Heavy Ramming Vehicles (abbreviated HRVs) are unmanned juggernaut-class vehicles that the police can request support from. They are of medium speed, and cannot be hijacked or damaged. However, there is a limit to the number of HRVs that can be used at any time, and all HRVs are limited in terms of fuel, and therefore, field presence.
If a Heavy Ramming Vehicle arrests a driver, the Cop gains 50 points under the "HRV Arrest" title.