Interstate 405

I-405, also known as The 405, is a major north-south auxiliary Interstate Highway in Southern California. It runs from Irvine in the south to Sylmar in the north and serves as a bypass for I-5, running along the southern and western parts of the Greater Los Angeles urban area. The freeway is the busiest and most congested in the United States, with an annual average daily traffic count of 374,000 between exits 21 and 22 in Seal Beach, making it the highest count in the nation. I-405 serves several major airports, including Los Angeles International Airport, Long Beach Airport, and Orange County's John Wayne Airport, and has played a crucial role in the development of dozens of cities and suburbs along its route.learn more on wikipedia