> In a modern (<10 year old) car I question the "pro driver" result. I've been looking for data on this, and haven't seen anything that says this is true, but h

> In a modern (<10 year old) car I question the "pro driver" result. I've been looking for data on this, and haven't seen anything that says this is true, but have seen the opposite. There is an old SAE paper published by Chrysler that I can't find at the moment. IIRC, it was published in 1968 or 1969, and evaluated their new all-wheel[1] ABS system (later to be sold on the 1969-1973 Imperial). The gist of it is that on most surfaces relevant passenger cars, ABS gives somewhat ~shorter~ [Edit: longer ] stopping distances but the difference is minimal compared to a trained professional driver, and both are significantly shorter than locking the wheels (what a non-pro is likely to do in a panic situation) On ice, locking the wheels produces stopping distances that are several times greater than threshold braking. Wet pavement (especially asphalt) is better for ABS, too, though not as extreme as ICE. Importantly, threshold braking also enables the driver to maintain directional control on all surfaces, especially when the left and right wheels have different amounts of traction. ABS enables the driver to concentrate on steering while the computer adjusts the brakes. However, on dry concrete, as well as gravel or snow, locking the wheels does produce somewhat shorter stopping distances. (Concrete tends to be aggressively textured, almost like sandpaper; gravel and snow can build up a "ramp" ahead of a locked wheel) The only problem with locking for emergency stops is that 1) you wear the tires down to the cords after about 10 such emergency stops from 60 mph on dry concrete; and 2) the vehicle tends to spin. If the driver should happen to back off the brake pressure while partially spun, the vehicle will depart the road before they can react... so if you're going to lock the wheels, you have to really commit to it. [1] Chrysler had 4-wheel ABS 10 years before Mercedes' "first car in the world with 4-wheel ABS", but Chrysler had computer logic to release brake pressure on both rear wheels if either one slipped (it had sensors in both rear wheels), which is how Mercedes was able to claim a "first" with their system that simply treated both rear wheels independently.