge inspection protocol. TxDOT regularly updates its public data with an array of information on each bridge, including a sufficiency rating or if a bridge is obsolete or deficient.

State of Central Texas bridges

KXAN checked into Central Texas bridges in early March and mapped the locations of every bridge in Central Texas, including obsolete and deficient bridges. You can find that report here and see the map we built below.

Obsolete bridges may have out-of-date features – like a deck’s width or approach design – that don’t completely comply with current standards. Obsolete bridges are often older but are structurally sound. Bridges with serious structural problems are classified deficient, according to city and state records.