Not to mention rubber tires.
Unless the cycle was dragging a chain or some other grounding device on the pavement there is no way he could have been charged. JMHO
With the amount of voltage and amperage you're talking about in a lightning strike, the rubber tires, etc., would be next to useless. That kind of juice would arc to the frame of the bike so fast it would make your...well, you get the picture. Also, if I recall correctly, most of the highway between Denver and Boulder is concrete instead of blacktop, so there are literally tons of iron rebar all in a nice grid 6 or 8 inches below the surface of the road.