To ask a really stupid question about driving

[uhhuhh]

I've been driving for years so I should know this, but I don't. I'm too embarrassed to ask anyone in real life. When you're driving do you always need to be pressing on the accelerator? I drive a manual & when I am going downhill I don't press the accelerator at all, the car sort of rolls down. If I am on a flat straight road I press my foot down a bit but not much. Do I need to do that or will the car move by itself provided it's in the right gear?

You don't need to always press on the accelerator. I think you worked it out already!

No. You don't.

I normally have my foot on the brake when going downhill.

You don’t have to always push the accelerator if you have enough perpetual motion to move, however you should always be in gear (when going downhill for example) otherwise it’s ‘coasting’ and you don’t have so much control of your car.

Bertie yep always got a foot on the brake downhill. Don't worry I have got my head round braking! It's just accelerating I am not sure about

Well yes, you do need to press the accelerator as if you don't press it at all then the car will slow down and stop. When going downhill, gravity is assisting you so you can roll without using the accelerator.

Thanks for the replies. And yes always in gear, but good to know about the accelerator. Wonder if this could reduce my fuel costs?

You don't need to keep your foot on the brake going downhill. Put the car in a low gear and brake before corners if needed.

always got a foot on the brake downhill. Don't worry I have got my head round braking

Don’t be so sure about that! You don’t always need your foot on the brake going down hill, often just lifting off the throttle will give you sufficient engine braking. Riding the brakes all the way down hill is a good way to generate brake fade. On the level you will of course need some throttle to maintain a steady speed. That’s kind of driving 101.

Don't ride your brakes downhill. You'll wear the pads/fade the brakes and you should be using the engine to apply the reactive force. I'm not saying don't brake, just don't sit on them.

Well yes, you do need to press the accelerator as if you don't press it at all then the car will slow down and stop

This, on a flat straight road.

Obviously going down hill it would move on its own regardless of acceleration.

You should be in a low gear going downhill, not using your brakes!

I think of it like the pedals on a bicycle. If you pedal more you cycle faster. If you stop pedalling the bike will cruise along and slow down gradually, eventually coming to a stop. Same with the accelerator.

What do you do when you're approaching a junction, OP? Surely you decelerate on the approach by taking your foot off the gas? So you must already do this, surely?

Questions like this really make us women look so dumb...

Maybe the OP is a man!

If momentum will maintain the speed I want without pressing the gas then I don't press it. I don't ride the brake downhill either. Just drop a gear or two and it controls my speed.

Also on long straight roads cruise control does wonders for fuel consumption.

Charley, that must be it!

Here's the simplified physics:

If forces are equal then an object will remain at its velocity (or at rest if at rest).

When you are going down hill you have the force of gravity encouraging you down, and friction and air resistance slowing you up. If these are equal you will carry on with constant speed.

On a steep slope you may even need to brake to stop yourself speeding up.

On a flat road the air resistance and friction act to slow you down, so the car needs some kind of forward force. This force is generated by burning fuel in the engine, and fuel gets sent to the engine by you pressing down the accelerator.

Well no, there are three pedals and you only press one at a time.

*Press either the break or the pedal at one time with one foot.

So there are two pedals for one foot.

You can't press the brake and accelerator at once though because you're supposed to use the same foot.

I might be wrong about using the brake to go downhill, I have not passed my test, I've had lots of lessons with an absolutely shite instructor, so it's very possible he just didn't actually bother to teach me how to handle hills properly at all.

So...do heavy things with wheels roll downhill?
Yes! Yes they do.

when I am going downhill I don't press the accelerator at all, the car sort of rolls down

Well, yes, it would do. If you put an object on wheels at the top of a slope, what do you think would happen?