Speed limit facts for kids

In 1920, a pastor was fined US$10 for driving too fast in his car.

Speed limits are rules that tell drivers the fastest speed they can go on a road. These limits are usually shown on traffic signs. They tell you the maximum speed in kilometres per hour (km/h) or miles per hour (mph). Governments set these limits to keep everyone safe. Police and courts help make sure drivers follow them. Some places, like parts of the Autobahn in Germany, don't have a set speed limit.

The very first speed limit for cars was in the United Kingdom in 1861. It was 10 mph.

As of 2018, the highest speed limit in the world was 160 km/h (about 100 mph). This was on two main roads in the United Arab Emirates. However, driving can still be dangerous there because people sometimes drive too fast.

There are many reasons for speed limits. One main reason is to make roads safer. Speed limits help reduce the number of crashes and injuries. The World Health Organization (WHO) says that controlling speed is a key way to make roads safer. About 1.3 million people die in road crashes every year.

Speed limits also help the environment. They can reduce noise, vibrations, and pollution from vehicles. Some cities have very low limits, like 30 km/h (about 19 mph). This helps with safety and makes traffic flow better.

How Speed Limits Started

An old speed limit sign from New Hampshire.

Speed limits existed even before cars! In 1652, the American colony of New Amsterdam said that wagons could not go "at a gallop." If you broke this rule, you paid a fine. In the United Kingdom, a law in 1832 made it illegal to drive too fast and put people in danger.

The UK set the first speed limits for machines like early cars. In 1861, the limit was 10 mph on open roads. This was lowered to 2 mph in towns and 4 mph in the countryside in 1865. Later, in 1896, the limit went up to 14 mph. This change is still celebrated with a yearly car run from London to Brighton.

The first person known to be fined for speeding was Walter Arnold in the UK in 1896. He was going 8 mph!

In 1901, Connecticut was the first U.S. state to set speed limits for cars. It was 12 mph in cities and 15 mph on country roads. By 1930, most U.S. states had speed limits.

In the UK, the national speed limit became 20 mph in 1903. But it was hard to check speeds without speedometers. So, in 1930, all speed limits were removed! Then, in 1934, a 30 mph limit was brought back for cities. In 1967, a 70 mph national speed limit was set.

In Australia, people were also fined for "furious driving" in the early 1900s. In 1905, one driver was caught going 20 mph past a tram.

Germany set its first country-wide speed limit in 1934. In the 1960s, some European countries set limits based on how fast 85% of drivers usually went.

In 1974, Australia changed its speed limits to use the metric system. For example, 35 mph became 60 km/h.

Sweden started a program called Vision Zero in 2010. Its goal is to have no deaths or serious injuries from road crashes.

Rules for Speeding

Speed limit units on traffic signs around the world. Most countries use kilometers per hour (km/h). The U.S. and U.K. use miles per hour (mph).

A sign in China showing maximum and minimum speed limits for different types of vehicles on a highway.

Most countries use kilometers per hour (km/h) for speed limits. But the United States and the United Kingdom use miles per hour (mph). There are no plans to change these laws right now.

Driving Safely

Most laws say that drivers must always drive at a safe speed. This is true no matter what the posted speed limit is. Drivers need to think about the road, weather, and traffic.

In Germany, the law says: "Any person driving a vehicle may only drive so fast that the car is under control." This means you must adjust your speed to the road, traffic, weather, and your own driving skills.

In France, drivers must slow down in many situations. This includes when passing people walking or biking, when visibility is low, or when the road is tricky. If drivers don't control their speed, they can be penalized.

In the United States, this is called the basic rule. It means you must drive at a speed that is safe for the conditions. For example, in California, the law says you can't drive faster than what is "reasonable" or what "endangers the safety of persons or property." This safe speed might be different from the posted limit.

Driving Too Fast

When drivers don't follow the basic safety rules, it can lead to crashes. For example, in Germany, "excessive speed" caused many crashes on highways in 2012. This doesn't always mean going over the speed limit. It means driving too fast for the conditions. Conditions like wet roads, fog, uneven roads, or heavy traffic mean you need to slow down. Crashes from driving too fast are more common on smaller, lower-quality roads.

So, there's a difference between excess speed (going over the limit) and inappropriate speed (going too fast for the conditions).

Different Types of Speed Limits

Map of the highest speed limits around the world.

Maximum speed limits in Europe in km/h.

