Interstate 5

US 99 (1961)

Dead-Man's Curve in Lebec, California, 2010

Interstate 5 and Interstate 90 interchange, seen from Columbia Center (2022)

SanYsidroBorderCrossingByPhilKonstantin

Peace Arch, U.S.-Canada border

Interstate 5 (I-5) is a major north-south Interstate Highway in the United States, stretching from the Mexican border at San Ysidro, California, through the Western United States to the Canadian border near Blaine, Washington. As one of the primary highways on the West Coast, it serves a significant role in the transportation infrastructure, facilitating both domestic and international trade, as well as passenger travel.

Route Description

I-5 runs through the states of California, Oregon, and Washington. It begins at the San Ysidro border crossing, heads north through major cities including San Diego, Los Angeles, and Sacramento in California; Portland, Oregon; and Seattle, Washington, before reaching its northern terminus at the Peace Arch border crossing in Blaine, Washington.

In California, I-5 traverses the agricultural Central Valley, crosses the Tehachapi Mountains, and navigates through several major urban centers. The highway is known for its heavy traffic, especially in the Los Angeles area. Northward, in Oregon and Washington, it passes through more varied landscapes, including forests, farmlands, and major urban centers.

History

The construction of I-5 was authorized by the Federal-Aid Highway Act of 1956, with the goal of creating a seamless highway system to improve the movement of military equipment and personnel, as well as to facilitate general transportation and commerce. The highway was completed in sections, with the final segment opening in the 1970s.

Major Junctions

I-5 intersects with several other major highways, including I-10 and I-8 in California, I-84 in Oregon, and I-90 in Washington. These intersections are crucial for facilitating east-west travel across the Western United States and for connecting I-5 to other parts of the country.

Impact

The impact of I-5 on the regions it serves has been significant. It has stimulated economic growth by improving access to ports, cities, and agricultural areas. However, it has also faced criticism for contributing to urban sprawl, environmental degradation, and traffic congestion, particularly in densely populated areas.

Future Developments

Various projects are underway to improve I-5, including widening sections of the highway, improving interchanges, and enhancing safety features. These efforts aim to address the challenges of increased traffic volume and to support the continued growth of the West Coast economy.

See Also

• Interstate Highway System
• Transportation in the United States
• U.S. Route 99 (the predecessor to much of I-5 in California)