WASHINGTON—There's a lot to celebrate about the U.S. interstate highway system, which turns 50 on Thursday.
For one thing, here's the number of traffic lights on its 47,000 miles: zero. For another, here's the minimum lane width: 12 feet. And the minimum right shoulder width: 10 feet. That's three reasons that interstates, mile for mile, are twice as safe as all other U.S. roads.
Here's more on the country's main arteries, which President Dwight Eisenhower championed as a means of moving military materiel quickly from coast to coast:
_Interstates make up just 1 percent of total U.S. road miles, but they carry a quarter of all traffic and 40 percent of all truck traffic.
_About 60,000 people ride over the average mile of interstate highway daily.
_Pre-interstate, drivers could cover about 250 miles in a dawn-to-dark day on the road. Interstates doubled that.
_Why do interstates feel more congested these days? Because they are. In the past decade, their traffic volume increased 29 percent. Total interstate lane miles increased just 4 percent in the same period.
_Interstates today have a fatality rate of about 1 per 100 million vehicle miles. That compares with 2 per 100 million vehicle miles on other roads. Curved exit ramps (versus right-angle turns) and minimum speeds get much of the credit.
_Feel hemmed in by trucks when you're on interstates? That's logical. Freight distribution by truck has been growing 12 percent a year since 1956.
_What state has no interstates? Alaska. Hawaii has highways that are considered interstates because they're paid for out of the same federal fund and built to the same standards, but they're designated with an H instead of an I.
_Which cities have the worst interstate access? Buffalo, N.Y.; Dover, Del.; Fresno, Calif.; Jefferson City, Mo.; Myrtle Beach, S.C.; and Tulsa, Okla., according to the Federal Highway Administration.
For more on interstate highways, go to
The National Archives offers an account of Dwight D. Eisenhower's 1919 cross-country trip, which convinced him of the need for better national highways, in its Eyewitness series. It's at
Enter the site, click on "Contents" and then on "Lt. Col. Dwight D. Eisenhower."
(c) 2006, McClatchy-Tribune Information Services.
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