Which factor prohibits large vans from being used to travel to Canada or Mexico?

The U.S. DOT Large Van Advisory is the key factor that prohibits large vans from being used to travel to Canada or Mexico. This advisory outlines specific operational and safety standards that must be adhered to when large vans are utilized for transport. It serves to ensure that vehicles meet certain safety requirements and are fit for the intended long-distance travel. The advisory acts as a regulation that restricts the use of these vehicles across international borders unless they comply with the stipulations set forth by the U.S. Department of Transportation.

The other options, while they may represent contributing factors to operational challenges, do not inherently serve as direct prohibitions akin to the advisory. For example, vehicle age restrictions might influence eligibility for use, but the advisory specifically addresses broader safety and operational issues which are crucial when traveling internationally. Local traffic regulations are context-dependent and vary by region, consequently not providing a uniform reason for prohibiting van usage across borders. Insurance coverage limitations may pose challenges, but these are often situational rather than outright prohibitions linked to government advisories. Thus, the U.S. DOT Large Van Advisory stands out as the primary factor restricting large van travel to Canada or Mexico.