Thanks to Bruce for the tip to this
story at NPR.
I've spent a lot of time in Mexico, and this is not like any other event I've ever seen. Not only does it start exactly on time, the organizers are sticklers for safety and follow every rule of the road.
They have monitors all along the route. They stop at every red light, and everyone has to wear a helmet.
If you've ever been to Tijuana, and rode a taxi blazing down a sidewalk because the streets were "too crowded", you know what a challenge this daily ride must be!