How did the I-35W 133-vehicle pileup on icy roadways in February 2021 happen?
Final answers to what caused the 133-vehicle pileup on Interstate 35W that killed six people in 2021 are a part of the report the National Transportation Safety Board released Thursday.
The incident was on an icy patch of southbound TEXPress lanes near Northside Drive in Fort Worth.
When did the I-35 pileup happen?
The 133-vehicle pileup happened on Feb. 11 around 6 a.m.
NTSB documents released in January included a timeline of events and outlined where and when roads were treated to prevent ice.
Feb. 9, 2021 at about 10:12 a.m.: North Tarrant Express Mobility Partners applies brine solution to the southbound toll lanes.
Feb. 11, 2021 at about 3 a.m.: A crash occurs on the northbound general use lanes of I-35W, about five miles north of the crash site. The crash was partially due to icy conditions on an elevated bridge, according to the report.
Feb. 11., 2021 at about 3:20 a.m.: North Tarrant Express Mobility Partners dispatches maintenance crew members to the northbound crash site. They used salt to “spot treat” southbound and northbound toll lanes and general use lanes — a process that was complete around 4:43 a.m. Around 3:40 North Tarrant Express Mobility Partners also activated seven dynamic message signs within 8.3 miles of the crash.
Feb. 11., 2021 at about 4:40 a.m.: North Tarrant Express Mobility Partners detect moisture near the area where the crash later occurred and send maintenance crew members to treat the U.S. 287 entrance ramps to northbound toll lanes and general use lanes, and the Texas 280 entrance ramps to northbound and southbound general use lanes with salt. Treatment was done at about 5:20 a.m.
Feb. 11., 2021 at about 6 a.m.: The pileup crash occurs in the southbound I-35W toll lanes near the exit to Northside Drive.
How many deaths and injuries were caused by the pileup?
The crash involved a combination of commercial and passenger vehicles and covered a segment of roadway approximately 1,100 feet long, the Star-Telegram previously reported.
Six people were fatally injured. Two of the fatally injured people were pedestrians who exited their vehicles and were struck on the road. The other fatally injured people had remained inside their vehicles. Thirty-six vehicle occupants were transported to area hospitals for treatment of their injuries.
What caused the pileup?
The final NTSB investigation report will include analysis, findings, recommendations and probable cause determinations related to the crash.
In April 2021 the NTSB released a preliminary report that found the company responsible for preventing ice on the TEXPress lanes had applied a brine solution to the roadway 44 hours before the crash, the Star-Telegram previously reported.
According to the document from he North Tarrant Express Mobility Partners, the average vehicle speed was 65 mph in the right lane and 82 in the left 15 minutes before the collision, but speeds topped 100 mph at one point less than 15 minutes before the accident.
What preventative measures have been taken since the pileup?
The Star-Telegram previously reported that the North Tarrant Express Mobility Partners took a number of preventative steps since the 2021 crash which included training updates and increasing the number of vehicles available for maintenance.
Other steps included increased salt storage by over 400 tons, a new weather forecast vendor for localized forecasts and sensors to capture air and pavement temperatures.