|Adeptus Arbites wrestle with rioting citizens.|
I suspect that if you had to specify a riot control vehicle for your local law enforcement outfit, the sort of thing that would spring to mind would be a wheeled APC, perhaps with a turret mounted watercannon. Possibly with a dozer blade for clearing out barricades and shunting aside burning wrecks.
Something like one of these:
A few years ago, I used my Adeptus Arbites in a couple of games. I didn't have anything suitable ready to go, so I picked up a marginally over-scaled but cheap toy police vehicle (with sound and light action). This vehicle has seen a fair bit of use in games which require swift deploying of Arbite troopers. It can even be operated by Jokaero. The flashing lights and nee-naw sounds are of course, a bonus.