Interstate 15

California State Route 15Interstate 15

Interstate 15 is a major route that travels from the Southwest into the Intermountain West, connecting San Diego and Los Angeles to Las Vegas, St. George, Provo, Salt Lake City, Pocatello, Idaho Falls, Butte, and Great Falls. Interstate 15 replaced Former U.S. 91 almost in its entirety, although a short stretch of U.S. 91 remains in eastern Idaho and northern Utah.

Tolled Express Lanes accompany Interstate 15 north from the merge with SR 163 by MCAS Miramar to SR 78 at San Marcos and Escondido. The 20 mile system is free of charge for carpools, motorcycles, public transit vehicles and permitted clean air vehicles. Single occupant vehicles can use the Express Lanes for electronically collected tolls with a FasTrak transponder. Toll rates vary depending upon traffic flow.

Business Loops

There are five business routes for Interstate 15 in California:

I-15 Express Lanes

Interstate 15 has experienced the most traffic growth of any freeway in San Diego County. Fast-paced growth and a North San Diego County housing boom fueled traffic count increases along this highway, causing many to reconsider purchasing a home along the Interstate 15 corridor. Explosive development planned in 1998 included 12,800 houses planned in the Interstate 15 corridor, including Black Mountain Ranch (5,400), Torrey Highlands Ranch (2,693), and Pacific Highlands Ranch (4,974). Black Mountain Ranch made the news during the Fall 1998 campaign. Two local propositions, K and M, were approved by the electorate. These propositions opened parts of the City of San Diego's future urbanizing areas for development. One of the tenets of this agreement included Black Mountain Ranch paying for highway improvements, including along I-15 and California 56. With several hundred additional homes planned in Spring 2001, the Rancho Encantada development further advanced discussion of the impact of new housing against the existing highway infrastructure.

In 1988, Interstate 15 saw only about 196,000 cars per day. Counts over the intervening years rose to 281,000 cars per day, with the busiest section located between California 163 and Miramar Way. Analyst projections in the early 2000s estimated that I-15 will carry upwards of 330,000 vehicles, a 17% increase. Much of this traffic was due to new housing developments and the lack of major surface arterials that carry north-south traffic.

The need to improve Interstate 15 through this corridor did not go unnoticed at the state level. Governor Gray Davis' traffic relief plan, released May 3, 2001, allocated $5.5 million to a high-tech managed lanes concept along Interstate 15 between California 163 and California 78. This initial money funded a study to plan out the managed lanes concept. The total project cost was estimated to be around $535 million in May 2001. The high-tech component included sensors embedded in the concrete to make adjustments to the roadway to facilitate traffic flow.

Short-term solutions to this problem included adding more "auxiliary" lanes to Interstate 15. In some cases, this included restriping shoulders and narrowing lane widths to accommodate more freeway lanes. The auxiliary lanes enhanced traffic flow between freeway entrances and exits, while restriping allowed more lanes to fit in a narrow area, such as across the Lake Hodges bridge.

Some planners pitched the idea of creating a "zipper" system for Interstate 15. Under this plan, the freeway would be widened for southbound traffic in the morning and for northbound traffic in the evening. The three to four center lanes would be adjusted to accommodate traffic flow with a special truck that can move median barriers. Movable barriers were eventually incorporated along a 16 mile section of the I-15 Express Lanes, with three lanes allocated for southbound during the morning hours Monday through Thursdays. The Express Lanes operate with two lanes in each direction otherwise, with barriers relocated between 10:30 AM and 12:30 PM four days a week.

California State Route 15

Currently, Interstate 15 ends at the systems interchange with Interstate 8 near Qualcomm (Jack Murphy) Stadium. South of that point, the freeway becomes California 15. The stretch between I-8 and I-805 previously included an at-grade city arterial along 40th Street. South of Interstate 805, California 15 is freeway but not yet Interstate standard -- Caltrans is in the process of reconfiguring the California 94 (Martin Luther King Jr. Freeway, Market Street, and Imperial Avenue) interchanges and lane alignment. The state route ends just south of an interchange with Interstate 5 at 32nd Street and Harbor Drive, in the community of Barrio Logan in San Diego.

The 40th Street Corridor Project was on the books since around 1957. Construction of the corridor to Interstate standards finally got underway between 1996 (groundbreaking) and 2000. In 1997, the excavation of the freeway between El Cajon Boulevard (Business Loop I-8) and Interstate 805 began. Support pillars for the future cut and cover, one-block tunnel were erected, and grading began to create an easier grade up the hill from Interstate 8 to El Cajon Boulevard. The objective of the project, according to Caltrans District 11 Director Gary Gallegos, was to ensure that:

the image is one of motorists driving along El Cajon Boulevard, passing business after business, and with the exception of seeing the on and off ramps, never knowing they crossed a freeway.
On January 14, 2000, the freeway's northbound lanes opened to two-way traffic. By Summer 2000, the eight-lane freeway was complete and open to traffic.

