That's just BS. Most of the braking happens on the front wheels, emergency or not. The rear wheels does fuck all for braking.
I never understood why the americans even call it an "emergency brake". That's what the normal brake is for, for stopping the car, emergency or not. The handbrake is a parking brake, for keeping the car stationary. Not for stopping it.
Because in ancient times, mainstream cars used drum brakes actuated by cables, even later than this 1935 video.
The cables would sometimes snap due to lack of maintenance, manufacturing defects, or most commonly road debris or operating conditions would break a cable or otherwise render it useless. At that point you have NO brake control with most designs. Your only remaining control channel to the brakes was the totally separate backup or '
emergency' brake control - which actually didn't have a ratcheting mechanism to begin with. Only after they gained a ratcheting mechanism to become dual purpose were they marketed as 'parking brakes'. Manufacturers continued to market them as 'emergency brakes' through the 1970s when product liability lawsuits began to force them to change the nomenclature.
Duesenberg debuted the world's first hydraulic service brakes in 1921 but it took a very long time to catch on by modern standards and right through WW2 the vehicle fleet was majority cable brakes. Most of Europe was, as well. The Austin 7 originally shipped with all four brakes controlled by a hand lever and the foot pedal only actuated the rear brakes - all through cables, to pick one example. However, as always, Europe was kinder to ground vehicles than the Americas are and Europeans had far fewer issues with snapped cables and related brake failures.
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In a lot of EPB systems, if you hold the switch up while the car is in motion it gradually applies the brake.
No, it *tries* to apply the brake. There have been a number of tests where they sometimes don't seem to have enough power to apply the brake in a dynamic situation. Hint: Don't try this with any of the recent Jag electronic parking brake systems.
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Serious question: What's the reason handbrakes are always on the rear axle of a car?
Not having to deal with a system that can pivot because of the steering?
They didn't use to be (see above) - today they're always on the rear because it is far easier and cheaper to engineer them back there (for reasons including the ones you posit) and (as others have noted) you can't lock the front wheels and thereby lose steering control, if you really are using them in an emergency.
However, some larger (but non-commercial) 4WD/RWD vehicles do not have wheel-mounted handbrakes. Instead they use a driveshaft or transmission brake as their even larger cousins do.
Disc versions exist as well.