“Leave the driving to us,” the ads for Greyhound used to say. While taking the bus is about as far as one can get from traveling via Mercedes-Benz S-class, that tagline also is appropriate for the latest version of the grandiose big Benz. For 2018, the S-class sees a mid-cycle update that brings powertrain changes, interior and exterior design tweaks, and, most significantly, enhanced semi-autonomous driving functions.
In the new 2018 S-class, the cruise control automatically adjusts its speed for curves, intersections, changes in the speed limit, and toll plazas. (Its knowledge of the terrain is based on GPS data.) This goes a step beyond the functionality previously offered in the mid-size E-class. The net effect is that one can use cruise control—and its attendant steering-assist function—much more often on secondary roads and not just on highways.
This could be the biggest development in cruise control since adaptive cruise allowed drivers to use the feature in heavy traffic, provided that drivers get comfortable with it. It is a little harder to trust than simple adaptive cruise control. With the car in its default Comfort driving mode, the cruise control will slow considerably for curves—more so than you might on your own—before quickly accelerating back to the set speed. In Sport or Sport+, however, it doesn’t slow as much and carries more momentum through corners.
That aspect works fine, but what’s somewhat disconcerting is learning to trust the car to slow on its own when approaching intersections, because the driver must be ready to brake for oncoming traffic at a yield or to brake for a stop at a stop sign. If there’s no oncoming traffic at a yield and no braking is required, the driver can stay off the brakes and let the car do it all; if one does have to brake at a yield or for a stop, the driver afterward needs to hit the resume button to reactivate cruise control. (The resume and other cruise-control switches have moved to the left spoke of the steering wheel; M-B’s stalk-mounted controls are no more.) In addition to slowing for curves or intersections on the current road, if the driver indicates a turn onto a side street or into a parking lot, the car again will automatically slow for it.
Another major enhancement over last year’s S-class is that the semi-autonomous steering now can perform a lane change. The driver activates the turn signal, and the steering assist will make the lane change, provided the adjacent lane is clear. If not, the car will cancel the turn signal and wait to switch lanes. When it’s clear (within 10 seconds or so), the system will automatically reactivate the turn signal and steer into the adjacent lane; the instrument cluster indicates what’s happening. Autonomous lane changing works only on multilane roads; it will not execute a pass on a two-lane road.