While assistive driver technology continues to advance, lingering issues persist relating to traffic jam assistance, according to a new AAA study.

AAA Automotive Engineers evaluated five passenger vehicles with low-speed-capable Active Driving Assistance (ADA) systems in heavy traffic. The study compared hands-on and hands-off ADA performance. Data showed that drivers intervene every nine minutes in heavy traffic.

The most common events were cut-ins and poor lane centering.

“Even though ADA systems can help out in certain driving situations, they’re not a replacement for paying attention behind the wheel,” said Greg Brannon, director of automotive engineering research. “What we’ve found is that drivers really need to stay alert and cut down on distractions, especially when things get busy on the road.”

Notable events were recorded every 3.2 miles, which is approximately every 9.1 minutes on average. A “notable” event was defined as any situation in which the ADA system failed to handle the driving conditions adequately, as determined by the researcher driving the vehicle.

The most common incidents reported were inadequate responses to cut-ins, which required a researcher to intervene 90 percent of the time. Cut-ins are defined as instances when a vehicle enters the lane directly in front of the test vehicle.

The second most frequent issue was inadequate Lane Centering Assistance. Lane Centering is a driver assistance system that utilizes cameras and other sensors to keep a vehicle centered within its lane, providing steering assistance to prevent the vehicle from drifting.

Engineers reported a difference between hands-on and hands-off ADA systems.

Hands-on systems require the driver to keep their hands on the steering wheel while the ADA system is in use. The ADA system utilizes sensors such as cameras and radar to monitor the driving environment (road condition, lane lines, etc.).

Hands-off systems allow the driver to remove their hands from the steering wheel in most situations, but may require them to put their hands back on in certain conditions. These systems use similar sensors, but they also commonly rely on roads that are pre-mapped in the system.

The findings revealed that drivers of hands-on systems had to intervene due to driving events three times more frequently than those with hands-off ADA systems.

Though hands-free most of the time, drivers using hands-off systems were asked to re-engage by placing their hands back on the wheel approximately once every 5 miles or every 15.3 minutes, requiring continuous driver engagement.