On the road to fully autonomous driving, there are a few milestones that give us some hope. Cars like the Volvo S90 that can adjust speed for the car in front of you on the highway and a Tesla Model S that can go hands-free for short periods have already set the bar.
Another milestone? A feature on the 2018 Mercedes Benz E400 called Active Speed Limit Assist.
It’s not brand new, and you can find it on other Mercedes models like the S-Class and several BMW models, but it’s a sign of things to come – adaptive intelligence, machine learning, image recognition, and real-time mapping on major highways.
As you drive, the E400 will adjust the speed you are driving to match the post limit. (You have to enable the feature in the main display; to activate, just use cruise control.)
It’s an exciting innovation for a few reasons. One is that you don’t have to think about the speed limit (say what you will at this point about going 5 mph over the limit, which many drivers feel is an acceptable risk).
You can pay attention to other things, like the sports-car on your bumper. Of course, you should always be aware of your speed.
More than anything, it shows how cars are becoming more aware of the roadway, the posted limits, and eventually could sense imminent dangers long before you see them yourself.
In testing it, there’s a feeling that an AI has taken over, one that adjusts automatically. On a four-lane highway, the E400 surged gently forward at times before we even realized the limit had changed.
This can help in situations where you are driving slowly and don’t realize why everyone is looking at you. In one case, a jump from an area with stoplights with a speed limit of only 55 mph suddenly changed over to 70 mph.
Mercedes doesn’t do the abrupt speed change common on other vehicles that finally have adaptive cruise control, like the 2018 Toyota Prius Prime. Instead, it’s gradual.
During a longer test outside of a major city, there were times when we forgot the E400 was even changing speeds. It’s easy to see how future cars will also read conditions like construction zones, icy pavement, an accident, and other problems reported either to traffic centers or that the car can identify.
Still, Active Speed Limit Assist isn’t perfect. It worked for us only at normal highways speeds; in a traffic jam on a lonely country road with poor lane markings, it wasn’t available.
Another specification to consider? The optional Premium 3 package adds $10,200 (about £7,320 / AU$13,080) to the $58,900 (about £42,274 / AU$75,538) base price. You’re driving forward into the future, but not at Toyota Prius prices.