America’s 5 Fastest Roads

Althea Chang
July 29, 2011
Ronald Groenendijk / Flickr
Ronald Groenendijk / Flickr

Summer driving doesn’t always mean spending hours sitting in traffic and crawling along the interstate on the way to the beach. On the fastest highways in America, some drivers are blazing down stretches of open road at more than 90 mph.


The fastest car on the fastest road in America clocked in at 94 mph heading northbound on Arizona’s Route 79 between Saguaro National Park and Phoenix earlier this year, according to INRIX, a traffic data company that tracks speeds using vehicle GPS data. On this 39-mile stretch — two lanes wide and almost completely straight for its entire length — the fastest drivers regularly reach speeds of 87 to 90 miles per hour. Arizona’s speed limit is 75 mph on rural interstates and 65 mph on urban interstates.

To determine America’s fastest roads, INRIX first looked for stretches of roadway where motorists routinely floor it, then it found the speed range at which each roadway’s fastest 5% of drivers travel. INRIX multiplied that figure by the length of each road to decide the final ranking. The result is a list of roads where drivers put the pedal to the metal over fairly long distances. Inrix counts the same road separately in different travel directions.

INRIX drew information from its crowdsourced Smart Driver Network, which consists of anonymous GPS data points gathered from from 5 million drivers in consumer and commercial vehicles nationwide, from January through June 15.

This year’s fastest drivers are going a bit slower across the board: The average speed across the 10 fastest roads in America was 81 mph, compared to an average of 85 mph during the same period in 2010.

“High gas prices are slowing drivers down,” says INRIX spokesman Jim Bak, who thinks drivers are putting on the brakes to improve fuel economy.

Tom Kloza, an oil and gas expert at Oil Price Information Service, thinks a more likely explanation is that high gas prices are working in concert with the poor economy and high unemployment to keep more young drivers — who tend to speed and engage in the riskiest driving behavior — off the road.

Demand for gasoline in America has fallen since last year, notes Kloza, who thinks cash-strapped drivers between the ages of 16 and 25 may be cutting down on driving based on necessity. Those who are left on the road could be older, and thus slower.

Another factor: police appear to be working harder to enforce the speed limit. On Arizona’s Route 79, Tim Gaffney, spokesman for the Pinal County Sheriff’s Office, which covers the highway’s particularly speedy stretch, says gas prices and “heavy speed enforcement details” have impacted how people are driving.

While Americans aren’t exceeding speed limits as much as they were last year, INRIX says they seem to be going faster on the home stretch.

“As drivers travel slower on average to conserve fuel, we see them going faster at the end of trips as they try to make up time,” says Bak. “Many of our fastest roads this year are on open stretches just before entering major urban centers.” And on stretches of road just outside chronically congested areas like Los Angeles and New York City, traffic is also moving much faster than normal, Bak adds.

Here are the 5 fastest roads in the United States where motorists are driving at full throttle:

5. Arizona State Route 77
Heading North out of Tucson up to the AZ-76/Redington Road interchange near San Manuel Airport

Average speed of fastest 5%: 81 mph
Top speed clocked by INRIX: 81 mph
Length of corridor: 4.8 miles

4. Eastbound MI-5 Michigan Highway
Heading into Detroit from the I-275/I-96 interchange to Telegraph Road

Average speed of fastest 5%: 81 mph
Top speed clocked by INRIX: 83 mph
Length of corridor: 4.9 miles

3. California State Route 73
In both directions between Moulton Parkway and Bear Street

Average speed of fastest 5%: 81 mph
Top speed clocked by INRIX: 85 mph
Length of corridor: 14.8 miles

2. Oklahoma State Highway 33
In both directions just Northwest of Oklahoma City

Average speed of fastest 5%: 83 mph
Top speed clocked by INRIX: 87 mph
Length of corridor: 24

1. Northbound Arizona State Route 79
Between Saguaro National Park and Phoenix

Average speed of fastest 5%: 88 mph
Top speed clocked by INRIX: 94 mph
Length of corridor: 17.6 miles

Full list: America's Fastest Roads