System attributes that influence reported improvement in drivers' experiences with adaptive cruise control and active lane keeping after daily use in five production vehicles

December 2018

Driving automation technology only will deliver safety benefits if drivers use it, but little is known about experiences with these technologies on actual roads. Fifty-one Insurance Institute for Highway Safety employees used an Audi A4 or Q7, Honda Civic, Infiniti QX60, or Toyota Prius as a personal vehicle for up to several weeks and completed surveys about their experiences. Each vehicle was equipped with adaptive cruise control (ACC), and the Audis and Honda had active lane keeping (ALK). Mixed-effects regression analysis found drivers agreed ACC improved the driving experience more than ALK on average, but this was not true for all vehicles. On average, drivers agreed that the Honda’s ALK improved the driving experience more than its ACC, but the opposite was observed for the Q7. Drivers were most comfortable using automation on interstates with free-flowing traffic, and least comfortable using ACC on low-speed local roads and in stop-and-go traffic and ALK on curvy roads; manufacturer guidance in the owner’s manual about use in these situations was inconsistent. Increased agreement that the technology made smooth and gradual changes to vehicle control significantly predicted increased agreement that ACC and ALK improved the driving experience. Based on these results, designers should strive to implement driving automation technology that drivers feel makes smooth and gentle changes to steering or speed because these attributes improve drivers’ perceptions of the technology. Models of automation acceptance suggest that more positive perceptions of driving automation technology would encourage broader use and increase the technology’s opportunity to provide safety benefits.