The Interstate Bridge

I-5 from Portland OR to Vancouver WA

The Interstate Bridge is actually two parallel bridges built at different times. The older bridge was opened to traffic in 1917 and was originally owned by Multnomah County OR and Clarke (now Clark) County WA. At first a toll bridge, the bridge became free in the 1920s when taken over by state government. The second bridge, downstream, was completed in 1958. Tolls were added back to the bridge in 1958 and removed in 1966.

Before the second bridge was built, the older bridge roadway carried a 4 lane two way highway. Streetcars crossed the bridge into the 1930s. All traffic was switched to the newer bridge when it first opened. The older bridge was closed for several months for renovation. The elevation of the older bridge above the river had been more or less constant from shore to shore. The newer bridge was built with a higher rise in the middle of the river to allow moderate height boats to pass beneath without the need to open the drawspan. The profile of the older bridge was modified to match the newer. When the older bridge was reopened to traffic, it became 3 lanes northbound, the newer bridge, 3 lanes southbound.

At first the Pacific Highway crossed the Interstate Bridge. In 1926, this route became US 99. Today, the highway crossing the bridge is known as I 5

This photograph was taken in September 2001 with Washington in the foreground.