Ambient noise includes all sounds present in an environ-. ment. The ambient noise level may be measured at any mo-. ment, but it will vary widely with time, e.g., with the coming. and going of trucks and aircraft. Traffic noise is higher at. noon than at midnight and higher still during the morning. and evening rush hours.
(According to the most recent U.S. numbered highway log, published in 1989 by the American Association of State Highway and Transportation Officials, the route is 3,249 miles long). In 1963, therefore, U.S. 20 became the longest road in the country. U.S. 20 is 3,365 miles long according to the 1989 log. The route begins in Boston at a junction with Massachusetts Route 2 and ends in Newport, Oregon, at a junction with U.S. 101.
7 of the Longest U.S. Interstates. Historic, iconic, impossibly long. Seattle to Boston. San Francisco to Teaneck, New Jersey. Even Miami to Sault Ste. Marie, Michigan. The routes U.S.'s longest interstates cover a variety of our nation's landscape, some deluged by major metropolis traffic, others linking oceans to the heartland. But the plan started by President Dwight Eisenhower in 1956 to create a 41,000-mile national system of interstate highways has continued to this day.