I’ve had the car for a few months and done plenty of hill starts. The car has always held its own and I’ve not had any bother......until today. I stopped at some traffic lights and the car was in drive but starting rolling backwards. I panicked and tapped the brake pedal took my foot off and it rolling backwards again. By now there’s a car coming so I put my foot on the brake, moved it into park and put the handbrake on. It had panicked me so I was nervous about moving off. I shifted it into drive, took the brake off and put my foot on the accelerator and off I went. Why did it happen?? It’s always just sat there on hills. It’s made me nervous to drive it again on a steep hill.

An automatic isn’t designed to just sit stationary on a hill. That’s why the car has a foot brake and a parking brake. When I stop my car for anything other than a momentary stop, I put the parking brake on. You can of course sit with your foot on the foot brake. But this irritates me. I hate looking at the brake lights of the car in front, so I don’t inflict it on others. The Edge is fitted with a hill start assist to prevent the car rolling backwards on a hill. This will only operate when the foot brake or parking brake are released. If you just leave the car in drive, hill start assist will not function and if the hill is steep enough, the car will creep backwards. 

Thank you, I’m new to autos. It is a super steep hill (I’m in Derbyshire), I drive it regularly but never had cause to have to stop before these temporary lights appeared. So I could keep it in drive and put the parking brake on at the same time. And foot on the brake pedal? Then when moving off release the parking brake, move foot to accelerator and it will hold briefly whilst I move off? 

1 hour ago, HugoB said:

it will hold briefly whilst I move off? 

It holds for up to 2.5 seconds, but the second you apply power to the wheels, it will release.

I live on the western edge of the peak district with some really steep hills and the hill hold has worked flawlessly. I personally don't use the park brake, I just hold it on the brake (Sorry @Edge of Reason!). I don't remember it ever rolling back in the 3 years I've had it. My biggest fear is the car in front rolling back and I can't roll back out of its way fast enough or at all! So I always leave bigger gaps to the car in front now .

10 hours ago, HugoB said:

Thank you, I’m new to autos. It is a super steep hill (I’m in Derbyshire), I drive it regularly but never had cause to have to stop before these temporary lights appeared. So I could keep it in drive and put the parking brake on at the same time. And foot on the brake pedal? Then when moving off release the parking brake, move foot to accelerator and it will hold briefly whilst I move off? 

Personally I put my parking brake on, then knock it into neutral, but you could hold it on the foot brake and leave it in drive.  If you leave it in drive with the parking brake on, the stop/start will not turn the engine off. As @simonb65 said you get 2.5 seconds to take up the drive with the accelerator when you either take your foot off the brake or when you put it in drive and take off the parking brake. That’s generally more than enough time to move off without rollback, even on the steepest hill. If your car doesn’t hold, then that’s a fault, but from your original post, you haven’t been using the brake at all. 

@simonb65 Each to their own, it just irritates me !! 😁