Cadillac’s Super Cruise remains the top-rated active driving assistance system, according to tests by Consumer Reports. Active driving assistance systems don’t help a car self-drive but help support the driver with features like lane keeping.

In 2018, Consumer Reports conducted the first ranking of driving assistance systems from Cadillac, Nissan, Tesla, and Volvo. 

For this year’s testing, Consumer Reports looked at 17 systems, including the original four. Each of the 17 driving assistance systems was rated by its performance in 36 tests, such as steering the car, controlling the speed, and keeping the driver safe. CR’s testers looked at how each of the 17 systems performed in five categories: capability and performance, keeping the driver engaged, ease of use, clear when safe to use, and unresponsive driver.

Cadillac’s Super Cruise keeps the top spot because it uses direct driver monitoring to warn drivers that appear to have stopped paying attention to the road, according to Consumer Reports. 

The Super Cruise system uses a small camera that faces the driver’s eyes to determine whether the driver is watching the road. If the system determines that the driver isn’t paying attention, it sends several warnings, including bright red lights on the upper rim of the steering wheel. If the driver doesn’t react to these warnings, the system will start to slow the car down on its own and eventually bring it to a stop. According to General Motors, the Super Cruise system will be available on 22 GM vehicles by 2023.

For lane keeping assist, Consumer Reports rated Tesla the best (7 out of 10). Systems from Audi, Cadillac, and Lincoln performed almost as well. A good system is classified as helping the driver keep the vehicle well within the lane boundaries. Buick and Mazda didn’t perform well. Those systems don’t consistently keep the vehicle between the lane lines; they assist the driver only when a lane departure occurs.

For ease of use, CR’s testers looked at how easy it was for drivers to interact with the systems and make adjustments to settings. Tesla performed the best with a 7 out of 10 with Porsche, Land Rover, and Volkswagen not far behind with 6 out of 10. 

“The best systems allow drivers to activate the steering and speed control independently so that drivers can decide exactly how much assistance they want to use, and only have a single lane keeping system that performs consistently,” said Kelly Funkhouser, CR’s head of connected and automated vehicle testing.

Consumer Reports also evaluated the systems in how they communicated in real time about when drivers should (and shouldn’t) be using the technology. Most systems restrict their use in less-than-ideal situations, according to Consumer Reports. Cadillac’s Super Cruise topped this category (8 out of 10) because it will warn drivers in advance when there is an upcoming lane merge or situation that might require more attention.

For the unresponsive driver category, Consumer Reports evaluated systems for their escalation process for warnings, steering control, and speed control. Most of the systems will send an alert if the car judges the driver to be inattentive for a period of time and then bring the vehicle to a stop with the hazard lights on. Cadillac topped this category with a 9 out of 10 and Nissan’s system took second place with a 7 out of 10.

“We’d like to see developers of these systems consider the additional step of steering the vehicle onto the shoulder of the road when a driver becomes unresponsive, and providing this feature even if the driver wasn’t using the system,” said Funkhouser.