If there was an all-star team of global positioning system (GPS) devices, reflector tacks would be in the starting lineup. They're the fingernail-size thumbtacks covered with reflective sticky-dots.

Tacks thrown in the road near the foot of the Jaizkibel climb sparked a number of sudden punctures on stage 2 of the Tour de France, with between 15 and 20 riders forced to stop to change wheels or ...