Expert witnesses argued that continuing the ban actually forced motorcyclists with passengers to use less safe routes of travel. According to a study conducted by Dynamic Research, Inc. (DRI), a safety research firm retained by Harley-Davidson, riding on motorways in Japan is 13 times safer than riding on ordinary roads and city streets, which have intersections,opposing traffic flows, poor visibility and mixed vehicle usage. The study also showed that tandem riding actually increases a motorcycle's stability at motorway speeds, and that motorcyclists who carry a passenger tend to drive more carefully than single riders.

The U.S. Department of Commerce and Harley-Davidson believe that Japan's ban on tandem riding hinders the sale of large displacement motorcycles there. Japan is the only country in the world to prohibit motorcycles carrying passengers from using its motorways due to unspecified safety concerns.

The OTO is expected to make a recommendation later this year.