Raining? Rely less on your driver-assist systems

A report recently released by AAA says that rain doesn’t just make roads harder for human drivers to navigate. It also can impair your car’s automated systems like emergency braking and lane-keeping assist.  

In closed-course testing that simulated rain on the windshield, automated emergency braking failed to keep the car from running into a stopped vehicle at 35 mph about one-third of the time. When it came to lane-keeping assist, the test car strayed out of its lane 69% of the time. (The cars did somewhat better at lower speeds. In emergency braking, for example, they crashed 17% of the time at 25 mph.)  

The upshot: Drivers need to stay fully engaged at all times – but especially in the rain, even when they have the benefit of driving a vehicle with assist technology. Also, it’s very important to keep windshields clean and replace wiper blades frequently, since sensors for these technologies often are located behind the windshield and can be obstructed by a less-than-clear view. We also urge you to fix any windshield dings or cracks promptly. 

To conduct the test, AAA set up a gizmo on several driver-assist equipped models to spray their windshields with enough water to simulate moderate to heavy rain. Then, they put them on a test track to measure the effectiveness of the driver-assist technologies in the less-than-optimal weather conditions they created. 

They also tested whether the presence of dirt or bugs on the windshield made a difference. It did, but only slightly compared to the simulated rain. 

Fortunately, no matter what kind of car you drive, there’s a lot you can do to make driving in the rain safer. They include: 

• Slowing down and increasing following distances 

• Replacing wiper blades annually; sooner if they’re streaking 

• Turning on headlights any time the windshield wipers are on 

• Making sure your tires have sufficient tread to effectively displace water on the roadway 

• Avoiding standing water 

• Turning off cruise control in rainy, icy or other unfavorable conditions. 

You can see our full list of rain-driving tips here.