Facts about the California 15 Freeway Construction Project, which was completed by the summer of 2000:1

According to Gallegos, about 40,000 vehicles per day used California 15, previously known as 40th Street, before construction of the Escondido Freeway began. Compare that number with the 210,000 motorists per day who use the congested Interstate 805 just a few miles away, many of whom switched to the section of California 15 when it opened in January 2000. This project helped improve traffic flow around the region on I-805, I-8, California 94 as well as in the immediate neighborhood. When completed, the 40th Street corridor (SR 15) became the most expensive freeway (per mile) in San Diego County.

Officially, California 15 remains signed and referred to as a "State Route". Once upgrades at the interchange with California 94 are completed, the California 15 freeway will be evaluated for inclusion into the Interstate highway system. The state route 15 will become Interstate 15 for several reasons:

  1. Original 1968 plans called for Interstate 15 to continue south to the 32nd Street Naval Station in San Diego/Barrio Logan.
  2. Several San Diego Union-Tribune newspaper articles indicate that the 40th Street corridor will become an Interstate highway rather than remain a state route.
  3. California 15 is included in the National Highway System, while some other local California freeways are not.
  4. California 15 between Interstate 5 and Interstate 8 was added as a "non-chargeable" (139b) Interstate highway in 1984.
  5. Gary Gallegos, the former Caltrans District 11 Director, referred to California 15 as Interstate 15.

History

Interstate 15 was preceded by several U.S. and state routes along its route through the Mojave Desert, Inland Empire, and San Diego regions. From the south, Interstate 15 originally was Wabash Boulevard, a city of San Diego-constructed expressway that linked to 40th Street through the urban City Heights neighborhood of San Diego. The story of the City Heights neighborhood had the missing link of Interstate 15 cutting through the heart of that community. Heading into Murphy Canyon, Interstate 15 followed the path of U.S. 395, which was later replaced with California 103 when U.S. 395 was relocated to the California 163 freeway corridor. North of Miramar, Interstate 15 generally follows Old U.S. 395, although U.S. 395 itself had been realigned from its original path onto the current Interstate 15 alignment.

Heading into Riverside County, Interstate 15 replaced U.S. 395 past Temecula into Lake Elsinore, then replaced California 71 from there northwest to Corona. At Corona, Interstate 15 replaced California 31 north into San Bernardino County. Interstate 215, meanwhile, replaced U.S. 395 and portions of U.S. 91 and U.S. 66. North of San Bernardino, Interstate 15 replaced U.S. 66, 91, and 395. Past Adelanto and Hesperia, Interstate 15 replaced Old U.S. 66 and 91. From Barstow northeast to the state line at Primm, Interstate 15 replaced U.S. 91 and U.S. 466.

The following list provides the opening dates to Interstate 15 in California (research provided by C.J. Moon based on records kept at the Caltrans District XI offices). The dates that predate 1964 are estimates and were determined based on older record keeping that was not as precise as the modern record keeping. Most of the pre-1964 segments were constructed as U.S. highways rather than Interstates, and some were initially constructed as expressways that were later upgraded to freeways.

Based on additional map and newspaper article research, the following list provides a brief history of Interstate 15 in the San Diego metropolitan area:

San Diego

Teralta Neighborhood ParkTeralta Neighborhood ParkTeralta Neighborhood ParkTeralta Neighborhood ParkTeralta Neighborhood ParkTeralta Neighborhood Park 05/13/09Teralta Neighborhood ParkTeralta Neighborhood Park wayfinder signI-15 at Teralta Neighborhood Park

A landscaped cut and cover tunnel carries Interstate 15 underneath a city block between Orange Avenue and Polk Avenue in City Heights. The lid is part of Teralta Neighborhood Park, a well used open space connected with the bicycle and pedestrian path paralleling SR 15 between Polk Avenue and University Avenue.

