Perhaps the reason that I find cars so difficult to draw is that they’re almost human. Headlights can be like eyes, so, as when drawing a portrait of a human, if you don’t get the shapes or proportions right, you can lose the likeness. If I drew cars often enough, I might get to the stage where I could take liberties and come up with a caricature.
The first car got driven off just before I got a chance to add colour. As I added colour to the second, a Fiat Punto, I realised that because a car is so shiny it mirrors its environment with a reflection of the sky highlighting the roof and the reflection of the tarmac adding to the shadows below.