Why are traffic lights so expensive?

Learn more about how traffic signals operate, and how and when they are installed.

Traffic signals are a vital tool used to manage traffic interactions at an intersection. For the most efficient operations, a traffic signal system must be monitored and adjusted periodically to serve changing traffic patterns.

A properly optimized traffic signal system has multiple goals:

• Reducing delay for all users.
• Improving safety.
• Reducing air pollution and use of fossil fuels (less time idling).

Traffic signal timing

Traffic signal timing is managed by a special computer called a traffic signal controller. This controller is programmed with the time needed for each signal phase (green and walk times) and clearance times (red, yellow, and don't walk times). Optimum timing is when all users are subjected to the least amount of delay possible. With the different volumes and modes of travel moving through a signalized intersection, this can be particularly difficult to achieve.

At an existing system, traffic engineers collect data including traffic patterns, speeds, and volumes. This data is analyzed and models are generated so that timing plans can be updated and implemented that fit the current conditions.

Vehicle signal times

For vehicles, green times are normally set to allow the greatest amount of traffic through, with the least amount of delay for other conflicting directions of travel. Yellow times are set in an effort to allow drivers enough time to stop safely at the onset of yellow. Red times are set to allow the intersection to fully clear before a new direction of travel enters the intersection.

Pedestrian signal times

Pedestrian walk times are set similar to vehicle green times. Pedestrian clearance (flashing "don't walk") are normally set based on walking speed, as described in MUTCD Section 4E.06. Wider crossings result in longer pedestrian clearance times. The timing of the "don't walk" has a minimum required before conflicting vehicle traffic may be released, and is also described in MUTCD Section 4E.06.

Overall cycle time

The overall cycle time, or cycle length, for a traffic signal system is the time it takes from the start of green for one direction until the next start of green for that same direction. The cycle length has to include all of the green, yellow, red, walk, flashing don't walk, and don't walk times for every direction served, although some of these overlap (such as opposing through traffic). Rarely is the cycle length longer than 120 seconds (2 minutes), and most traffic engineers strive to keep the cycle length as short as possible. If there is no traffic on a cross street, a signal system may "rest" in green for the major roadway, where the signal "pauses" in the middle of the cycle.

Coordinated signal systems

When multiple traffic signals are close together on a highway, they are normally interconnected and are often operated as a coordinated system. Coordinated Signal Systems are probably the most misunderstood signal system networks. A coordinated signal system network does not mean that a driver on the main roadway will get green lights all the way through the network. But the system is set up to get drivers through the entire network as quickly as possible.

There are times and locations where this can mean sequential green lights through the whole system, but that is not always the case. Traffic volumes, distances between traffic signals, sizes of intersections, pedestrian activity, and other factors may not allow for truly sequential green lights.

Many coordinated signal systems are not operated in coordination all the time, but instead only during peak commute hours. This is why networked systems may operate differently depending on the time of day, which may mean more or fewer stops for users.

Coordinated systems can also cause more headaches for side road users. Coordinated signal timing is typically based on the largest and most complex intersection in the network. This can result in longer than needed times at smaller intersections. If you find yourself waiting at a side street with little or no conflicting traffic, and it's in a coordinated system, this may be why. However, as with general cycle length, coordinated systems are normally set up so that no system in the network has a cycle length greater than 240 seconds (4 minutes), and are as short as possible.

Accessible pedestrian signals

Accessible Pedestrian Signals (APS) are traffic signal system devices which combine a pedestrian detector – commonly a pushbutton – with pedestrian signal indications in non-visual formats. These non-visual indications are both audible and tactile.

APS speech messages

We require that all APS units used in WSDOT owned and operated traffic signals include speech messages, even if they may not be used at an intersection. In order to provide a consistent message throughout the state, speech messages must follow the APS Sample Message Table (PDF 456KB). We also require that all APS units at an intersection operate in the same way, where all use speech messages or all use the "rapid tick" indications.

Installing a traffic signal

Installation of a traffic signal requires a significant amount of investigation and evaluation. Traffic signals are used to solve specific traffic problems, and may potentially cause new ones - particularly when installed in inappropriate locations. Traffic signals are generally most beneficial when trying to provide breaks in major roadway traffic for crossing movements. To be truly effective, any traffic control device must be perceived as reasonable by users.

Evaluation

Most states follow the MUTCD Warrant System (MUTCD Section 4C) to determine if a traffic signal should even be considered at an intersection. To make these evaluations, traffic data including volumes, speeds, and collision data is collected and analyzed. In some cases, a lesser form of control, such as stop or yield signs, may be tried and proven ineffective before a signal is considered.

Angle collisions, such as "T-bone" type collisions, and pedestrian collisions are common factors for installing a traffic signal. Traffic signals can reduce these types of collisions, but rear-end collisions typically increase after a traffic signal is installed. The trade-off is that these rear-end collisions generally are less severe than the higher-speed angle collisions.

Installation of a traffic signal at an inappropriate location may also have the unintended consequence of diverting drivers to alternate routes. These alternate routes may not be designed for increased or faster traffic, such as residential neighborhoods where drivers may not abide by lower speed limits, putting residents and others in greater danger.

As part of evaluating an intersection for a traffic signal, we will normally consider other possible control alternatives, such as roundabouts <need new link>. We make an effort to apply the most appropriate solution to intersection management, in order to keep traffic moving safely and smoothly.

