Kathy Furgang - Zoom in on Superhighways

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SUPERHIGHW A YS

Kathy Furgang

The first roads were dirt and meant for slow travel.

ZOOM IN ON SUPERHIGHW A YS

States is connected with highways. ousands of miles of highways connect small towns to big cities. Superhighways allow for high-speed travel over long distances.

Early Roads

Roads have been an important part of the countrys growth. In the early days, rough landscape made it hard for horses and carriages to make it over long distances. Roads had to be dug with each new area that people settled.

The First Highways

In the 1750s, George Washington helped build a road through a forest in Ohio. Between 1811 and 1834, the 820-mile National Road replaced it. e strip connected Illinois, Indiana, Maryland, Ohio, Pennsylvania, and West Virginia. is made traveling easier, faster, and safer. e road also allowed people to settle new areas and move supplies.

A Growing Nation

Aer cars became popular in the early 1900s, there was a need for more roads. ere were so many areas to connect!

Miles of Open Road

Today, highways run through both rural and city areas. There are close to 47,000 miles of interstate highways in the United States.

It was important that the roadways were smooth for the cars to travel on.

By the 1950s, America was growing fast. President Dwight D. Eisenhower

signed the Federal-Aid Highway Act of 1956. is gave money to states to build highways. Missouri, Kansas, and Pennsylvania all got to work right away. ey planned and built the rst modern interstate highways.

In 1954, President Eisenhower signed a bill to give money to building a better highway system.

Planning Is

Key

ere are several stages to making a highway. e rst step is to plan it with as much detail as possible. Surveyors are people who measure the exact distances between points of the land. ey measure the exact dierences in heights of the landscape. is is important when planning roads so they are not too sloped, or slanted.

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An engineer looks over plans for a new road. Careful planning is the rst step in making superhighways.

Planning Is Key

Built for Speed

In Germany, there is a highway called the Autobahn. Sections of this 8,047 mile (12,950 km) system of roads have no speed limits at all.

When building roads, sometimes nature is aected. Trees may be cut down. Scientists and engineers present designs about what they think should be done. ere may be many changes before the plans are approved for construction.

Building Highways

ere are many materials used to build highways. Aer the soil is smoothed and packed down, about 21 inches of natural

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Workers place asphalt as the top layer of a new road.

Planning Is Key

material is laid down along the entire path. is material, called natural aggregate , is made of sand, gravel, and crushed stone. On top of the aggregate is about 11 inches of concrete and asphalt roadway. is is the part that vehicles ride on.

Some highways may need to pass over waterways. Some pass over other roads, or even underground for short distances. Steel beams are oen used to make bridges. e material must be strong enough to hold the load on the bridge.

Tunnels are dug with huge machines. ey drill through hard rock. e human-made materials for the tunnel last through all kinds of weather.

Safety First

One of the most important things about building superhighways is making sure that people travel safely. More than four million people are hurt each year in car accidents. ats why highway safety is so important. Engineers must plan entry and exit ramps carefully. Cars need time to change lanes safely. ey must be able to exit the highway without having to slow down too quickly.