I'll play devils advocate for a bit.
If car tires were superior over motorcycle tires why wouldn't a motorcycle manufacturer jump on the occasion and outfit their bikes with CTs from the factory? If manufacturer 'A' advertised their bikes were outfitted with car tires which offer superior handling and milage with the same or lower price point to you the consumer, wouldn't that be a huge marketing advantage for them over other bike manufacturers? Similarly, if Goodyear came out with a guaranteed million mile tire that cost less or the same than a top of the line Michelin, wouldn't you buy it for your Ford or Chevy or Honda? If running car tires on a motorcycle was simply better why has no one jumped on it? Why are insurance companies who have to payout loss of property and injury claims not saying CTs are safer? Are companies like Metzler and Shinko making so much money selling bike tires they can pay Honda, Suzuki, HD, Progressive, Allstate and everyone else to keep their mouths shut year after year after year? Perhaps the answer is so obvious studies don't have to be done.