rogersleaf said:
Having driven commercial buses for over 30 years, I can’t believe this is DOT legal. Apply any type of engine brake or transmission retarder on a commercial bus will light the brake lights.
Where did you drive commercial buses? I have here in Colorado, both buses and some class A vehicles, and have never seen one that turns the brake lights on from engine braking. In fact, I've seen several that don't turn on the brake lights with the retarder, especially ones with Jake brake or exhaust brake type retarders. However, eddy brake retarders (either in the transmission or on the drive shaft) seem to always activate the brake lights, although I haven't heard of there being a law that the brake lights must come on with use of the retarder. But it would make since that eddy brake retarders activate the brake lights since they are one of the more powerful retarders.
As far as how that affects the brake lights on a downhill grade, we were taught to rely on engine braking mostly, with the help of the Jake brake or exhaust brake if so equipped (no brake lights), and then use the electric retarder and/or service brakes to slow the vehicle for a few seconds down by about 5mph every so often if need be (turning on the brake lights). The result at the brake lights is that for the most part they are off, but come one only once in a while when more braking is actually needed.
This helps to create less confusion since the commercial vehicles I drove didn't have extra deceleration lighting. The problem is that if the brakes did come on with engine braking or the retarder and the retarder were used during the whole descent, then the brake lights would be on continuously. If a herd of dear jumps out in front of the truck or come around a corner and there's a car stopped in the middle of the highway then to anyone behind the truck or bus they won't see any difference in lighting as it comes to a quick halt.
rogersleaf said:
The transit authority where I currently work installed deceleration lightning on every bus, works off a gyroscope switch and lights an extra set of amber lights when slowing.
That type of lighting would be ideal on any vehicle. BMW apparently did something similar to some of their cars. The ability to distinguish if the vehicle in front of you is calmly slowing down or if it's slamming on its brakes by means of lighting would be very helpful. But the problem is that most vehicles only show one level of brake lighting. And I don't believe there is a set deceleration level that all brake lights should come on that would work in any and every case. Making the only brake lights the car has come on at a certain deceleration threshold may make them come on too often or stay on when not necessary, like when going down a mountain pass, or may make them not come on at all when the should be on.
Maybe some day law makers will make automated brake lights that come on with well designed algorithms and perhaps extra deceleration lighting a must on all new vehicles. But I think they're going to make all cars have automatic braking first before they go that route.
rogersleaf said:
Not having a similar device on a LEAF is both stupid and dangerous.
That depends on the driver. I personally care about whether my brake lights come on or not. I don't care if that's going to upset my "one pedal" experience. If I feel the people behind me need to be warned that I'm slowing down, I apply pressure to the brake pedal, even if I don't need it for slowing down.
Granted, everything is slowly going away from letting the driver chose to letting the car do it automatically. And the B mode is one that seems to be easily used without consideration for those behind the car. But come on guys! Let's figure out how to drive safely in any vehicle first.
