The Quad completely misses its point of being a noob vehicle atm.

It's almost as fast or faster as any other vhc (except aircraft). It's very easy/cheap to get. It has lower reqs than any other vhc.
Those points alone make it the best choice of vehicle for even high level players and therefor the result is that almost none of the other vehicles are used.

But the main problem is, that it cannot be destroyed and can be respawned with no penalty. This allows a playstyle that doesnt fit the normal Neocron experience of a harsh world where you have to watch out for yourself and your belongings.
At almost every busy place around the wastlands a few quads are parked, and if you meet another runner they never care for their quad.

My suggestion would be to give the quad a requirement like dexlvl < 60.