Los Peñasquitos Bridge

Interstate 15 crosses over Los Peñasquitos Canyon in northern San Diego via a tall, wide bridge that was built in 1976 and expanded in 2008 to accommodate the new managed express lanes project. It replaced a much older, two-lane arch bridge that carried traffic over the same canyon when this route was U.S. 395. These pictures show the much larger Interstate 15 bridge alongside the original U.S. 395 bridge. This style of arch bridge construction was very common in early Caltrans highway development in the 1920s through 1940s. Today, old U.S. 395 acts as a service road and bikepath, and it served as a construction staging area when the Interstate 15 bridge was retrofitted for earthquakes. This bridge is located just south of the Poway Road/Rancho Peñasquitos (San Diego County Route S-5) exit off Interstate 15. Each of these pictures were taken alongside the freeway bridge and on top of or alongside the old U.S. 395 bridge. As seen from the underside of the I-15 bridge, it has been expanded several times to accommodate the center reversible high-occupancy vehicle lanes and auxiliary lanes on the mainline since it was originally constructed. This bridge gained an unfortunate notoriety when motorist Cara Knott was murdered by a highway patrolman on December 27, 1986. As such, this bridge is named in her memory (as of 1995).

The date stamp shows that the Historic U.S. 395 bridge was built in 1949. This concrete arch bridge has an overall length of 434 feet. It is difficult to imagine that where a two-lane, narrow bridge once sufficed, a major bridge with over a dozen lanes is needed today to carry significant traffic flows over Penasquitos Creek.

Lake Hodges Bridge

This series of photos from January 8, 2006 shows the Interstate 15 bridge over Lake Hodges, which was under construction to incorporate the Managed Express Lanes at the time this pictures were taken. The first crossing over Lake Hodges was built in 1919, which eventually became part of California 71 and then U.S. 395. With growth in suburban areas north of San Diego, the span was replaced with a more direct bridge in the late 1960s as part of U.S. 395, and again replaced with the current structure in 1981 as I-15 was finished in San Diego County. Expansion activities were completed in 2009 with the new bridge carrying the managed express lanes.

A C Block monument is located on a right of way on the east side of Interstate 15 to the north of Lake Hodges near a bicycle/pedestrian path; it was placed back when this road was U.S. 395 ... or possibly old California 71. An extant section of Old U.S. 395 was converted to a bicycle and pedestrian path. This path includes a connection to a 2009-built Lake Hodges Bridge, which is a stressed ribbon style bridge 990 feet long and 12 feet wide. The pedestrian and bicycle bridge opened on May 15, 2009.

References:

  1. "Building An Invisible Freeway: Caltrans works with the community to lessen freeway impacts," San Diego Metropolitan Magazine, August 1999.
  2. The Dwight D. Eisenhower System of Interstate and Defense Highways: Part I - History: Additions to the Interstate System Segments Added on 12/13/68 in Accordance with 1968 Highway Act by the Federal Highway Administration (FHWA) retrieved on January 13, 2012. Of the 1,500 miles of additional Interstate highway added in 1968, the state of California received 109.6 miles of proposed Inter state routes as a result of this legislation: Interstate 15 from Colton south to San Diego (102.5 miles), the Interstate 380 spur to San Francisco International Airport (1.6 miles), and an extension of Interstate 605 from Interstate 10 to Interstate 210 via proposed California 243 (5.5 miles).
  3. 'Reversible' Freeway Lanes Opened in Test by Douglas Shuit, Los Angeles Times, October 20, 1988, which states: "Gov. George Deukmejian unveiled the newest twist in freeway driving Wednesday: special "reversible express lanes" that will be tested along an 8-mile stretch of Interstate 15 in north San Diego County. The two reversible lanes, part of Deukmejian' plan to ease traffic congestion in California, will be closed to all but southbound traffic during peak morning hours and then will be limited to northbound traffic during afternoon rush hours. Traffic on the special lanes will be limited to buses, vans, cars with two or more passengers and motorcycles."
  4. Traffic Reduction Prompts Caltrans to Call I-15 Car-Pool Lane a Success by Leslie Wolf, Los Angeles Times, May 12, 1989, which states: "Six months have passed since the opening of the express lanes on Interstate 15, and state transportation officials are ready to declare the $31-million project a success. The county' only computer-controlled reversible express lanes opened along an 8-mile stretch of I-15 last October."
  5. I-15 Express Lanes retrieved from the San Diego Association of Governments (SANDAG) webpage on January 13, 2012. This pages states, "The first phase from SR 56 to Rancho Bernardo Road opened in September 2008. The second phase from Rancho Bernardo Road to Centre City Parkway opened in early 2009. The North Segment and the South Segment opened to traffic in 2011 and 2012, respectively."
  6. Last leg of I-15 express lanes dedicated, opens January 16 by Robert J. Hawkins, San Diego Union-Tribune, January 12, 2012. A subsequent article ("Final portion of I-15 widening unveiled") that appeared in print in the same newspaper on January 13, 2012, stated: "The $1.3 billion project was partly funded by the half-cent TransNet sales tax."

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Page Updated Saturday January 14, 2012.