Americans drove less but drove faster during the pandemic as there were fewer vehicles on the road, often with disastrous results. Now it seems they may have had some technological help.
More and more drivers are using adaptive cruise control, or similar technologies, to speed, according a new study from the Insurance Institute for Highway Safety. Using the technology to go faster isn’t a “safer” way to speed, in fact, it undermines its purpose entirely.
“ACC does have some safety benefits, but it’s important to consider how drivers might cancel out these benefits by misusing the system,” said IIHS Statistician Sam Monfort, the lead author of the paper. “Speed at impact is among the most important factors in whether or not a crash turns out to be fatal.”
Set it and forget is dangerous
The study revealed drivers are “substantially” more likely to speed when using adaptive cruise control or some other form of partial autonomous driving technology that uses lane centering, if ACC isn’t available. Typically, these advanced driver assistance systems don’t limit the speed setting.
Often systems like Tesla’s Autopilot, Cadillac’s Super Cruise and other semi-autonomous technologies lull vehicle owners into a false sense of security, forgetting that rule No. 1 for these technologies is that the driver must remain alert and aware at all times.
Speeders, in the set-it-and-forget-it scenario, count on the technology’s ability to slow the vehicle down — even stop it in some cases — and then resume the original excessive speed. Lane centering adds to their comfort level. However, there are many situations these ADAS technologies aren’t equipped to handle and that’s when the trouble starts.
While it’s unclear what role ADAS may have played, preliminary data indicates as many as 42,060 Americans died in motor vehicle crashes last year – an 8% increase from 2019. The death rate surged 24% on a per-mile basis – the biggest year-over-year jump since 1924. Data also showed a surge in average driving speeds as traffic declined last year.
Testing the systems
To conduct the study, IIHS partnered with Massachusetts Institute of Technology’s Advanced Vehicle Technology Consortium. Drivers in the study climbed behind the wheel of either a 2016 Land Rover Range Rover Evoque with ACC or a 2017 Volvo S90 equipped with ACC and Pilot Assist — a partial automation system that combines ACC with lane centering.
The data suggests drivers were 24% more likely to exceed the speed limit on limited-access highways when those systems were turned on. Not only were they more likely to speed, they drove faster when using the technology than when they drove without it. Overall, the test drivers sped 95% of the time using the technology while just 77% of the time when driving without it.
Whether driving manually or using ACC or Pilot Assist, speeders exceeded the limit by the largest margin in zones with a 55-mph limit. In these areas, speeders averaged about 8 mph over the limit, compared with 5 mph in 60 mph and 65 mph zones.
Automated cruise control also had the largest impact on how much they exceeded the limit in zones where it was 55 mph. In these slower zones, they averaged a little more than 1 mph higher over the limit when using ACC or Pilot Assist than they did driving manually.
Speed kills
Monfort notes that while 1 mph may not seem like much, its impact is more substantial than one may believe.
Leaving aside any other effect these features may have on crash risk, however, it means ACC and partial automation users are at about 10 percent higher risk of a fatal crash, according to a common formula for calculating probable crash outcomes. This study did not analyze real-world crashes.
“Driving faster is more dangerous,” Monfort said. “You can’t argue with physics.”
