Police Bike

It's hard to beat the big Harley for urban patrol/traffic work. Big, loads of low end torque that a 4 cyl won't give and comfortable for an eight hour shift. Top speed means nothing and putting around at 40 MPH doing traffic control or escort service handling isn't an issue. Most big departments have their own maintenance facility's and are set up with the special tools to maintain a Hog so that also becomes an issue.
A few years ago I was in Newark and noticed a car stall in the middle of the intersection a motor cop came along, put the front fender of his Harley up against the rear bumper and, without any effort, pushed the dead car out of traffic let's see your Beemer or Yamaha do that and not sustain any damage..

OTOH these might work for high speed highway work, but most departments have a 'Do Not Pursue' policy.