Question: what is the standard lane width on an interstate highway?
Answer: In the United States, the Interstate Highway standards for the Interstate Highway System use a 12 ft (3.7 m) standard lane width, while narrower lanes are used on lower classification roads. In Europe, laws and road widths vary by country; the minimum widths of lanes are generally between 2.5 to 3.25 m (98 to 128 in).