My first car was a Citroen GS in the early 80s. Bad choice if you want to repair it yourself. This had the hydraulic system. When that failed, so I could not raise the suspension, take off the brakes, or move the clutch. Probably the same was true of the DS, which came out in the 50s.
This all sounds like the protests against the safety of the Airbus ‘fly by wire’ systems as if the pilot of a 747 actually waggled the wings by moving the stick with his muscle. Yes, you can move the wheel if power steering fails (I have had that happen too) but it is a bit of shock when it does.
There’s no difference between an “emergency” brake and “parking” brake - they are the exact same thing: an auxiliary brake mechanism. Only the name is different. The function is identical: a mechanism that engages some sort of auxiliary (usually mechanical vs. hydraulic) braking mechanism. It might engage the existing brake pads, or it might engage a smaller brake.
An electrical parking brake generally works by engaging a screw that engages/disengages a braking mechanism. A mechanical one is just a ratchet that pulls a long cable that does the same.
An electrical parking brake should still engage when the car is running, you just have to hold down the button for a few seconds to tell it “yes, I’m sure I want to do this”. Not so great for drifting, but fine if you really need it.
Fine, let’s not get hung up on nomenclature, but can we agree that their utility in emergency scenarios are not the same? Using a hand brake (which is what I’ll call the lever-operated brake common on older sedans) provides instantaneous braking if a situation called for it, and the amount of braking force can be controlled if you hold down the release button with your thumb so that it doesn’t lock up. An electric button that you have to hold down for a few seconds, followed by a binary, full engagement of the brake, is not necessarily going to work out well in certain situations. Not every emergency scenario has several seconds to spare.
But more relevant to the subject of this discussion thread: electric brakes require electric power, so there’s more failure modes. I absolutely don’t have faith that the one in a Tesla would function if the computer was restarting. As you pointed out it’s not a direct connection to the electric actuator on the brake- the car’s computer has to see it pressed for several seconds before telling the brake to engage.
Meh, I feel as if you’re greatly overestimating the effectiveness of a parking brake in an emergency scenario and the ability for someone who doesn’t know any better to be able to use it properly in an emergency and not get themselves in even worse trouble.
Had a similar issue in a rented Tesla Model X. Accelerator continued to work and autopilot was engaged and still driving, but when the passenger tried to bring up the owner’s manual, the front panel (including speedometer) and center display both went black at around 80mph on the highway.
Climate control shut off, music stopped, and then everything rebooted about 1 minute later.
Was able to reproduce it and get it on video, although the speedometer didn’t crash the second time around.
Was quite scary, but since accelerator, brake, and steering kept working, it was manageable.
In a lot of jurisdictions I’ve worked in, there are laws about emergency-stop buttons that prohibit any programable logic in the circuit. You’re allowed wires, switches, and relays, and that’s pretty much all.
