Controlled-access highway

These are very fast roads.

Cars drive on them quickly. They do not have stop lights. They do not have crossings for people.

There are no houses next to them. A strip of grass or a wall keeps the two sides apart. This helps cars move fast and stay safe.

People use special ramps to get on or off. These roads help many cars travel long ways.

Controlled-access highways are special roads built for fast travel.

People call them freeways, motorways, or expressways. These roads are designed to keep traffic moving smoothly. They do not have traffic lights or stop signs. They also do not have crossings for people or trains. Instead, bridges or tunnels carry other paths over or under the road.

To keep drivers safe, these roads use a median strip. A median strip is a divider between the two sides of traffic. It might be a wall or a patch of grass.

This prevents cars from hitting traffic going the other way. Drivers enter or exit using ramps, which are called slip roads.

These ramps help drivers change speed safely.

These roads started growing in the early 1900s. Italy built the first one for fast cars in 1924. Germany later built the first large system of these roads. In North America, the first parkways opened near New York City. Today, many countries use huge networks of these fast roads.

Controlled-access highways are special roads built for fast travel.

People use different names for them. You might hear them called freeways, motorways, or expressways. These roads are made to keep traffic moving smoothly. They are designed to carry many vehicles at high speeds. This helps people travel between cities or through large cities quickly. They are very important for moving people and goods across long distances.

These roads work by controlling how vehicles enter and leave.

There are no traffic signals or intersections on the road. You will not find stop signs or driveways here. Instead, drivers use ramps, also called slip roads, to join the highway. These ramps help drivers change their speed safely.

To keep people safe, a median strip separates the two sides of traffic. This divider might be a patch of grass or a barrier. It prevents cars from hitting traffic going the other way.

Other paths do not cross the highway at the same level.

If a railway or another road meets the highway, it uses an overpass or an underpass. This means the path goes over or under the highway. This design stops conflicts between different types of traffic. It also keeps the flow of cars steady and unhindered. This way, there is no need to stop for pedestrians or trains.

These types of roads began to change in the early 1900s. Italy was the first country to build them for fast motor vehicles. They opened the A8 road in 1924 to connect Milan to Varese. Germany also built important roads during this time. They built the AVUS in Berlin, which was a closed circuit for testing. In 1932, a road between Cologne and Bonn became a dual highway. This was one of the first roads without speed limits.

Many places around the world use these road systems today.

In North America, the first parkways opened near New York City in the 1920s. Canada has the Queen Elizabeth Way, which used a cloverleaf interchange. The Highway 401 in Canada is now a very busy highway. Many countries even use international systems to number their routes. These roads link many different towns and countries together. They help our modern world stay connected and moving.

A controlled-access highway is a specialized roadway designed for high-speed vehicular traffic.

Unlike standard streets, these roads regulate all traffic flow, including how vehicles enter and exit. They are known by many names depending on where you live. Common English terms include freeway, motorway, and expressway. Other names include throughway, thruway, or parkway. These roads are vital because they allow for the rapid movement of people and goods across long distances. They provide high-capacity travel for both crowded urban areas and rural regions.

The mechanism of a controlled-access highway relies on the total regulation of traffic movement.

To maintain high speeds, the design eliminates at-grade intersections. This means there are no traffic signals, stop signs, or crossroads where paths meet on the same level. Instead, other roads, railways, or pedestrian paths use overpasses or underpasses to cross safely. Entrances and exits are managed through interchanges using slip roads, which are also called ramps. These ramps allow drivers to change their speed smoothly when transitioning between the highway and arterial or collector roads.

Safety is maintained through specific structural features and strict usage rules. Opposing directions of travel are generally separated by a median strip, also known as a central reservation. This median may consist of a grass area or a physical traffic barrier.

By eliminating conflicts with oncoming traffic, these highways dramatically increase both safety and traffic capacity. In many countries, such as those following the Vienna Convention, motorways have specific rules. For example, walking, parking, and certain types of vehicles like animals or bicycles are often forbidden. In some regions, there are also minimum and maximum speed limits to ensure steady flow.

There are different ways to classify these roads based on their design and purpose. The term "limited-access highway" can refer to roads with somewhat less isolation from other traffic. In the United States, the term "freeway" is sometimes split into two categories. Freeway A describes major roadways with high traffic volumes and complex visual environments, often found near metropolitan cores. Freeway B refers to other divided roadways with full access control that require lighting. In the European Union, a distinction is often made between motorways and expressways. A principal arterial might include motorways or expressways that serve long-distance, interurban movements.

The history of these highways began to evolve during the first half of the 20th century. Italy was the first nation to connect cities with controlled-access highways reserved solely for fast motor vehicles. In 1924, Italy opened the A8, which connected Milan to Varese. Germany also played a major role in this development. They built the AVUS in Berlin, which opened in 1921 as a closed circuit for testing and racing. By 1932, Germany completed a road between Cologne and Bonn that functioned as a dual highway without speed limits. This helped form the first nationwide highway system in the country.

North America also saw early developments in this field. The first North American parkways opened in the New York City area during the 1920s. The Long Island Motor Parkway, which opened in 1908, was the world's first limited-access roadway. While it featured modern elements like banked turns and guard rails, it was not a true controlled-access highway because drivers could still turn left across oncoming traffic. In Canada, the Queen Elizabeth Way became a significant route by using cloverleaf and trumpet interchanges. Today, Canada's Highway 401 has grown to become the busiest highway in the world.

Controlled-access highways connect to much larger global and regional systems. Many nations utilize national-level or even international-level route numbering. For example, the European E route system helps organize travel across borders. These networks are essential for modern infrastructure, linking urban centers to rural landscapes. They allow for the collection of long-distance traffic from various roads, which prevents local traffic from causing delays. By separating different types of travel, these systems create an efficient web of movement that supports modern economies and travel needs.