Deficient Monitoring of Icy Roads, Speeding, Leads to I-35W Multi-Vehicle Crash


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​​​WASHINGTON (March 23, 2023) – The company responsible for the operation and maintenance of Interstate 35 West (I-35W) in Fort Worth, Texas, failed to effectively monitor and address icy roadway conditions during a 2021 winter storm, contributing to a multi-vehicle crash, the NTSB said Thursday.

The crashes occurred on Feb. 11, 2021, on an elevated section of the southbound toll lanes of I-35W and involved commercial and passenger vehicles. As a result of the crash, six people died and 36 others were transported to area hospitals. 

The crash sequence began at 6:04 a.m., when a vehicle traveling near the Northside Drive exit struck the concrete barrier on the right side of the toll lanes, NTSB investigators found. Other vehicles in the southbound toll lanes then began to slide, spin and strike the barriers. At 6:13 a.m., a large truck crashed into some of the disabled vehicles that were blocking the travel lanes. Other vehicles that were unable to stop led to a complex, multivehicle crash blocking all southbound toll lanes.

In the days before the crash, the area had experienced 36 consecutive hours of below-freezing temperatures. 

North Tarrant Express Mobility Partners Segment 3 (NTEMP S3), the company responsible for operations and maintenance on the I-35W right of way, had pretreated the two southbound lanes with a liquid brine solution 44 hours before the crash. On Feb. 11, company employees spot-treated some sections of roadway with salt, but they did not treat the elevated portion of I-35W where the multi-vehicle crash occurred. Maintenance crews drove north on I-35W about 45 minutes before the crash and visually checked the road, but they detected no moisture and applied no salt. NTSB investigators found that NTEMP S3’s roadway monitoring process was deficient because, as precipitation and freezing temperatures continued and conditions deteriorated on the morning of Feb. 11, company personnel did not identify the elevated portion of I-35W as needing additional de-icing treatment, which left the roadway surface icy.

NTSB investigators also found that drivers traveling at speeds too fast for winter weather conditions contributed to the severity of the crash. The roadway has a 75-mph speed limit.

As a result of the investigation, the NTSB is recommending that Texas install variable speed-limit signs, add sensors to reduce response times to weather-related hazardous road conditions and provide training to Texas toll road facilities on how to better respond to winter storms.

The NTSB also reiterated previous recommendations in favor of automated speed enforcement and increased connected vehicle technology deployment.

The full highway investigative report is available on the NTSB’s website​.    

To report an incident/accident or if you are a public safety agency, please call 1-844-373-9922 or 202-314-6290 to speak to a Watch Officer at the NTSB Response Operations Center (ROC) in Washington, DC (24/7).