Roadblock

Summary
The Covenant employ "roadblocks" to block access to enemy troops and vehicles that might try to attack or bypass a fortified position. These roadblocks are small flat platforms that are placed on the ground, the top section is then pushed up on a hinge by an anti-gravity beam. The gravity beam can be disrupted by sustained weapons fire, or a small explosion, nullifying the roadblock's use by lowering the raised platform.

These can be seen around the level Outskirts.