What it originally tried to inhibit was the depletion of oil; most EU members introduced it 30 or 40 years ago, during the oil-shock period. Nowadays gasoline taxation is just that, a tax, and a profitable one: it's grown to be one of the largest income items for most states.
(and if you think the various Middle-East wars were fought to keep oil prices under control, you're sorely mistaken; they were fought to maintain oil availability for corporations to exploit. Big difference.)
Could you elaborate?
I'm not saying this is a negative thing (in theory it's quite nice), but in practice it's just another way to help car-makers.
Most countries also dish out subsidies directly to struggling car-makers; companies like Renault and FIAT are seen as "national champions" and treated accordingly -- although this is now illegal under EU competition law, nobody complains because every manufacturer based in Europe will have enjoyed some "public love" at some point. After all, car manufacturing still employs, directly or indirectly, a lot of people.
Those benefits will go the way of the dodo once all the externalities will finally go into gasoline prices, at least in the US. Right now the EU I think does it better, it tries to inhibit owning a car by taxing gasoline prices extensively, while the US has chosen to start and fight apparently useless wars just to keep those gasoline prices under control.
And before I get accused of being a conspiracy freak just for stating the obvious, just remember that Japan's forays into SE Asia and Germany's desperate try to put its hands on Caspian Sea oil reserves during WW2 were made because of the exact same reasons: control of natural resources.