Routes: how to get mycontroller/id function same as mycontroller/action/id

[eluser]heha[/eluser]
I'm facing the same problem wtih you, dreamynsx. But in Zaatar's reply has already showed the way to complete that.

Try:
$route['(cars/[a-z]+)'] = "cars/index/$1";
(Close route with bracket.)
That's it.

Anyway I still don't know why this work. Don't know very much with regular expression.