Cadillac’s Super Cruise was rated at the top of Consumer Reports’ (CR) first-ever ranking of partially automated driving systems. When the driving convenience features offered in these systems are engaged, they use cameras, radar, other sensors, and sometimes mapping data to try to keep a car centered in a lane and control speed to keep the car a set distance in traffic from vehicles in front.

According to CR, Super Cruise was top-rated because the testing showed it does the best job of balancing high-tech capabilities and ensuring that the car is operated safely and the driver is paying attention. In CR’s rankings, Tesla’s Autopilot came in second, followed by Nissan/Infiniti’s ProPilot Assist, and then Volvo’s Pilot Assist system.

Autopilot scored highly for its capabilities and ease of use, while Nissan’s system was better at keeping drivers engaged. Volvo scored comparatively lower. 

The four systems were judged not only on how well the technology works, but also on how well it monitors driver engagement and reacts if drivers do not respond to warnings. CR found the latter items to be especially critical because research shows that when these systems are engaged, drivers may pay less attention and rely too much on the automated steering and speed control.

CR is also monitoring how vehicle manufacturers market the systems, and whether they send mixed messages and suggest that the systems have self-driving, or autonomous, capabilities.

The four systems were chosen for testing because they are among the most capable and well-known on the market. In addition, although other automakers, such as Honda and Toyota, offer similar features, they aren’t marketing their automation capabilities the same way.

The top-rated Super Cruise by Cadillac tries to ensure that drivers stay focused by training a small camera on their eyes that assesses whether they’re watching the road. If the system determines that a driver isn’t paying enough attention, the driver gets red warning lights on the steering wheel, audible alerts, and/or a vibrating seat before the system starts to slow the car down.

These automated systems are not limited to the vehicles tested by CR, and mainstream vehicles are catching up with the technology. Kelly Funkhouser, CR’s Program Manager for vehicle usability and automation, notes that the more capable automation is, the more often drivers tune out. As these systems become common, more must be done to make sure drivers stay aware and engaged.

“Driver monitoring becomes necessary when motorists can push a button and hand over control of the vehicle,” she said. “Manufacturers have the ability to monitor drivers and use that information to respond when attention fades, rather than relying on ineffective warnings.” 

Jake Fisher, Director of auto testing at Consumer Reports, said that given the current state of the technology, drivers must remain constantly engaged. “If you have one of these systems, or are interested in buying a car with one, you need to understand the reality: You are always responsible for driving the vehicle, no matter what the car is doing to help you out.”