Question of the Day - 08 March 2026

Interstate 11 (I-11) is designed, initially, to connect Phoenix and Las Vegas, the two largest U.S. cities not previously linked by an interstate.

Some people might be surprised to learn that Phoenix is the fifth largest city in the nation. That's right, it lines up behind New York, Los Angeles, Chicago, and Houston in population. It's 300 miles (exactly) between the two cities, almost entirely along US 93, which begins in Wickenburg, Arizona, and runs 1,360 miles all the way up to the border of Montana and British Columbia. Eventually, I-11 will upgrade that entire corridor, "enhancing regional transportation, stimulate economic development, and facilitate trade between Mexico, the U.S., and Canada," according to the Arizona Department of Transportation. It will definitely reduce congestion and improve driving safety between Phoenix and Vegas. 

Meanwhile, US 95 parallels US 93 to the west, from the Mexico-California to the Idaho-B.C. borders. The two highways converge near Boulder City, then go their separate ways at the Spaghetti Bowl in Las Vegas. (US 95, by the way, is the longest highway in Nevada, 647 miles long, about the distance from Boston to Raleigh, North Carolina, crossing seven states en route. 

The first short stretch of the I-11, the country's newest interstate, opened in 2018. It runs from the Arizona border, near the middle of the Mike O'Callahan-Pat Tillman Bridge near Hoover Dam, to the Henderson interchange of 215 west and 515 north. It was built over a number of years and cost $338 million, which gives you an idea of how much an interstate proposed to cover nearly 500 miles from Nogales, Arizona, on the Mexican border to Las Vegas, then another 1,100 miles to the Canadian border, will cost overall.

When I-11 replaces US 93, it will hardly be the first time an interstate has taken over a US highway.   

US 40 was almost entirely supplanted by I-80. US 66 turned into I-40, I-44, and I-55. US 99 in California was heavily bypassed by I-5, with some remaining sections being considered for future Interstate designations. US 11 was largely replaced by I-81 in the eastern U.S. The Connecticut Turnpike was designated I-95, the Pennsylvania Turnpike as I-76 and I-70, the New York Thruway as part of I-87, I-90, and others, etc. So in due time, the US 93/95 designations in southern Nevada will be completely subsumed by I-11.