Canonically, this is the lightweight model meant for flatter ground, roads, and the insides of spaceship corridors, and it was deployed to a colony with paved roads and indoor corridors, so it had its adjustable suspension set to minimum ground clearance for better handling. Obviously, this was retrospective to explain away the exact point you're raising after they'd already made the prop and possibly released the film, but being a sci-fi vehicle, adjustable suspension, something that's available in cars you can buy today, would be something safe to assume it must have just from watching the film and noticing the lack of ground clearance.

It's obviously for a perfect undisturbed urban street with aliens on it.