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High Desert Corridor

  • Overview
  • Background
  • Project Alternatives
  • Process
  • Photos

The High Desert Corridor (HDC) project is considering construction of a new multi-modal link between State Route (SR)-14 in Los Angeles County and SR-18 in San Bernardino County. This project would connect some of the fastest growing residential, commercial and industrial areas in Southern California, including the cities of Palmdale, Lancaster, Adelanto, Victorville and the Town of Apple Valley. While recent economic conditions have slowed growth throughout California, projections show that there will be significant growth in the HDC area again in the future.

In anticipation of this future growth, combined with existing congestion on east/west corridors such as I-210, I-10, SR-60 and SR-138, the California Department of Transportation (Caltrans) and the Los Angeles County Metropolitan Transportation Authority (Metro) partner agencies initiated the HDC Environmental Impact Statement/Report (EIS/EIR) in September 2010. The purpose of this environmental effort is to study alternatives for improving traffic congestion, goods transportation, and air quality in the region.

Goals of the project include:

  • Address current and future regional growth
  • Improve east-west mobility
  • Enhance safety
  • Improved connections between regional airports and efficient movement of goods

Project Status

During spring 2012, the Metro Board of Directors recognized the HDC as a “Strategic Multipurpose Corridor” that may be able to additionally accommodate a highway, a green energy production and/or transmission facility, a High Speed Rail (HSR) feeder service line from Victorville to Palmdale, and a bikeway. The addition of these new components to the original study has resulted in the need to update and refine specific technical studies, which are already underway.

New components of the HDC Strategic Multipurpose Corridor include: 

Rail - Recognizing the HDC as a multipurpose corridor with potential to connect to the ever-growing regional rail system, further studies will examine the potential for a High Speed Rail (HSR) Feeder service between Palmdale and Victorville. This feeder service would have the potential to connect to the XpressWest System – a planned high-speed rail service from Victorville to Las Vegas. Towards this goal, the HDC team is already conducting studies to identify viable routes to connect to both the Metrolink station in Palmdale, and the future XpressWest station in Victorville. In essence, the HDC project has potential to provide a one-seat rail trip from Las Vegas to Victorville and Palmdale.

Green Energy Production /Transmission Facility - The new HDC environmental studies will explore opportunities for a sustainable and environmentally responsible project, particularly through use of wind and solar energy. If proven viable, the HDC may be able to use green energy and contribute to state greenhouse gas reduction goals. 

Bike Route - Another exciting component to the HDC Multipurpose Corridor project is an effort to enhance bicycle facilities along the HDC, approximately from 100th St. to US-395. Coordination has already started to identify local routes for an ideal bike connection between the City of Palmdale and the Town of Apple Valley.


The HDC was originally proposed in the 1970s as a metropolitan by-pass for trucks to alleviate truck traffic in the Los Angeles Basin and to facilitate truck movement from Mexico to points north and east. In 2004, the Metro Board adopted the North County Combined Highway Corridor Study that recommended strategies for addressing the high volume of truck traffic traveling north and south on the I-5, SR-14 and SR-138 Freeways. The HDC was one of the preferred strategy improvements for some of the following reasons:  

  • The High Desert communities in the northern Los Angeles and San Bernardino Counties are some of the fastest growing subregions in Southern California
  • Both counties have experienced tremendous growth and demographic changes in the last 20 years
  • The rapid growth has caused travel demands to exceed roadway capacity resulting in deteriorating east-west travel speeds for an area that is served primarily by two-lane rural highways

In April 2010, the Metro Board authorized entry into a Memorandum of Understanding (MOU) for the implementation of the HDC Project. Metro is working on an MOU with the High Desert Corridor Joint Powers Authority (HDCJPA), the Southern California Association of Governments (SCAG), the San Bernardino Associated Governments (SANBAG), the State of California represented by the Department of Transportation (Caltrans) Districts 7 and 8, the County of Los Angeles and the County of San Bernardino represented by their respective Departments of Public Works, and the Cities of Lancaster, Palmdale, Victorville, Adelanto and the town of Apple Valley for the implementation of the HDC. Caltrans will serve as the lead agency for the environmental clearance. 


