During the driving test, the examiner will want to assess your ability to safely park up on the left and move off again. The examiner may ask that you park up on a flat, level surface, or on a slope so that you can demonstrate either a hill start, or a downhill start.
Unless you live in a particularly hilly area, then you can usually move off as normal, in Drive (D) and control the speed of your car via the brake pedal. However, if the downhill slope if quite steep and especially if it’s quite a long, steep slope, you’ll need to know a thing or two about how to safely control the vehicle’s speed when descending. You’ll need to know about:
- Brake fade
- Engine braking
- Manually selecting gears
In simple terms, brake fade can occur when your vehicle’s brakes overheat. Overheating can occur, for example when driving downhill when constantly using your car’s brakes for an extended period of time.
Friction causes the brakes to heat above their operating levels and when this happens, brake fade may occur. During instances of brake fade, you may find that the brakes become less responsive and have a reduced ability at slowing down the vehicle.
To help minimise the risk of brake fade occurring when driving downhill, we need to reduce our reliance on the vehicle’s brakes and to do this, we make use of engine braking. Engine braking is simply the term we use when we remove our foot from the accelerator pedal and the car slows down due to the friction and vacuum of the engine. See engine braking for a more detailed explanation.
Manually Selecting Gears
As drivers of automatic cars, many of us are not familiar with the manual gear change option that almost all modern automatics provide. One of the reasons why automatic cars have a manual option is for driving downhill.
When driving downhill, rather than allowing the car to automatically change up gear, if we keep the car manually locked in a lower gear, it’ll increase the effect of engine braking, which in turn reduces the risk of brake fade. If you’re not too sure about automatic cars and manual gears, see how to change gear in an automatic car.
Starting Off Downhill
When carrying out a downhill start in an automatic car, you can usually start off in Drive (D), just as you normally would. On steeper slopes however, start off in manual mode.
Automatic cars will always shift up a gear at the earliest opportunity as this will help to increase the car’s fuel economy. Because you’re going downhill, you’ll want to keep the car slow and also keep it in a low gear to help with engine braking. This is why you’ll want to move off downhill in manual mode.
If you need to increase a little speed, manually shift up into 2nd gear. 2nd gear is usually an appropriate gear for driving down a slope as it provides a good amount of engine braking while still keeping the car slow.
By using a low gear and therefore increasing the amount of engine braking, it means you should be able to feather the brakes on and off. This allows the brakes to cool, which will reduce the risk of brake fade.
Once you’ve reached the bottom of of the hill, you can shift your automatic from manual mode, back into auto mode (Drive). You do not need to stop the car when shifting between Drive (D) and manual mode.
Tips for Private Practice
If you’re giving a learner driver private practice, read up on our tips for teaching hills starts, downhill starts and driving downhill in an automatic car.