Cart
From Halopedia, the Halo wiki
The cart is a vehicle that can be driven in Halo Reach. It can be found during the second level, early on. It is located head straight past the first right turn, by the forklift.
This vehicle can be useful as a mobile sniping platform against the Elites nearby, but after that, it cannot be taken to the next area.
Description
The Cart looks like a luggage transport at an airport, having a yellow color and being attached to some other, non-drivable carts.
It is mainly flat, with a small railing on top.
Tactics
A player could use it in some ways, but it is mainly there for fun.
One idea is to have two people, with one player driving, and the other picking off enemies with the DMR.
Another tactic is to use it as a "mobile bomb." Have someone drive it into a group of enemies, then a second person throw a grenade or shoot it. This can be difficult on higher difficulties though.