Tokyo traffic can be so jammed that cops don't even need a vehicle of any sort in order to pull drivers over. This officer was working on foot a couple hundred meters from his police box. He just stepped out into the traffic jam, walked up to the truck, and told the driver to pull over to the curb.
I've seen Tokyo cops do this on foot, on bicycle, and on those little Super Cub motorcycles you sometimes see them on.
S-M-C Takumar 105/2.8