Cycling's keirin is known as NASCAR on two wheels, and the pace car's a guy on a scooter
A green-and-white scooter buzzes along, its electric motor humming as it circles the polished wooden track at the Olympic velodrome.
Ivo Siebert keeps to a modest pace with a pack of elite cyclists following close behind. He can sense their impatience to burst past, can feel the rumble of their...