From Sonic Retro
|Games: Sonic Adventure, Sonic Generations|
It's a Kart Kiki using a police car instead of colour ones. It's parked until it spots a character, when they start driving around haphazardly in arcs with sirens flashing and blaring trying to hit its enemies. It appears in Speed Highway's, both for Sonic and Knuckles.
A Cop Speeder in Speed Highway.