After a heart-stopping moment when his young son went missing in a crowded museum, this Phoenix fireman credits ROAD iD with quickly reuniting them—now, it’s a daily essential for his entire family.

My Road iD was put to use when I was riding in the Big Dam Bridge 100. I was near the back of a pace line cruising along at 20+ mph. Suddenly the bike in front of me veered sharply, and I was looki...