**Q: I have a car with automatic transmission. I have been told that I should leave my car in D' (drive) mode and step on the foot brake at traffic lights, rather than changing into P' (park). The reasoning is that frequent changes between P' and D' will wear out the transmission faster.
Others have said opposite - that leaving the gearstick in D' and stepping on the foot brake will cause it to use more petrol (because the car is trying to move against the brake), so I should change into P'.
Who is right?
A: If you are just stopping for a few seconds at traffic lights, say, there's no need to select P' (park) you can simply hold the car on the footbrake.
The torque converter inside the automatic gearbox will absorb most of the energy, so little or no wear is taking place.
Fuel economy shouldn't be affected, either. Unless you press the accelerator while holding the car on the brakes (not advisable!), the amount of petrol or diesel pumped into the engine shouldn't increase.
Moving the gearstick between park' and drive' will actually cause more wear than simply staying in drive'.
Beware, though, when the gear lever is in drive' the only thing stopping you moving forward is the footbrake.
So, if your concentration is needed anywhere other than the road or if you are stopping for more than a few seconds, we'd suggest selecting park' and applying the handbrake