From Halopedia, the Halo wiki
Universe and lore
The HuCiv HC1500 is the most comparable to the ONI Van in terms of performance, size, and other functionality, especially the variant in the Halo: Reach campaign which has a built in compartment in the rear.
The ONI Van is a slow moving, two seater. It has a horn and makes a beeping sound as it reverses.
List of appearances