Most countries have a maximum speed limit that applies everywhere unless a sign says otherwise. Lower limits are often shown on signs. Sometimes, streetlights or the road's design can also tell you the limit.

Speed limits are often set based on the speed that 85% of drivers choose. This idea is that most drivers are careful. However, sometimes drivers don't see all the risks, and this rule might not work perfectly.

Drivers must always follow the basic safety rule, even if the posted limit is higher.

Minimum Speed Limits

Some roads have minimum speed limits. This means you can't drive too slowly. This is usually on highways where slow speeds could be dangerous or block traffic. Minimum limits are not as common as maximum limits.

Middle Speed Limits

It's rare to have rules that limit only middle speeds. One example is on the ice roads in Estonia. Drivers are told to avoid speeds between 25–40 km/h (16–25 mph). This is because vehicles might cause vibrations that could break the ice. So, you can go under 25 km/h or between 40–70 km/h.

Variable Speed Limits

An example of a variable speed limit sign in the United States.

A digital sign showing a variable speed limit.

Variable speed limits change depending on conditions. Germany first tried these signs in 1965 on a highway. Signs could show 60, 80, or 100 km/h. They could also warn of "danger zones" or "accidents." Today, modern systems use sensors to check traffic and weather. They can change the speed limit automatically.

In the United States, variable limits are used on busy highways or in areas with extreme weather changes. For example, on Interstate 80 in Wyoming, limits change to slow traffic in bad winter weather. This has helped reduce crashes.

The UK also uses variable speed limits on parts of its motorways. This helps traffic flow better and reduces crashes.

New Zealand started using variable speed limits in 2001 on a tricky section of highway. The normal limit is 80 km/h there.

Austria tried an experiment in 2006 where speed limits could go up to 160 km/h (about 100 mph) in good conditions. But this experiment was stopped.

Roads Without Speed Limits

Just over half of the German autobahns have only an advisory speed limit. This means there's a suggested speed (130 km/h or 81 mph), but no legal maximum. About 15% have temporary limits due to weather or traffic. The rest have permanent speed limits. Other roads in Germany outside of towns usually have a 100 km/h limit.

Before 1990, East Germany had strict speed limits. After Germany reunited, more powerful cars and more traffic led to a doubling of traffic deaths. They worked hard to make roads safer, and now their rules are similar to West Germany's.

Rural roads on the Isle of Man also have no speed limits in many places. A plan to add limits for safety was not followed.

Some states in India, like Andhra Pradesh, Maharashtra, and Telangana, also don't have speed limits by default.

Many roads that used to have no speed limits got them after the 1973 oil crisis. This was to save fuel. For example, Switzerland and Austria added temporary 100 km/h limits in 1973.

A typical speed limit sign in Montana from 1995 to 1999.

Montana and Nevada in the U.S. used to rely only on the basic safe speed rule. They didn't have specific speed limits on rural roads until 1974. After federal speed laws changed in 1996, Montana went back to the basic rule. But the state's highest court said this rule was too vague. So, Montana set a 75 mph limit on rural highways in 1999.

Australia's Northern Territory had no rural speed limit until 2007, and again from 2014 to 2016.

How Speed Limits Are Set

There are different ways to decide on a speed limit:

• Engineering: Using road design and traffic flow.
• Harm Minimization: Thinking about how crashes happen and how much force the human body can handle. Countries like the Netherlands and Sweden use this.
• Economic Optimization: Balancing safety with travel time and costs.
• Expert System: Using special computer programs.

The "Operating Speed" method sets the limit near the speed that 85% of drivers choose. This can make it easier to enforce, but drivers might not always pick the safest speed. This method is used in the United States.

Making Sure Rules Are Followed

A Gatso speed camera, used to check vehicle speeds.

Speed limit enforcement is when police or other authorities check that drivers are following the rules. They use things like roadside speed checks or automated speed cameras. These cameras can even read license plates.

In the UK in 2012, 30% of drivers did not follow speed limits. In Europe, between 2009 and 2012, 20% of drivers were fined for speeding.

Many people support using devices in cars that help drivers stick to the speed limit. One way to help is by giving penalty points and fines for going slightly over the limit.

Roads can also be changed to slow traffic down. This is called "traffic calming." It includes things like narrower roads or special signs. Some cities, like Munich, design roads so drivers naturally go at the right speed without needing many signs.

Why Speed Limits Are Important

Speed limits are mainly set to keep roads safe. They also help with travel time and how easily people can move around. Sometimes, limits are used to save fuel or help the environment by reducing pollution.

