California State Route 94

State Route 94 (SR 94) is a state highway in the U.S. state of California that is 63.324 miles (101.910 km) long. The western portion, known as the Martin Luther King Jr. Freeway, begins at Interstate 5 (I-5) in downtown San Diego and continues to the end of the freeway portion past SR 125 in Spring Valley. The non-freeway segment of SR 94 that continues east through the mountains to I-8 near Boulevard is known as Campo Road.

The Campo road served as a wagon road providing access to eastern San Diego County as well as Imperial County. The road was added to the state highway system in 1933, and signs for Route 94 were posted along local roads later that decade. Efforts to convert the western half of the route to a freeway got underway in the 1950s, and the freeway was complete by 1962 west of the road that became SR 125. Construction continued east to Avocado Road over the next few years. Various proposals for widening the highway have come from the California Department of Transportation (Caltrans), but local opposition resulted in the delay or cancellation of many of these proposals.

SR 94 is an east–west freeway that begins at the eastern end of the one-way couplet of F and G streets in southeast San Diego. The freeway continues through an interchange with I-5 just east of downtown. Following this, the route goes through the neighborhoods of Sherman Heights, Grant Hill, Stockton, and Mount Hope, where there is an interchange with SR 15. Shortly thereafter, SR 94 intersects I-805 in Chollas View before continuing east through Emerald Hills and Chollas Creek into the city of Lemon Grove. Passing by the Marketplace at the Grove shopping center, the freeway forms the boundary between Lemon Grove to the south and La Mesa to the north, up to the SR 125 interchange where SR 94 turns east. At this point, SR 94 leaves both cities and enters unincorporated Spring Valley and Casa de Oro.

The freeway becomes an undivided highway at Via Mercado in Rancho San Diego. SR 94 continues through Rancho San Diego by turning southeast at the Jamacha Road and Campo Road intersection, where SR 54 and CR S17 turn northeast. As Campo Road, SR 94 crosses the Sweetwater River before entering a less-developed area, winding through the communities of Jamul, Dulzura and intersecting the north end of SR 188 north of Tecate. After passing through the communities of Potrero, Campo, and the Campo Indian Reservation, SR 94 continues east onto old U.S. Route 80 (US 80) briefly before turning north on Ribbonwood Road west of Boulevard. The route ends by connecting to I-8 near Manzanita.

SR 94 is part of the California Freeway and Expressway System; west of SR 188, it is part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration. SR 94 is eligible for the State Scenic Highway System, but it is not officially designated as a scenic highway by the California Department of Transportation. In 2014, SR 94 had an annual average daily traffic (AADT) of 440 vehicles at Live Oak Springs Road, and 179,000 vehicles between I-805 and 47th Street, the latter of which was the highest AADT for the highway.

SR 94 was built along the routing of an old stagecoach road that was part of the primary road from San Diego to Yuma, Arizona. A trip to East County in the 19th century along the road would last two days. James Pascoe surveyed the route through Campo for the county in 1869 that was 25 miles (40 km) shorter than the existing route through Warner's Pass. The road was known for its curves, climbs, and boulders, making travel difficult. The first automobile went on the road in 1904. By 1913, an unpaved automobile road extended to Campo from San Diego, and work took place to improve the condition of the road in 1916. A year later, the road continued east to join with the state highway leading into Imperial County. In 1927, the Potrero bridge was replaced, after a storm washed it out. By 1928, the paving of the Campo road was about 43 percent complete. In February of the next year, the progress was at 74 percent; the total cost was $122,474 (about $4 million in 2024 dollars). The Sweetwater bridge was finished in March at a cost of $60,000 (about $1 million in 2024 dollars). The Campo road was the only road through the Peninsular Ranges to stay open for the entirety of the next winter; other roads were closed by snow, leading to increased traffic along this road. This was largely due to the lower elevation of the road, at only 4,000 feet (1,200 m).

In 1931, the County Board of Supervisors agreed to submit the Campo road for consideration as a secondary state highway. The state considered the inclusion of the Campo road into the system in 1932. The California State Legislature defined Route 200 in 1933 as a route from San Diego to west of Jacumba, going through the town of Campo. The San Diego Chamber of Commerce sent a representative to ask the state for funding for paving the Campo highway in 1935, and the road was paved that year. The Chamber also asked for the war department to declare the road a military highway to receive federal assistance for its improvement. Signs were posted for SR 94 in 1937, and by 1938, SR 94 was signed along Broadway and Lemon Grove Boulevard (later Federal Boulevard) before continuing east to Campo.

The next year, the California Highway Commission declined to have the Campo road improved. However, the Highway 94 association, as well as the Campo-Potrero and Highway 80 chambers of commerce raised concerns about the safety of the children going to school in the buses along the road. In 1952, the Southern California committee of the state Chamber of Commerce recommended to the California Highway Commission that Route 94 be widened to four lanes from the Wabash Freeway to Jamacha. In June 1953, the Commission approved an eight-lane freeway for Route 94 from Home Avenue in San Diego to Palm Avenue around La Mesa. The local Board of Education also gave their approval, which was required because the freeway would be built on land that was for a proposed school. But the next month, State Senator Fred Kraft criticized the proposal because he believed that it would be too expensive and would not reduce congestion in the long term. Approval extended to the junction with US 80 by October 1953; the part from 18th Street to Wabash Boulevard followed in November 1954. Later that year, a toll road that would have tunneled under the Laguna Mountains and bypassed Route 94 was proposed by the county Board of Supervisors. The state allocated $3.48 million (about $32 million in 2024 dollars) for making SR 94 a freeway from College Avenue to Campo Road in October 1954.