Cars go beep beep

Despite my best efforts, Nicholas has become car-obsessed. I am against the idea that the only things boys can be interested are modes of transport (look at all boys clothes/bedding/room design ideas etc. etc.) and have purposely avoided buying things with a transport theme, with exception of the traditional train set and a clicking car track.

This hasn't stopped Nicholas. About 95% of his 'conversations' (unless guided by me) include the words 'car' and 'beep beep' in close succession. A lot of them also include 'Halu' or Uncle Harry.

I don't really understand how, but he has developed a love of all things transport. He spots planes and helicopters, going so far as being unerringly accurate in telling them apart from sound alone. He points out all cars he sees and hears (as well as telling me that they go beep beep) and has started taking note of motorcycles.

Don't get me wrong, I don't have a problem with this.  I am against brainwashing boys into the belief that they *should* like cars etc. and am thus glad that he came to the 'boyish' interest in all loud, fast-moving objects entirely on his own. I just hope he doesn't expect me to play 'banging cars together' with him...