Because the sections of historic Route 66 that are within urban Los Angeles (San Bernardino to Santa Monica) are still dedicated streets, they remain as the most used and heavily traveled Route 66 segments. However, because of the heavy traffic and later non-historic development along these sections, they are generally the least traveled by Route 66 enthusiasts. Modern guide books that describe how to follow historic Route 66 frequently suggest that when arriving at San Bernardino from the east, enthusiasts should enter Interstate 10 as a bypass for these segments exiting near Santa Monica to experience today's terminus.