NHTSA Moves on Driver-Impairment Regulation

U.S. safety agency takes anticipated first step in mandating driving-impairment detection for all new vehicles.

The Driver Alcohol Detection System for Safety (DADSS) program is working with the Connecticut Dept. of Transportation to demonstrate impaired-driving prevention technology. (DADSS)

The National Highway Traffic Safety Administration (NHTSA) in mid-December took a significant step to formalize a safety regulation mandating technology to prevent impaired driving in new passenger vehicles. The primary question now is which technology to detect alcohol or drug impairment can get the job done.

Breath-detection technology passively measures alcohol concentration in the driver’s bloodstream with sensors strategically placed in the vehicle cabin. (DADSS)

On December 12, the NHTSA issued its Advance Notice of Proposed Rulemaking (ANPRM) for advanced impaired-driving prevention technology. “This notice helps lay the groundwork for potential alcohol-impairment detection technology standards in all new passenger vehicles when the technology is mature,” the agency said in its release announcing the ANPRM. In 2021, 13,384 people were killed in drunk-driving crashes, NHTSA reported. And the number of states permitting recreational use of marijuana is increasing.

The NHTSA’s ANPRM for impaired-driving prevention – and the eventual safety standard it seeks to establish – is a requirement addressing vehicle and road safety that was written into 2022’s Bipartisan Infrastructure Law. The provision instructed the NHTSA to issue a final rule within three years “prescribing an FMVSS [Federal Motor Vehicle Safety Standard] that requires passenger motor vehicles, manufactured after the effective date of that standard, to be equipped with advanced drunk- and impaired-driving prevention technology.” The date when the technology would begin to be fitted for production vehicles is dependent on a variety of variables not yet finalized.

“Impaired driving crashes are 100 percent preventable – there’s simply no excuse or reason to drive impaired by alcohol or drugs,” said Ann Carlson, NHTSA’s Acting Administrator.

Multiple technology pathways

Steering-column cutaway showing Asahi Kasei-developed prototype alcohol-impairment system; nacelle atop the steering column intakes driver’s breath. (Asahi Kasei)

If an FMVSS is not established within three years, the NHTSA can extend its time allowance, but must annually report to Congress to explain the delay. Once the final rule is established, automakers will have up to three years to begin installing a driver-impairment prevention system as standard equipment.

But there currently is no consensus on which type of technology can or should be used. Most development is directed at breath detection or a spectroscopic (touch-based) approach, but camera vision-based methods also may be viable, as the industry is rapidly maturing machine-vision technology related to driver monitoring required for ADAS functions.

In a late-2022 interview with SAE Media, Brian Brackenbury, director of product line management at Gentex Corp., said, “Vision (impairment detection) is one interesting [method].” At that time, he said there is considerable work remaining on determining accuracy and repeatability standards, regardless of the chosen technology.

The Automotive Coalition for Traffic Safety, through its Driver Alcohol Detection System for Safety (DADSS) program, has been developing both breath- and touch-based impairment-detection technology “designed to measure and precisely quantify blood alcohol concentration (BAC) in drivers and prevent a vehicle from moving. The Program is currently completing the necessary testing to ensure the technologies are fast, accurate, and reliable before being introduced to consumers,” DADSS said at its website.

Cabin of vehicle from the DADSS/Connecticut DOT impaired-driving prevention program demonstrates passive breath-detection technology; note placement of breath intake centered on the steering wheel. (DADSS)

The DADSS program said a first-generation breath sensor was released in December 2021 and the “directed”-breath design currently is in trial deployments in commercial fleets. The first commercial products with the directed-breath system were made available in 2023. A second-generation, passive breath sensor currently is under development by Senseair, the organization said, “and is on target for completion by the end of 2025.” It is believed passive breath-detection technology is most viable for passenger vehicles – DADSS said the current timeline for a fully passive breath sensor to be made available to suppliers and/or product integrators is 2024-2025.

Supplier Asahi Kasei, which specializes in filtration media and electronics among other automotive technologies, in early 2021 displayed its breath-based impairment-detection system. Michael Franchy, director of North American Mobility at Asahi Kasei, told SAE Media in late 2022 that the company was collaborating with DADSS. Volvo, with its 2024 EX90, is among the first OEMs to deploy cabin sensors to monitor potential driver intoxication.

Increasingly sophisticated camera vision may be one method of detecting driver impairment. (Gentex)

But other developers believe a driver-impairment detection system based on breath detection may be flawed, or at minimum difficult to effectively employ in an automotive cabin. A detection method based on a touch from the driver on the start/stop button or the steering wheel shows promise. A spectroscopic touch method using MEMS technology has evolved with several developers, including Joysen Safety Systems.

DADSS is developing a touch-based impairment technology and continues to evaluate and solve issues of integration and deployment in passenger vehicles. For one, the technology likely will need to be coupled with another sensing method to ensure it is the driver touching the sensor. The organization said the timeline has yet to be determined for the touch sensor’s integration into production vehicles.

Alarming rise in deaths

Following the NHTSA’s ANPRM announcement, Rob Strassburger, CEO of the Automotive Coalition for Traffic Safety, said, “We share the desire to commercialize technologies to prevent drunk driving as soon as possible, and remain laser focused on delivering sensors that maintain the highest levels of accuracy, precision and reliability while also protecting consumer privacy. We look forward to reviewing the proposal closely and remain confident the DADSS technology will remain high among those considered for widespread commercial use.”

The day following the NHTSA’s announcement, General Motors CEO Mary Barra also mentioned the agency’s action. Barra said in an interview with the Economic Club of Washington, DC that the technology to detect driver impairment is viable.

Deaths attributed to drunk driving have increased by 35 percent over the past decade, NHTSA said. The 2021 total of 13,384 people killed in alcohol-impaired driving accidents was a 14 percent increase from just the prior year.