THE FIRST TIME I rode a motorcycle on a street was when I steered a 650-pound Harley-Davidson into traffic in Las Vegas. On that August morning, with sweat beading under my brand new goggles, my worst fear was stalling the engine or teetering sideways in front of the bikers who had just filled out my rental paperwork. Any concerns about tractor trailers, hairpin turns and other hazards took a back seat to the potential for injured pride.

I slowly rolled back the throttle with my right hand, while carefully releasing my death...