Infrastructure at a Glance: Dutch Traffic Lights
US politicians often talk about the need to improve infrastructure, but what does that really look like?
The United States economy relies on a vast infrastructure network: from roads and bridges to rail and shipping ports, electrical grids, and fiber optic cables for internet access, the US maintains a lot of infrastructure. Despite the vital importance of infrastructure, it has been long neglected, leading to significant (and somehow still ongoing) incidents like Flint, Michigan’s contaminated drinking water system and decaying bridges spread throughout the country in desperate need of repair. In 2020, the American Society of Civil Engineers published an infrastructure report card that gave the United States a grade of C-, a slight improvement after two decades of Ds. While ambitious spending packages like the Biden Administration’s new infrastructure plan can help fix existing infrastructure, Americans and their politicians must think about how we transform and rebuild our infrastructure to suit our needs. While many people would initially think of repairing bridges, ports, roads, and decaying airports, part of the bigger picture includes an openness to new possibilities and areas that we do not associate with major infrastructure projects. Let’s discuss an everyday topic: traffic lights.
People think of traffic lights as simple machines: timed lights that let cars know when to go, slow down, and stop. This mindset has been created in America because traffic lights have been built and used incorrectly. When traffic lights are done properly, they are complicated and efficient mechanisms that change minute-by-minute depending on the circumstances at a given intersection. Let’s look at an example of America’s many “dumb” traffic lights and what a “smart” light looks like.
Here is the situation: you are leaving a concert at midnight, and there are no other cars on the road. As you approach your suburban town, you are met with a network of empty intersections accompanied by traffic lights. As you come to the first intersection, the light turns red, and with no other cars in the area, you are forced to wait 2-3 minutes for an entire cycle of lights that only you can see. Once you finally get through the first intersection, you can only hope that luck will prevail and all other lights will be green when you get to them (hint: they won’t). Although this example is simple, traffic lights that do not adapt to the traffic situation on the road slow cars, make crossing more dangerous for pedestrians, and discourage public transport. We have all seen a traffic light switch from green to red despite only one side having any cars, creating a backup leading to slow traffic. These “dumb” lights only switch according to an internal timer, regardless of external circumstances.
Now let’s head over to The Netherlands, where this type of situation doesn’t exist. Their traffic lights would detect only one oncoming car at our otherwise empty intersection and instantly change the car’s traffic signal to green, enabling the driver to pass through. Traffic lights in the Netherlands have many combinations and change depending on the traffic detected and where people are coming from. Most cities have detection circuits at low-traffic intersections to determine if there is a stopped car at a red light. Traffic-dependent detectors are missing from these intersections, which detect approaching traffic and change signals based on real-time traffic levels. These are used at the majority of intersections in Amsterdam.
While lights in America only prioritize cars, traffic lights in The Netherlands have two priorities:
1) Minimize conflict to reduce the number of times any road user will cross the path of any other for safety.
2) Optimize the movement of as many people as possible, not just as many cars as possible. This makes the road function much more efficiently.
Here’s how it works: In larger intersections like the one shown above, pedestrians may be given the green light to cross partway instead of waiting for the whole intersection to clear to start walking. This eliminates sprinting across a large intersection to “beat the clock,” as is often seen in America’s single-phase crossings. This also eliminates the dangerous nature of crossing an intersection while other cars are crossing through mechanisms like turning right on red.
The Netherlands heavily controls when cars can make right turns, increasing the safety for cars that are turning, pedestrians that are crossing, and allowing for more complex combinations of light signals. In this picture, cyclists are given a green light (arrow), while all cars are given a red light to allow them to cross. We can also see pedestrians (Orange highlight) are given a green light since they will not cross with the cyclists (Green highlight) making a left turn. This makes the intersection efficient (since two different groups can cross at once) and safe since no cars are allowed at the intersection. These intersections can adapt due to their advanced detection systems; they are so efficient that The Netherlands does not need a “right on red” policy, one that exists in the United States. This is good news for pedestrians as studies show major increases in crashes involving pedestrians/cyclists at intersections that allow right on red.
Remember, the second priority of The Netherlands traffic lights focuses on moving as many people safely through the intersection. When public transportation comes to an intersection (tram, bus, etc.), the light will quickly change to green for them. This makes public transportation more attractive as people often get to their destination faster than those using cars. It also just makes sense to prioritize a bus full of 40 people over a car with two people. The same principle is used for pedestrians that use the beg button for walking. These points demonstrate the mindset of civil engineers in America, where pedestrians, cyclists, and any other forms of transport are seen as a nuisance to cars rather than equals or superiors.
Dutch traffic lights are far more complicated than one can describe in 1,000 words, but these scenarios should give a good understanding of how desperately we need to change many pieces of infrastructure that are not often reviewed or discussed and instead overshadowed by structures like runways and bridges. I encourage everyone to think about what infrastructure you use in your everyday life, how it could be better, and what that would mean for you or someone you know. If you are interested in learning more, this video explains many of the scenarios I used here and more.
TLDR The United States has a thousands of “dumb” traffic lights in key areas. It is time to rethink our priorities for everyday transportation and update our systems for the 21st century.