NTSB: Agricultural hours-of-service exemption contributed to fatal crash

March 31, 2023

Tyson Fisher


A National Transportation Safety Board investigation found that a fatal milk truck crash, which was exempt from hours-of-service regulations, could have been avoided with driver fatigue management program.

During a board meeting on Tuesday, March 28, NTSB said a program to manage driver fatigue in agricultural transportation could have prevented a fatal 2021 Arizona Milk Transport truck crash near Phoenix. NTSB noted that collision avoidance technology also could have prevented the crash.

According to NTSB, Arizona Milk Transport operated under an hours-of-service exemption that allows unlimited driving hours for certain agricultural commodities within a 150 air-mile radius.

Investigators said the safety impact of the exemption is unknown, as is the prevalence of its use, and called for more data.

“Generally, motor carriers must make a compelling safety case before regulators will grant them an exemption from safety rules. But, once Congress mandated and then expanded the agricultural hours-of-service exemption, the oversight of the carriers’ fatigue risk largely disappeared,” NTSB Chair Jennifer Homendy said in a statement. “Drivers operating under an hours-of-service exemption are at a greater risk of fatigue: an unacceptable – and avoidable – danger to every road user.”

The crash

On June 9, 2021, an Arizona Milk Transport tractor-trailer hauling milk was traveling east on state Route 202 in Phoenix when the crash occurred.

According to the NTSB investigation, the milk truck crashed into a queue of passenger vehicles that were stopped due to a road closure. The milk truck was going 62-64 mph when the crash occurred. There were no signs of the truck driver slowing down or steering away from the stopped passenger vehicles.

The milk truck partially overrode the car at the end of the traffic queue. Consequently, a series of chain reaction collisions involving six other passenger vehicles ensued. Arizona Milk Transport’s truck then crossed the eastbound travel lanes and struck the median barrier. The tractor-trailer and one passenger vehicle caught on fire.

Four passenger vehicles occupants were killed and 11 occupants were injured. The truck driver was uninjured.

Hours-of-service exemption contributed to fatal crash
The National Transportation Safety Board says a fatal crash involving a milk truck exempt from hours-of-service regs could have been avoided. (Photo from the NTSB)

The investigation

An NTSB investigation of the crash concluded that the Arizona Milk Transport truck driver was fatigued.

Investigators found the driver had less than a six-hour opportunity for sleep the day of the crash and regularly worked 70 to 80 hours per week.

NTSB also discovered that Arizona Milk Transport did not have a program to manage driver fatigue. The investigation revealed that the company “had poor oversight over its drivers and did not enforce its own policies regarding the maximum hours employees could work.”

NTSB made the following recommendations:

  • U.S. Department of Transportation to study the prevalence of driver fatigue in companies operating under the hours-of-service exemption and require them to seek authority to implement a fatigue management program.
  • Milk industry associations encourage their members to adopt a fatigue management program.
  • National Highway Traffic Safety Administration to develop standards for forward collision avoidance systems in commercial vehicles and mandate connected vehicle technology on all new vehicles.

Currently, NTSB has 14 open recommendations related to collision avoidance systems and vehicle-to-everything technologies. The issue is on its Most Wanted List of Transportation Safety Improvements.

NTSB has no regulatory authority. Rather, the board can make recommendations to other transportation agencies with such authority. LL

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