The normal terminology for the sides of a car are 'nearside' and 'offside', with the nearside being where the kerb is, offside being where other cars would be.

The normal terminology for the sides of a car are 'nearside' and 'offside', with the nearside being where the kerb is, offside being where other cars would be. So I would suppose 'inside' and 'outside' were also considered relative to the kerb.