Highways are designed to make traffic flow smooth & fast. But, when there are too many vehicles on the road, you may face a long delay. That’s why the ramp metering system is used to reduce congestion during rush hours.
In this article, we will tell you what is ramp metering and different types of ramp devices.
What is a Ramp Meter Device
A ramp meter device is a traffic control device that is used on your roads. This device has sensors that are placed on both on-ramp and road. Basically, these sensors collect information about the speed and volume of traffic. The ramp meter controller reads this data and decides the right time to change ramp signals.
Freeway Ramp Meter
You can mostly see these ramp meter devices on freeways. Basically, they control how many cars can enter a mainline. In other words, they do not allow all the vehicles to use the main road at the same time. Therefore, your ramp meter intelligently uses empty spaces to organize traffic.
How Ramp Meters Work: Ramp Metering System
Well, ramp metres also work like your normal traffic signals. But they are placed only on the freeway ramps that connect with main roads.
- First of all, sensors that are placed on roads count your car and check its speed.
- Basically, these sensors work with computers that study traffic data.
- When information is processed then it goes to the ramp meter controller.
- After that, your ramp controller decides when ramp lights will change colors.
- In case of multi-lane, It informs you about a specific number of vehicles that are allowed at a time.
- Moreover, they also make sure your cars join main roads with a safe speed limit.
Ramp Metering Signals
This is a ramp meter signal that works like normal traffic lights. The difference is that when it shows green light you can move toward highways or main roads. On the other hand, a red light tells you that this main road has a rush and you have to wait.
Multi-lane ramp meters inform you about alternative routes or lanes. For this purpose, they use green light with a directional arrow. This arrow guides you about the exact lane that is clear for you.
Ramp Metered When Flashing Sign
You can often see this sign board on freeways. This sign simply tells you that your vehicle and its speed is tracked. At that time, you have to slow down your car and look at flashing lights.
If we talk about its appearance, it is a diamond shaped sign board with a yellow background. There are clear black words on it that say you “Ramp Metered When Flashing”.
How to Install Ramp Meter
- If you want to install a ramp meter then you must collect all previous information of that route. Your information should be about its traffic flow and volume.
- When you have collected all needed data, process it deeply.
- After that, decide the type and number of ramp meters that you want to install on roads.
- Next step is the selection of a location that has enough space to hold a queue of vehicles.
- Prepare a short zone where your one lane turns into two lanes.
- Once your location is specified then place hardware for example; traffic signal, controller cabinet and vehicle detector.
- After the placement, link all hardware devices with wires. You must connect them with the ITS network to access them from a remote location.
- After complete installation of your ramp meter test it. Actually, it is important to ensure that all connections are working.
Types of ramp devices
Single-Lane Metering / One Car Per Green
As its name shows, it is a type of ramp metering where one vehicle is allowed to enter on a freeway. You can see these ramp metres on roads that handle approximately 900 vehicles per hour.
This thing keeps a freeway secure and reduces traffic jams. Usually, you can see these ramps where traffic demand is moderate. And a single lane can handle the volume of that road.
Multi-Lane Metering
If you see a ramp near your main road that has more than one lane, well it is a multi-lane ramp. This ramp has a more complex system than a single one. There are more than one signal heads that are installed according to the number of lanes.
These all lanes are controlled according to traffic flow of the main road. In addition, these all signals are connected with one another.
Fixed Ramp Metering
You can observe fixed ramp metres in some areas. Actually, they use predefined algorithms to control rush on highways. For example; it lets vehicles go one by one after each 5 seconds even in off-peak hours.
Variable Ramp Metering
To solve this problem of pre-set or fixed timings, variable ramps come into markets. Well, they use real time data of main roads. Therefore, they stop you when the main road is congested or traffic is slow. Moreover, variable ramp meters automatically change the time to enter highways.
Ramp Meter Rules
When you see a “Ramp Meter Ahead” sign, you have to follow some rules and regulations. Some of these are;
- You can see a white line near a ramp meter. Basically, this is a stop line where you have to put brakes on at a red light.
- In case when you move toward the main road even in red light you can be fined.
- Look at the signal head and wait for the green light.
- Stay in your lane and follow markings that are placed on sides.
- When the light turns green only one vehicle is allowed to join that main road. So, wait for your turn in the line.
- When you are on a multi-lane ramp then one vehicle from each lane is allowed to move forward.
- Keep your focus on the signal, it will cycle again to allow you.
- You can use an acceleration lane which is created to match the speed on highways. In this way you can avoid accidents.
- When you pass the ramp meter then do not stop on a shoulder of the road.
- If you drive a bus or carpool then you must stop on HOV bypass lanes. Actually, these are designed for high occupancy vehicles. In addition, they can bypass the other signals.
Safety Benefits of Ramp Meters
- Many studies show that ramp metering can reduce 20to 50% roadcrashes on certain freeways.
- Ramp meters avoid cars to join a main road at the same time. Which can reduce the number of collisions. Typically, ramp meters
- Provides you a safe space to drive on main roads.
- When you are on a main road you get time to react and avoid confusion.
- Organize flow of traffic and create a safe environment.
- When you stop on a ramp you can accelerate your vehicle to balance the speed with highways.
Technological Challenges of Ramp Metering
- Sometimes, road sensors do not work in the right way. In such a scenario, accidents ratio can be increased.
- There are many different hardware and software devices that have to work together in a ramp meter. That’s why it is very hard to manage.
- As you know, they use real time data and slow networks can affect it.
- There are too many tools used in your ramp meters, therefore maintenance cost is very high.
- Variable ramp metering has advanced algorithms that are difficult to adjust.
- It is an expensive option for you.
- This Complex system needs updates on time to make it compatible.
Final Words
So, ramp metering is an excellent way to control traffic with the help of technology. You must follow rules of ramp metering and its installation standards. If you are looking for advanced traffic management solutions & road safety products, you can contact our team now.
FAQs
Do Ramp Meters have Cameras?
Yes, many ramp meters have CCTV cameras. But you can’t always find them.
Can You be Ticketed at a Metered Ramp?
Yes, you can be ticketed at a metered ramp if you break certain traffic rules.
How Do You Know If a Ramp is Metered?
You can guess it from specific signs, signals and lights for example; “Ramp Device Ahead”.
Who installs Ramp Meters?
Well, Ramp meters are usually installed by government transportation agencies.
