Speed Limits: History, Types & Speed Limit by State

Depending on your driving personality, you may love speed limits or not, but no matter what, they're everywhere and an important part of safe driving. Because speed limits are posted on signs on just about every street and interstate highway around the country, we’re dedicating time to look at them closely. How did we get speed limits? Why do they vary so much on highways from state-to-state? Have they changed over the years? Keep reading to learn all of this and more!

History of Speed Limits

According to the American Safety Council, speed limits date all the way back to 1901 when Connecticut set a maximum speed for motor vehicles. The results of the legislation? Drivers were limited to 12 miles per hour inside city limits and 15 miles per hour on rural roads. As the years passed, cars were able to move at higher speeds, and speed limits were adjusted to match scientific advancements. Today, speed limits are in every state, and they continue to evolve as both vehicles and roads become safer.

How are Speed Limits Established?

Wondering how speed limits are set?  You’re not alone! The numbers you are used to seeing are actually the result of in-depth studies conducted by state and local transportation agencies. These studies consider a number of factors, including, but not limited to:

• Roadway type and setting
• Visibility
• Roadway features, like curves and hills
• Crash history on the road
• Pedestrian and cyclist traffic
• Lane and shoulder width

By weighing all of these factors and many more, experts are able to determine how fast people can drive while remaining safe.

Different Types of Speed Limits

When it comes to speed limits, most drivers believe they just have to stay under the indicated number, and they’ll be okay. However, speed limit laws are more than that, as noted here by the Federal Highway Administration. Speed limits set the legal maximum and legal minimum speed at which vehicles may travel on a given stretch of road. Let’s take a look at different types of speed limits.

Statutory Speed Limits vs Posted Speed Limits

Oftentimes, state legislatures have set speed limits for different types of roads. Lawmakers might determine that all interstates should generally have a speed limit of 70 miles per hour that drops to 60 miles per hour around large cities. These numbers, statutory speed limits, act as a starting point or base, and they can be enforced even if there’s no posted number along the road.

Meanwhile, posted speed limits are exactly what they sound like. These are the bold, black numbers you see painted on the white, rectangular signs on the side of a road. A posted speed limit might be the same as a statutory speed limit, but it could also vary. If a particularly curvy stretch of remote highway is deemed to be dangerous, it might have a lower speed limit than other rural highways around the state.

Basic Speed Limits vs Absolute Speed Limits

Anyone who has driven a car has seen a speed limit sign, and it’s a pretty simple concept to understand. If you drive over the number posted, you’re in danger of receiving a speeding ticket. However, this is just one type of speed limit, known as an absolute speed limit. In other words, that is the absolute fastest you can legally drive on that particular roadway.

Another type of speed limit law that many people are unaware of is a basic speed limit, which is situational depending on driving conditions. If you look at your state’s laws, you might find something along the lines of this California statute:

“No person shall drive a vehicle upon a highway at a speed greater than is reasonable or prudent having due regard for weather, visibility, the traffic on, and the surface and width of, the highway, and in no event at a speed which endangers the safety of persons or property.”

As you can probably tell from the description above, basic speed laws exist to protect people as driving conditions change. For example, if you’re driving 70 miles per hour (the posted limit) on a crowded interstate in the middle of a snowstorm, that could be considered unsafe given the circumstances.

You might also have heard of a presumed speed limit. If you drive over a presumed speed limit, you have the chance to make the case that the speed you were driving was actually safe considering the circumstance (like a lack of traffic and good visibility). However, this leaves a lot to chance and can be risky because you can’t assume you’ll beat the presumption that you were speeding.

Minimum Speed Limits

Pretty much every driver is aware that they can’t drive above a certain speed without risking an expensive traffic ticket. But did you know that you might not be allowed to drive under a certain speed? Minimum speed limits also exist to make sure drivers stay safe, but in this case, it’s to keep people from driving slower than expected. Why is driving slow a bad idea? Wouldn’t that mean the driver is being careful? Not necessarily. If weather conditions are perfect and visibility is clear, driving 35 miles per hour on an uncrowded interstate would be an unexpected safety hazard for other cars. You can also find yourself in trouble if you’re driving too slow in the left lane, which is why you might see signs telling slower traffic to keep to the right.

Other Types of Speed Limits

According to the Federal Highway Administration, some speed limits are determined on a conditional basis. For example, school zones and construction zones have special speed limits to protect drivers, pedestrians, and workers. Also, some roadways feature variable speed limit signs that can change depending on factors like weather. Finally, advisory speed limits are seen on specific parts of a roadway, like large curves.

Recapping Different Types of Speed Limits

In summary, speed limits are designed to keep us safe and there a number of different kinds:

• Statutory speed limits are general guidelines for certain types of roads while posted speed limits are the actual numbers you see on signs.
• Absolute speed limits are the numbers posted on signs indicating the maximum speed you can drive, whereas basic speed limits are situational depending on driving conditions.
• Minimum speed limits exist so that people don’t drive too slow and put faster-moving vehicles in danger.
• Conditional speed limits are used in certain areas, like construction zones or school zones.
• Variable speed limits change depending on traffic and conditions.
• Advisory speed limits give drivers guidance in potentially hazardous stretches of road, like large curves or those with a lot of wildlife.

Do Speed Limits Vary from State to State?

If you’ve been driving for a while, you’re probably accustomed to seeing speed limits fluctuate from state to state. Without changing roads, you may be able to speed up or be forced to slow down when you cross a state line. Has this always been the case? Why do speeds fluctuate so much?

Has it always been this way?

Throughout U.S. history, states have been responsible for setting their speed limits. However, this changed in the 1970s when Richard Nixon signed a bill into law that made the national speed limit 55 miles per hour. Fuel had become more expensive due to conflict in the Middle East, and Nixon hoped this measure would force people to drive at a more fuel-efficient speed. National speed limit laws lasted for about 20 years with Congress returning speed limit decisions to individual states in 1995.

Why do speed limits vary in different states?

Lawmakers in one state may view 80 miles per hour as a reasonable speed, but lawmakers in a neighboring state might see 70 miles per hour as more reasonable. There are a number of reasons why different conclusions are drawn, but ultimately it comes down to safety. Every state’s officials have to determine what they believe is safe for their residents, and due to different factors (like geography), limits vary. For example, a rural highway in West Texas probably has less traffic and offers more visibility than what’s considered a rural highway in many other states. So a safe speed in West Texas might be higher than what’s regarded as a safe speed in a neighboring state.

Speed Limit by State

Wondering how fast you can drive in your state? We’ve got you covered! This is how fast you can drive on different types of roads in each state, according to the Governors Highway Safety Association. While these are all general guidelines, please note there may be exceptions. Always check every road for posted speed limits!

No matter what the speed limit is where you plan to drive, you’re going to need car insurance you can count on, so why not choose Direct Auto? Give us a call, visit us online, or stop by one of our locations for a free quote!