While the bulk of the battery-electric and plug-in hybrid cars sold today have a range of less than 100 miles, that doesn't stop some owners from using them for longer trips.
The secret is to use DC quick-charging stations, which can recharge an electric car'sbattery pack to about 80 percent of capacity in half an hour or less.
Planned as early as 2009, the first charging stations opened in December 2011.
The full length of the highway in the two states has been operational for a year or so now, and the Eugene Register-Guard notes that several usage records were set last year.
The Electric Highway is simply a network of fast-charging stations, spaced every 25 to 50 miles, along parts of Interstate 5 in Oregon and Washington.
The state of Oregon has added other routes popular with residents and tourists to the Electric Highway as well, including the coastal Highway 101 and Interstate 84 through the Columbia Gorge.
Altogether, the state of Oregon has 43 fast-charging units along its portion of the Electric Highway.
Last month, the US Energy Information Agency noted in a blog post that the two states now see a far higher percentage of the nation's fast-charging sessions than average.
The agency wrote:
Washington and Oregon now have about 5 percent and 4 percent, respectively, of the nation's total public charging stations, despite having only about 2 percent and 1 percent of the nation's total light-duty vehicles.
From March 2012 through April 2014, PEV drivers recharged 17,917 times in Washington and 18,522 times in Oregon, mostly using fast chargers.
Fast-charging stations are far less common than the less expensive and slower 240-Volt Level 2 charging stations, which take at least 4 hours to recharge a depleted electric-car battery.
And there are three different standards: CHAdeMO, which is used primarily by the Nissan Leaf; Supercharger, which is only for Tesla cars; and Combined Charging Standard, or CCS, which is now the least common and used primarily by the BMW i3.
Most new fast-charging sites are now being built with two different cables, one for CHAdeMO and one for CCS. Tesla Supercharger sites are entirely separate, and are funded and operated by Tesla Motors itself.