President Eisenhower considered passage of the Federal Highway Act of 1956 his greatest accomplishment. The law provided funding for construction and completion of the nation’s Interstate Highway System, now officially named for “Ike,” and generally regarded as the greatest public works project in history—greater even than the system of aqueducts Romans constructed across Europe. In 2006, the United States celebrated “The Year of the Interstate,” but every day millions of Americans merge into traffic on the great four-lanes, quietly paying homage to the mighty concrete tapestry Eisenhower wove across the land.

Mark your maps.

Traveling the Interstate highways, you can track your mileage, log your trivia, and mark the major milestones…

• by the numbers. All of the major east-west routes end in zero—I-10, I-20, I-40, I-70, I-80, and I-90. Any interstate that end in an even number goes from east to west. Similarly, major north-south routes end in 5, most notably I-5 and I-15 along the west coast and I-95 on the east coast. All the Interstates that end in odd numbers go north and south. Segments with triple digits generally connect major Interstate highways in the nation’s largest cities. The entire Interstate Highway system forms a grid across the country, and the numbers increase as they go from west to east and south to north. No Interstate highway numbers correspond or conflict with U.S. highway numbers in the same state except in places where the Interstate links to the U.S. highway.

• according to distances. The five longest Interstates stretch all the way across the country from west to east. I-90, the longest, goes from Seattle to Boston. Seven Interstates go all the way from major southern cities nearly to the Canadian border. I-95, one of the nation’s most heavily traveled roads and arguably its most important commercial route, runs the length of the seaboard from Miami, Florida to Houlton, Maine, covering nearly 2000 miles. On the west coast, Interstate 5 stretches from San Diego to Blaine, Washington, often offering travelers spectacular views of the Pacific Ocean. By contrast, five segments of Interstate highway measure less than a mile long.

• noting elevations. In Colorado, at the Eisenhower Tunnel and the Clear Creek Summit, I-70 travels to well over 11,000 feet. Just east of the summits, an exit goes directly to world class skiing at Vail. Near El Centro, California, Interstate 8 drops to 52 feet below sea level, and daytime summer temperatures frequently reach over 120?F.

• checking over- and under-passes. The system includes 55,512 bridges, the most beautiful of which spans Interstate 15 just south of Riverside, California. Constructed by an ancient principle—the simple arch, this one breathtaking bridge has collected almost as many design awards as all the other bridges combined.

• watching for…oops. Five state capitals have no nearby Interstate highway—Juneau, Alaska; Dover, Delaware; Jefferson City, Missouri; Carson City, Nevada; and Pierre, South Dakota. In 2012, Interstate 580 will connect Carson City, Nevada to I-80, but transportation officials have no plans to connect the four other capitals to major Interstates.

The Interstate highway system marks one of the United States’ major feats of engineering and public works initiative, but heavy semi-trailer traffic has taken a serious toll on many of the major commercial routes. During the late 1990s and early in the new millennium, various Congressmen introduced legislation authorizing renovation and resurfacing for the most historic and most important stretches of Interstate highway, but all the bills bogged-down in partisan politics. As the system approaches its sixtieth anniversary, officials hope they can find initiative and means to restore the historic highways to their original majesty.

Robert Wilkes is an on the road freelance blogger for TruckersReport as well as a regular poster on their Truckers Forum.