Interstate 10 in California.
The History.
Originally overlaid over parts of US 60, 70, and 99, I-10 was one of the original Interstate routes with it's route planned as far back as 1955. The Federal Aid Highway Act of 1956 authorized the building of the Interstate system, and California was quick to adopt the new route numbers. Unlike it's older sibling, the US Highway System, all Interstates were to be limited-access, meaning the use of on and off ramps was required. There would be no stop lights along the route and no at-grade intersections, in turn making all Interstates freeways. This was perfect for California, which has been developing and upgrading it's highways to freeway standards since the 1940's.
Reverse of the US Highway System, the Interstate system numbers south to north, west to east. This means the lower numbers will be found in the southwest US and the highest numbers in the northeastern US. This was done to avoid numeral overlap in states that had US Highways. Since the Interstate system is to double as a high-speed route to transport military goods across the country, similar to Germany's Autobahn, the system's full name is actually the Dwight D. Eisenhower National System of Interstate and Defense Highways. Most numbered highways with a numeral devisable by 5 are considered the most important routes in the system. I-10 is the southern-most, east-west running route to have a number devisable by 5. Being a transcontinental route, it acts as a major artery for all the states it runs through and has as key role in both foreign and domestic trade.
In California, the road enters the state over the Colorado River from Arizona into Blythe. It runs through the Colorado Desert, part of the Sonoran Desert, in Riverside County, into the cities of Indio, Coachella, and Desert Hot Springs. Continuing west, the road reaches the Inland Empire and San Bernardino County becoming the San Bernardino Freeway. It runs through cities including San Bernardino and Ontario before reaching Los Angeles County, continuing through Pomona, Covina, and El Monte before reaching the East Los Angeles Interchange. The San Bernardino Freeway ends here, and I-10 continues south onto the Santa Ana Freeway (co-routed with I-5). It quickly jumps off the Santa Ana onto the Santa Monica Freeway, following that route all the way to Santa Monica where it ends one block east of the Pacific Ocean.
In California, the road enters the state over the Colorado River from Arizona into Blythe. It runs through the Colorado Desert, part of the Sonoran Desert, in Riverside County, into the cities of Indio, Coachella, and Desert Hot Springs. Continuing west, the road reaches the Inland Empire and San Bernardino County becoming the San Bernardino Freeway. It runs through cities including San Bernardino and Ontario before reaching Los Angeles County, continuing through Pomona, Covina, and El Monte before reaching the East Los Angeles Interchange. The San Bernardino Freeway ends here, and I-10 continues south onto the Santa Ana Freeway (co-routed with I-5). It quickly jumps off the Santa Ana onto the Santa Monica Freeway, following that route all the way to Santa Monica where it ends one block east of the Pacific Ocean.
When the route was first adopted, it was signed in California as early as 1958. It followed US 60 and 70 through the Colorado Desert on a route not built to Interstate standards. In Indio, it picked up US 99 as well, and continued west, reaching the San Bernardino Freeway. Until the Santa Monica Freeway was completed in early 1960's, I-10 ended at US 101 in East Los Angeles with US 60 and 70. US 99 continued north with I-5 on the Golden State Freeway through Hollywood and the San Fernando Valley. In 1964, California had a large route re-numbering, completely shaking up the state's highways and their numbers. Legislative Route Numbers (LRNs) were completely redone to use the primary number as the LRN. In the case of I-10, it became legislatively Route 10, I-5 became Route 5, etc. California also took this opportunity to limit the amount of overlapping route numbers that made travel sometimes cumbersome. The quad-plex of numbers that was I-10, US 60, US 70, and US 99 was whittled down to just I-10 and US 60 from Blythe to Banning in 1964, with US 60 being completely removed in 1972.
I-10 now occupies this route all to it's self, with the exception of the US 95 overlap from Blythe into Arizona, which only runs for a mile or two in California. US 70 was completely removed and US 60 and US 99 were both deleted and the parts that didn't overlap with an Interstate became part of their respective State Routes (SR 60 and SR 99). When the Interstate system was funded, California jumped in head first. There are only three US Highways in Southern California that weren't completely deleted: US 101, US 395, and US 95. US 95 is the only US Highway in California wasn't truncated during or after the Great Renumbering of 1964 (US 101 was truncated to I-5 in Los Angeles, originally it ran to the US-Mexico border, and US 395 was truncated to I-15 in Hesperia, originally running to US 101 in San Diego).
The Travel Logs.
Video Logs: