Ever ponder how Interstate 8 came to be? It is more than just asphalt. It is a story of expansion, innovation, and even a little bit of controversy. This is the tale of M-8.
M-8 started modestly. Construction began in 1957 for a U.S. 80 freeway. It ran between U.S. 395 and Ward Road. By the early 1960s most of U.S. 80 freeway was done. It stretched east from U.S. 101 to El Cajon. In 1964, it was officially designated I-8.
Originally, the plan was for I-8 to end at Interstate 5. In 1971, the Ocean Beach Freeway was built. It was formerly California State Route 109. The route was then extended west. It went to the intersection of Nimitz Drive and Sunset Cliffs Boulevard.
Interstate 8 is quite the road. At one point, it was the lowest freeway in the country. It drops below sea level in the Imperial Valley near El Centro. The freeway also crosses several mountain passes. It runs between San Diego and Casa Grande, Arizona.
Leaving Ocean Beach, I-8 heads east. It cuts through the San Diego metro area. Beyond El Cajon and Alpine, the freeway winds. It goes through Cleveland National Forest and Laguna Mountain range. Then it angles southeast. I-8 passes through the In-ko-pah Gorge before Ocotillo. It continues through the desert hills and farmland in the Imperial Valley. The freeway enters Arizona at the Colorado River and Yuma. Then it advances east across more desert terrain. Finally, I-8 concludes at I-10. This is midway between Phoenix and Tucson.
Interstate 8 runs parallel to Old U.S. 80. This historic route is well-preserved. U.S. 80 follows Interstate 8 from San Diego to Gila Bend, Arizona. From there U.S. 80 turned north. It followed what is now Arizona Route 85 to Interstate 10 near Buckeye. You can still find stretches of Highway 80. They exist as frontage roads and county roads along the freeway corridor.
The easternmost stretch of I-8 is unique. It runs between Gila Bend and Casa Grande. This section was not a former U.S. route. Instead, the Interstate replaced former SR 84. A shorter section remains close to Casa Grande.
The Pine Valley Creek Bridge opened in 1975. This bridge carries the freeway over 200 feet above the valley floor. The bridge is a segmental balanced cantilever bridge.
Within Arizona, the earliest sections of I-8 were completed in 1959. These ran between Sentinel and Piedra. Another section ran from Gila Bend to SR 84. The Colorado River bridge west of Yuma opened in 1979. This was the last portion of I-8 to open overall.
Long pieces of Interstate 8 were open by 1963. They followed U.S. 80 through San Cristobal Valley. Other sections crossed Sentinel Plain and over SR 84. This was between the Sand Tank and Maricopa Mountains.
U.S. 80 was truncated in 1977. It ran from Yuma east to Benson. The remainder was dropped in 1989.
Today Interstate 8 remains a vital transportation route. It facilitates travel and commerce. The freeway connects communities and regions. I-8 stands as a testament to the progress and planning of the mid-20th century.
Interstate 8 has been widened in San Diego. This was done to address increasing congestion. A portion in Imperial County was rebuilt. This followed damage by the remnants of Hurricane Kathleen.