Quickest and easiest way to do this is to use your car to block off a junction and wait for a queue of traffic to appear.
Then simply run along entering each car
and getting out straight away
. There's a high chance they will ring the police straight away and are right next to you when you get out of the car. Simply press
when prompted.
Pedestrians can ring the police too so do it near the sidewalk if you can.
This took be about 60 seconds to do.