Road Safety

The Pan-American Highway has a barrier in the middle and no obstacles, making it safer for high speeds.

The World Health Organization reported in 2004 that road crashes caused 22% of all injury deaths worldwide. They said that vehicle speed was "at the core of the problem." They suggested setting proper speed limits and making roads and vehicles safer. Road crashes are the main cause of death for children aged 10–19.

Maximum speed limits help keep all cars on the road going at similar speeds. This is important because crashes are more likely when some cars go much faster or slower than others. The risk of a crash getting worse (like causing a death) goes up very quickly with speed.

Traffic calming measures can help slow down cars on local roads.

It's good to reduce vehicle speeds because the energy in a crash increases a lot with speed. A crash at higher speed is much more dangerous.

Motorways usually have higher speed limits than regular roads. This is because motorways are designed to be safer. They separate traffic going in opposite directions, have barriers, and don't allow pedestrians or bikes. Germany's highways show this: fewer people die per crash on autobahns than on rural roads.

A 2009 report found that "exceeding posted speed limits" was a factor in about 55% of fatal speeding-related crashes. "Driving too fast for conditions" was a factor in 45%. However, the report didn't say if these factors caused the crash. Other research suggests that only a small number of crashes are directly caused by drivers going over the speed limit.

Roads are designed for a certain "design speed." This is the speed used to plan the road's features. However, cars can often go faster than the design speed without being unsafe.

The Vision Zero program suggests maximum safe speeds based on the road type and how much force the human body can handle:

Roads where cars can only hit barriers are very safe. They have barriers between traffic, limited entry points, and no slow users like pedestrians. Rural roads without barriers can be very dangerous, even with lower speed limits. For example, in 2011, German rural roads had a much higher death rate than autobahns.

In 2018, a group called IRTAD WG also suggested safe speed limits based on what the human body can survive:

Saving Fuel

Saving fuel can also be a reason for speed limits. The United States set a national maximum speed limit of 55 mph (89 km/h) in 1974. This was during the 1973 oil crisis to reduce how much fuel was used. However, some groups later said this law didn't save much fuel and was often ignored.

Helping the Environment

Speed limits can also help with air quality and other environmental issues. The European Union uses speed limits more and more for environmental reasons. Studies show that lower speeds for trucks lead to less CO₂ pollution and better fuel use.

People's Opinions

Speed limits have always been a topic of debate. Different groups and people either support or oppose them.

Against Speed Limits

Some groups have always been against speed limits. In the UK, a group called the Motorists' Mutual Association started in 1905 to warn drivers about speed traps.

More recently, groups want to remove certain speed limits or enforcement methods. For example, automated speed cameras have been criticized by groups like the Association of British Drivers.

Arguments against strict speed limits include:

• A 1994 study suggested that higher speed limits might make traffic move to safer roads.
• A 1998 article said that when speed limits are too low, it can make roads less safe. This is because cars might tailgate or weave more.
• A 2007 petition in the UK asked to remove speed cameras. It said their benefits were exaggerated and they might even cause more crashes.
• In 2008, the German Automobile Manufacturer's Association said that general limits were "patronizing." They preferred variable speed limits. They also said that raising limits in Denmark and Italy didn't make roads less safe.
• A 2010 report from the ADAC (German Auto Club) said that a speed limit on autobahns wasn't needed. They pointed out that many countries with limits had worse safety records than Germany. However, newer information shows Germany is in the middle compared to other European countries for highway deaths. Since 2020, the ADAC is "no longer in principle" against a speed limit on autobahns.

Speed Limit Signs

A stack of rectangular speed limit signs.

A German border sign showing speed limits: 50 km/h in towns, 100 km/h in rural areas, and a suggested 130 km/h on the Autobahn.

Most countries use kilometres per hour for speed limits. But the United Kingdom, United States, and a few smaller countries use miles per hour. Signs in Samoa show both units.

There are two main designs for speed limit signs:

• The Vienna Convention on Road Signs and Signals uses a white or yellow circle with a red border. Most of the world uses this.
• The Manual on Uniform Traffic Control Devices (MUTCD) from the U.S. uses a white rectangle with the words SPEED LIMIT. The U.S., Canada, and some other places use this style.

In most of the U.S., signs say SPEED LIMIT. But in Alaska and California, they often say MAXIMUM SPEED. Canada uses signs with MAXIMUM. Australia, Mexico, Panama, and Peru use rectangular signs but put the number in a red circle.