Cost

Traffic signals are expensive systems. A typical basic traffic signal system will cost around $250,000 just for the signal system installation. If this is the entire construction project, this cost will be closer to $500,000 or more, as things like engineering, work zone traffic control, and supporting construction work is included in the project. Traffic signal systems also have ongoing power bills and maintenance costs for technicians and engineers to keep the system operating safely and effectively, which is roughly $8,000 per year. That works out to an additional $200,000 to keep a signal system operating for 25 years.

Requesting a traffic signal

If you think a traffic signal is needed at an intersection, contact the agency that manages the intersection and they can discuss the location with you.

For intersections on state highways, even inside cities, contact WSDOT. If the intersection is in an area where the state highway signals are managed by a city, we will get you to the appropriate agency.

For other intersections, contact the City Public Works Department for intersections within city limits, and the County Public Works Department for intersections outside city limits. You can also discuss with them other possible improvements to the intersection which may be enough to resolve your particular concern.

With so many traffic lights efficiently operating around us, it’s natural to wonder how much does a traffic light cost. Traffic lights are complicated to install and tough to maintain. That’s why they are a lot more expensive than they seem.

Also, the expense does not end with installation and maintenance. You will be surprised to know about the additional costs that come with the public traffic light system.

How Much Does A Traffic Light Cost?

Traffic light costs can vary, depending on the situation. The cost of installing a private traffic light will be nowhere near the cost of the public traffic system. So, let’s see the difference between these two.

Individual Usage

If you want to get a traffic system privately, the cost will start somewhere around $90 and can rise up to $300. One thing you need to understand about these traffic light systems is that they’re not anything like the ones you see on the roads. That’s why you can get them within this price range.

The amount isn’t fixed because it depends on where you are buying the traffic light from. Different sellers will demand a different price range, so the cost will vary.

As I have mentioned before, the lights you can get in this price range are not similar to the ones you see on the roads. Some of them may look like them, but the functionality is entirely different. These won’t be able to run on a timer either.

Public Traffic Lights

If you want to calculate the cost of traffic light systems set up by the government, the equation will get a bit complicated. Let me demonstrate it part by part.

First of all, we need to answer the question of how much does a traffic light costs to install. For the installation of a traffic light system, the cost can vary from $80,000 up to $500,000. The vast difference is based on how complex the system is and where the traffic light is going to be.

Another cost that needs to be added to this equation is the cost of maintaining these lights. The government pays around $5,000 to $10,000 per year for maintaining traffic light systems.

So, how much does a traffic light cost to replace? Calculating traffic light replacement cost means considering an entire construction. The average cost of an entire construction of traffic lights can be around $500,000.

Additional Expenses

Is there any additional traffic signal cost? One cost to consider is the electricity bill. The bill per traffic light can be around $1500 per year. Other than the maintenance cost that I have already mentioned, there can also be another cost for upgrading the system.

The maintenance cost can be roughly around $8000. This cost allows the signal system to operate smoothly and effectively.

To keep the traffic lights running and functional, there can be an annual cost of $3000 to $10,000 per year. This cost occurs when the government upgrades the traffic lights.

Related: Street Light Cost

Factors Influencing The Traffic Light Cost

As you can see, the cost is in a range. That means the price can be anywhere between that range. So, why this versatility? Let’s take a look at some factors that can affect the cost of traffic lights.

Type Of Traffic Light

Initially, we have to separate personal usage and public traffic lights because these two aren’t comparable. So, if you’re installing a traffic light for your own use, the cost will be a lot less.

On the contrary, public traffic light systems are a lot more expensive and come with a high maintenance cost too. Considering the installation, maintenance, and up-gradation of the public traffic system, it can be summed up to be a large amount.

The hardware and the technology required for installing the system are what cause a traffic light to be so expensive.

Type Of Modification

The cost for installing new traffic lights and replacing them will not cost the same. Besides, sometimes the system doesn’t require reconstructing the whole thing. So, the type of installation can also have an impact on determining the cost of a traffic light.

Place Of Installation

The price can also vary depending on the place. One area can require a higher price to install a traffic system compared to another area. This usually happens depending on the roads and the complexity. For instance, a basic system will not be as expensive as a four-way crossway.

Complexity Of The Installation

A complex traffic system installation will cost a lot compared to a simple traffic system. So, one factor affecting the cost of a traffic light is the complexity of the system.

Frequently Asked Questions

Q. How expensive is a traffic light?

Traffic lights for personal use are not expensive like the public ones. You can get a traffic light system for between $90 and $300 for your own use. However, the public traffic lights are a lot more expensive.

Q. Why are traffic signals so expensive?

The hardware required for traffic signals is very expensive. Besides, modern traffic systems are monitored and operated by computers, which come pretty expensive too. That’s why installing this complex system is expensive.

Q. Do all traffic lights have sensors?

Not all traffic lights have sensors. Some lights have timers instead of a sensor that allow them to operate smoothly.

Q. How often are stop lights replaced?

Even though stop lights are scheduled to be replaced each six to seven years, sometimes this period can get extended to ten years.

Q. Are roundabouts cheaper than traffic lights?

Roundabouts are cheaper to install and maintain compared to traffic lights. Even though suitability depends on the situation, roundabouts certainly cost less.

Final Verdict

As you can see, how much does a traffic light costs can be different depending on certain factors. You can either request a traffic system in your area through the authority or install one if it’s for personal use.

If you are considering a personal traffic light to install near your house, the cost won’t be much. You can bear the cost alone. However, the price of a traffic light may vary, depending on where you are buying it from.

Hello, I’m Michael Rosales an expert in cars. As a little boy, I have always loved cars. Over the years I became lucky to have the opportunity to work as a car dealer. It was at this stage I became vast in the knowledge of cars, things you need to know when buying cars and how to minimize cost while still getting your dream car.