Don’t Automatically Accept Automatic Emergency Braking as Foolproof

Some pre-autonomous driver-assistance systems don’t quite seem ready for primetime.

All the riders remounted and the race continued, according to Cyclingnews, but this wasn't the first report of a crash caused by AEB. A Mercedes-Benz race director's car automatically braked itself to a stop in a February 2018 Abu Dhabi event, and a rider suffered a concussion and whiplash as a result, Deadspin reported.

Days before the accident at the Belgian peloton, Consumer Reports announced it would no longer recommend any new car or truck that doesn't have standard AEB.

I fear we're having another airbag moment here, in which early examples of the technology are not ready for mainstream consumers. While the problem with early airbags was that they often inflated with too much force for smaller, shorter drivers and front passengers, the problem with AEB systems is that they have potentially unintended effects when everything else on the road does not have AEB. My personal experiences with AEB has convinced me that the technology will not be perfectly safe until the vast majority of motor vehicles have, at least, SAE Level 4 autonomy.

Most, if not all new vehicles equipped with AEB come with a defeat switch, and I expect that after those two accidents, bike race governing bodies will assure that lead-car drivers find where those switches are located. But as our Marc Noordeloos recently noted in his column, traction- and stability-control defeat switches are hard to find in many cars, especially for the type of driver who never even fiddles with their automatic-headlamp switches. If Consumer Reports really wants to make vehicles safer, the magazine ought to go after any manufacturer that buries defeat switches in a touchscreen menu. I'm going to make that part of my pre-drive regimen for every new model I get into.

I've had a few false-positives in various makes and models of the kind we just reported in our long-term Volvo. One sedan I was driving hastily activated its AEB while driving on a 35-mph stretch of Woodward Avenue when the car ahead quickly braked and was still four or five car-lengths ahead. And don't get me started on the warnings that light up a red BRAKE! graphic in the head-up display.

An eye-opener on the dangers of AEB came recently when I was driving back from our Automobile All-Stars competition in California. I was on my way to Los Angeles International Airport—another topic on which I shouldn't get started—in an Infiniti QX50, generally keeping up with traffic flowing at a moderate rate.

This is not to single out the Infiniti—its AEB is engineered just like any other automaker's, and they're all equally effective, which is the source of the technology's problem. I was zipping down the 5, as they like to call it in SoCal, and while I try to pass only in the passing lane, this is hard to do consistently in most of the U.S. and pretty much impossible in California. I can only avoid passing in the rightmost lane, where I'd risk cutting off a car trying to move over for an exit ramp. After all, there are plenty of drivers who insist on using the passing lane while making their phone calls and sending texts.

In this instance, I went to move from the left lane to the middle and back again in order to pass a rolling phone booth in my original lane and then another slower car in the middle lane. I would have about three car lengths of buffer ahead and behind as I moved back to the left. You can guess what happened.

This was not some banzai threading of a needle; as mentioned, there was plenty of space between the closer SUV in the left lane and the one further ahead in the middle lane. But when I got past the left-lane bandit and started to move left, the middle-lane vehicle apparently braked abruptly, triggering the SUV's AEB as I was getting back into the left lane.

My brake lights surely lit for a split-second as I changed lanes. I didn't see whether the left-lane occupant hit the brakes (he or she was probably too busy on a call to notice), and fortunately, my brakes quickly disengaged once my Infiniti's nose pointed to the left of the middle-lane vehicle. But if I were making it a closer cut between the two vehicles, I would have been rear-ended.

Consumer Reports may keep recommending only cars and trucks with such hand-holding technology. Here's my recommendation: If you're a driver who pays close attention to your surroundings and you drive defensively in any sort of traffic, read your owner's manual and figure out how to defeat the AEB.

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