Originally Posted by I-Like-To-Bike

Your estimates are neglecting consideration that not all miles are the same in risk to the driver and rider. Cars can be driven on just about any street or road without much driver concern/anxiety about increased personal risk from the specific traffic density or velocity, or the width of the road, or the presence of road shoulders. For the cyclist, those riskier traffic scenarios may rule out riding the riskier miles even if the distance and perhaps even time is identical to driving those miles. The traffic stats you cite presumably reflect cyclists' collective decisions to avoid cycling at all on the cycling unfriendly miles, even for relatively short distances.