I don't think the author's main conclusion follows logically from any of the supporting facts. At best, one could conclude that bikers run lights because other

I don't think the author's main conclusion follows logically from any of the supporting facts. At best, one could conclude that bikers run lights because other bikers do (which is stated about halfway through the article). In no way do any of those facts conclude that bikers run red lights for an adrenaline rush.