dune buggy

from The American Heritage® Dictionary of the English Language, 4th Edition

• n. A recreational vehicle having oversize tires designed for use on sand dunes or beaches, especially a light vehicle with a modified engine mounted on an open chassis. Also called beach buggy.

from Wiktionary, Creative Commons Attribution/Share-Alike License

• n. A recreational vehicle with large tyres / tires, designed for use on beaches and sand dunes

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• n. a recreational vehicle with large tires used on beaches or sand dunes