HDC Functional Alternatives and physical variations carried forward for further study in the Draft EIS/EIR:

No Build Alternative

The No-Build (No Action) Alternative is exactly as it sounds – it proposes that no new corridor be built. Simply, the No-Build alternative represents future travel conditions without the HDC project, and is the baseline against which the other alternatives are measured. 

Transportation System/Demand Management (TSM/TDM) Alternative

The TSM/TDM alternative proposes a collection of several smaller, lower cost roadway improvements throughout the project area, rather than a singular large, new corridor. The TSM/TDM alternative focuses on making minor improvements that would connect SR-14 with SR-138, and then extend east to connect with US- 395, I-15 and SR -18. These smaller elements would include:

  •   An eight-lane grade-separated freeway from SR-14 to 30th St East.
  •   A transition to a four-lane at-grade expressway from 30th St East to Longview Rd.
  •   A four-lane at-grade highway connecting to SR-138 and extending east to US-395 along SR-18.
  •   A six-lane arterial highway along SR-18 (Palmdale Rd) from US -395 to I-15.
  •   Minor roadway and signal improvements along SR-18 from I-15 to Bear Valley Rd.

Except for the freeway portion between SR-14 and 30th St East, these TSM/TDM roadway improvements would maintain at-grade intersections with local roads and driveway access.

Freeway/Expressway Alternative (Avenue P-8, I-15 and SR-18) (With 4 Variations)

This Alternative consists of a combination of a controlled-access freeway and an expressway.  It generally follows Avenue P-8 in Los Angeles County, and south of El Mirage Rd in San Bernardino County, later extending to Air Expressway Rd near I-15 and curving south to terminate at Bear Valley Rd. This alternative, unlike the previous two, will also consider incorporation of green technologies and a new bike route.

There are four slight variations that are being considered for this alternative, each representing a difference in how the freeway/expressway would curve and bend throughout the alignment:

  • Variation A
    • Near the City of Palmdale, the freeway/expressway would dip slightly south of the main alignment, approximately between 15th St East and Little Rock Wash.
  • Variation B (south)
    • East of the county line, the freeway/expressway would flare out slightly south of the main alignment between Oasis Rd and Coughlin Rd.
  • Variation D
    • Near the community of Lake Los Angeles, the freeway/expressway would dip slightly south of the main alignment, just south of Avenue R approximately between 180th St East and 230th St East.
  • Variation E
    • Near the cities of Adelanto and Victorville, the freeway/expressway would dip south of the federal prison.

Freeway/Tollway Alternative (Avenue P-8, I-15 and SR-18)

This Alternative follows the same physical alignment as the Freeway/Expressway Alternative with the addition of sections of the alignment operating as a tollway. The incorporation of green energy technologies and a bike route will also be considered.

Freeway/Expressway Alternative with High Speed Rail Feeder Service 

This Alternative is the same as the Freeway/Expressway Alternative, with the addition of a High Speed Rail (HSR) Feeder Service between Palmdale and Victorville. The incorporation of green energy technologies and a bike route will also be considered in this alternative.

Freeway/Tollway Alternative with High Speed Rail Feeder Service

This Alternative is the same as the Freeway/Tollway Alternative, with the addition of a High Speed Rail (HSR) Feeder Service between Palmdale and Victorville.  The incorporation of green energy technologies and a bike route will also be considered.

Hybrid Corridor Alternative

This Alternative would consist of a combination of all of the previously identified alternatives – resulting in a solution that is pieced together to best fit the needs of each section of the corridor. The determination of which elements to use, and at which locations, would be based on the results of the traffic study, environmental studies, and public input. 

Further details on the alternatives are available at the project website, metro.net/hdc.

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Study Process

The project development process is defined by federal and state environmental requirements. The following flow chart highlights the major milestones in the process from beginning to end. Currently the project is in the Draft Environmental Impact Statement/Report (DEIS/R) study phase. 

  • Anticipated release of the Draft EIS/EIR- Summer 2014
  • Anticipated Public Hearings- Fall 2014
  • Anticipated release of the Final EIS/EIR- Spring 2015

hdc process flowchart



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