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What’s up with electronic parking brakes?

In most modern cars, the cable-operated handbrake (or foot pedal) has been replaced by an electronic push/pull button commonly named ‘P’.

So, does P have the same skill set as the old-school handbrake?

Short answer – sort of. Firstly, the traditional cable-operated parking brakes did – and continue to do – what they were designed for, although they’re a little more basic than their electronic equivalent. Pull the lever up – brake on. Release the lever – brake off. That’s about it.

Handbrake
Cable-operated handbrake. Image: RAA

On the other hand, electronic brakes have a bigger bag of tricks.

In many modern vehicles, the park brake will automatically be applied when the car’s engine is switched off. The brake might also engage if a seatbelt is unbuckled, a door is opened, or the gear lever is moved to the park position. In some cars, the brake will disengage automatically when you touch the accelerator to drive off.

In some manual cars, the electronic park brake will disengage when the clutch starts to bite. Older cars require the brake button to be manually operated.

Hold on

Those of us who drive a manual are familiar with the delicate hill-start dance involving accelerator, clutch and handbrake. Get it wrong and endure the embarrassment of a mid-traffic stall. Get it really wrong and you roll into the car behind.

Many newer vehicles have a feature called hill-start assist. The system will hold the brakes on for a couple of seconds while the driver’s foot moves from the brake pedal to the accelerator. This can relieve the panic usually experienced when the car behind pulls up within a whisker of your rear bumper.

Hill-start assist can take a little while to get used to, and cars differ in how much pressure is required on the accelerator to disengage the brakes. Keep in mind, the brakes will release after the allotted time.

Another system found in modern cars is brake hold. Popular on South Road during peak hour, it allows the driver to remove their foot from the brake pedal while sitting in traffic. The brakes will disengage once the accelerator is pressed and re-engage when the car comes to a complete stop again.

Park brake with brake hold. Image: RAA
Brake hold is ‘Auto hold’ in this vehicle. In some vehicles it’s an ‘A’ in a circle. Image: RAA

It’s an emergency

Whether cable-operated or electronic, the parking brake isn’t really designed for emergency stopping. But if the driver passes out at the wheel, it may be the passenger’s only chance to bring the car to a halt quickly.

This is where a major difference between the two systems will be revealed. When an electronic park brake is applied suddenly, the anti-lock braking system (ABS) kicks in to help bring the car to a controlled stop.

If you apply a traditional handbrake suddenly, the rear wheels will quite likely lock up, and where you finally stop is in the lap of the gods.

Each type of vehicle brand and model is different, so check your owner’s manual to find out how clever your car’s brakes are.