Generally, it’s unnecessary to signal when passing parked cars. Excessive signalling in this situation can confuse other drivers as they may think you’re turning right. However, there are situations where a signal will be of benefit and eliminate confusion. For example, if you’re on a narrow road and have to stop to give way, your road position could look like a parked car. A signal to the right on this occasion will inform the driver behind that your intention is to continue and pass any parked cars once your way is clear. It’s not always parked cars of course. Any object on your side of the road that requires you to give way to oncoming vehicles may require a signal, especially if there’s a vehicle behind you which you think may not be able to see the hazard. This could be small road-works or debris, for example, and a signal will make your intentions clear.