In the European Union, big signs showing national speed limits are usually placed right after border crossings. Sometimes, smaller reminder signs are painted on the road.

Maximum Speed Limit Signs

A speed limit sign in Germany showing 60 km/h.

In France, city signs mean the speed limit is 50 km/h. The "50" sign here is just a reminder.

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  Speed limit sign for 50 km/h (most of the world)

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  UK sign for 50 mph

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  Australia sign for 50 km/h (rectangular)

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  Sweden, Finland, and Iceland use an amber background.

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  Ireland includes "km/h" since 2005.

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  Indonesia includes "km" in the corner.

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  Japan uses blue numbers.

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  Samoa shows both miles per hour and kilometers per hour.

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  UAE and Saudi Arabia use both Western and Eastern Arabic numbers.

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  Canada (km/h)

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  Canada (Ontario)

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  Canada (Yukon and British Columbia)

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  United States (mph)

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  United States (Oregon version)

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  United States (New York version)

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  United States (metric version, rarely used)

Some speed limits apply to a whole area, called a "zone."

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  Zone 30 entry in Germany (30 km/h).

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  Zone 30 end in Germany.

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  Zone 30 entry in France (30 km/h).

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  Zone 30 end in France.

Minimum Speed Limit Signs

A UK minimum speed limit sign (mph).

Minimum speed limits are often shown with blue circle signs. In the U.S., they look like maximum speed signs but say MINIMUM SPEED. Some countries like Argentina use a red border. Japan and South Korea put a line below the number.

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  Common minimum speed limit sign.

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  UAE and Saudi Arabia minimum speed sign.

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  Argentina minimum speed sign.

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  Canada (Quebec) minimum speed sign.

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  Chile minimum speed sign.

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  Colombia minimum speed sign.

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  Indonesia minimum speed sign.

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  Japan minimum speed sign.

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  Philippines minimum speed sign.

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  South Korea minimum speed sign.

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  United States minimum speed sign.

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  United States (showing both maximum and minimum speeds).

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  United States (metric minimum speed).

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  United States (metric, dual maximum and minimum speeds).

Special Speed Limits

Some speed limits apply only to certain types of vehicles or at certain times. These limits are usually lower for safety.

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  Australia - Speed limit only at certain times.

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  Australia - Speed limit for Road Trains.

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  New Zealand - Limited Speed Zone (max 100 km/h, but 50 km/h in bad conditions).

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  Romania - Speed limit for Trucks.

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  United States - Speed limit in a roadworks zone.

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  United States - Speed limit for Trucks.

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  United States - Speed limit for vehicles pulling trailers.

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  United States - Night time speed limit.

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  United States - Special sign for evacuation routes.

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  Safe speed sign in South Korea.

End of Speed Limit Signs

End of 30 km/h speed limit. The previous speed limit now applies.

Beyond this sign, the UK national speed limit applies (60 mph on open roads).

These signs show where a speed limit zone ends. After this sign, the normal speed limit for that area applies. For example, in the UK, it means the national speed limit (60 mph on open roads, 70 mph on motorways) now applies. In New Zealand, it means you are on an open road, but the 100 km/h legal maximum still applies. On roads without general limits, like the German Autobahn, it means there are no more specific speed limits.

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  Common "maximum speed limit" end sign.

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  Common "minimum speed limit" end sign.

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  Common "advisory speed limit" end sign.

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  Australia (now rare).

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  Australia.

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  Belgium, UK, Ireland, New Zealand, Singapore, Malaysia, and Switzerland.

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  Germany.

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  Japan.

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  Japan - Left arrow (Right arrow means "from here").

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  Philippines.

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  Philippines.

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  End speed limit 35 mph (United States).

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  End speed limit (United States, older style).

Advisory Speed Limits

Traffic signals showing a suggested speed limit.

Advisory speed limits suggest a safe speed for an area. They might warn you about the fastest safe speed for sharp curves.

In Germany, an advisory speed limit can be linked to a traffic signal. It suggests a speed to help drivers reach the next light when it's green, so they don't have to stop.

Technology and Speed Limits

Some cars in Europe have systems that help drivers follow speed limits. These are called intelligent speed adaptation (ISA). They help drivers keep to the limit in different areas. These systems make driving safer. About 25% of European car drivers think these systems are helpful.

In 2019, Google Maps added alerts for speed traps and cameras. This technology was first made by Waze.

Images for kids

• Graph:Chart

See also

In Spanish: Límites de velocidad para niños