Wave the back of hand to mean 'thanks for allowing me to manoevre, oh venerable driver of motor vehicle who ISN'T trying to squeeze me up against a parked vehicle I'm trying to negotiate'.
Sort of like this, only you see the back of me. And I'm on a bike. And there, sadly, is a lack of flowers in the scene.
Wave the back of hand to mean 'thanks for allowing me to manoevre, oh venerable driver of motor vehicle who ISN'T trying to squeeze me up against a parked vehicle I'm trying to negotiate'.
Sort of like this, only you see the back of me. And I'm on a bike. And there, sadly, is a lack of flowers in the scene.