Traffic Lights: What are they good for?
Understanding the Purpose of Traffic Lights: A Lesson from Chesterton's Fence
Imagine walking through a field coming across a fence standing alone, seemingly blocking nothing.
One might think, "This fence is pointless, let’s tear it down."
But before making any changes, consider G.K. Chesterton’s wise principle commonly known as Chesterson’s Fence.
It goes more or less as so: "If you don’t see the use of it, I certainly won’t let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it."
In other words, one should understand why something was placed there in the first place prior to demanding a change or reversal. This is something that’s strangely difficult for anointed activists.
But the lesson behind Chesterson’s Fence can be applied to “debates” about traffic lights especially when cyclists are involved.
Traffic lights are seen as a bugaboo for many cyclists and motorists alike.
Cyclists are often accused of running red lights, a claim which is often true.
There are a few reasons bicyclist do this, however, so let’s take a quick detour.
Traditionally, bicyclists are legally granted the same rights and duties as drivers of vehicles which includes the duty to obey traffic control devices such as traffic lights. However some jurisdictions have changed the traffic law to allow bicyclists in certain cases to legally behave differently at traffic lights (covered in The Red Light and Stop Sign Cake) under an oversold guise that the activity is safer and reduces collisions.
Another reason bicyclists may run traffic lights because they attempted to stop for them in the past and the lights never changed. In other words their bicycles are not detected for some reason. This can be frustrating in time of low traffic (the author here has sat for several cycles waiting for green turn arrows, often early in the morning or late at night when motor traffic is low).
But often missing from the highfaluting “bicycle activists” are practical lessons for bicyclists on how to identify where induction loops are and how to trigger them or tricks such as how to take advantage of traffic signal timing. (see John Allen’s “All to Myself, Thanks to Traffic-Signal Timing”) Unless one bikes in an area with no traffic lights or at traffic light controlled intersections with video sensors or certain types of detector loops, a bicyclist is likely going to someday encounter a traffic signal that doesn’t detect them. Hell, bicyclists who are permanent edge riders will likely never get close enough to any detection loops.
With all this silliness as background noise, some “bike activists” argue something akin to, "Traffic lights are for cars. Bicyclists and pedestrians shouldn’t have to obey them."
Here are a few examples:
Stop lights are for cars. If everybody was on bikes we wouldn’t need them.
And:
Traffic lights are car infrastructure, bikes don't need them...
If these two activists were coming up towards the fence in the Chesterton’s Fence parable demanding with little to no question to remove the fence.
Traffic engineer and legitimate cycling advocate Bob Shanteau who is co-author of "The Marginalization of Bicyclists," wrote of this issue of traffic lights on a cycling message board.
I recall that when I gave a presentation on bicycle detection at a meeting of the Transportation Agency for Monterey County's Bicycle Advisory Committee some years ago, several people, including the representative from Velo Club Monterey, dismissed my work by saying they didn't stop at red lights. I got much the same response at a booth demonstrating how loop detection works during the Sea Otter Classic the same year as well as to the article that Dan Gutierrez and I wrote on the car lane paradigm some years later. That's when I realized that bicyclists in general and bicycle advocates in particular are simply not interested in what I have learned in 50 years of bicycle traffic engineering. Bicyclists want the "freedom" to ignore traffic laws, stay out of the way of cars and not to interact with motorists as drivers. And enforcement officers and traffic engineers are happy to oblige them.
These first two perspectives arise from a zealous frustration with current traffic systems, often because the people expressing these frustrations don’t understand the rules of the road themselves which is a common issue with many “bicycling activists.” But these perspectives, dripping in utopian and elitist anti-car luxury belief nonsense overlooks the broader history and purpose of traffic lights. Shanteau correctly points out a schism inside the greater umbrella of bicyclists with some who wish to learn to figure out how the system works and others who don’t and remain anti-social/ClusterB(ike) activists.
While it is true that the majority of traffic at an intersection with traffic lights is likely to be various types of motor vehicles be they cars, trucks, motorcycles, etc., traffic lights were not invented for them. They were instead invented for all the road users.
"Before automobiles even swarmed over the roads and streets, there was a need to control traffic to avoid accidents and keep vehicles moving smoothly," writes Larry Clark in the article “Traffic signals: A brief history.”
This was back when the typical street scene looked like this:
The first known traffic signal was installed in 1868 in London, long before automobiles were common and back when most traffic consisted of animal-driven carriages, pedestrians, later towards the end of the century floods of bicyclists. These busy intersections were either completely uncontrolled or had someone akin to a traffic cop using hand signals, flags, or semaphore. This signal was intended to manage the flow of horse-drawn carriages and pedestrians, ensuring predictability and safety for different road users.
As cities grew and traffic became more complex, the need for a system to regulate all types of road users became evident requiring the demand for a set of rules of vehicle operators and pedestrians as William Phillips-Eno envisioned in the late 1800s in NYC. Eno’s rules became the backbone for virtually all modern traffic law pertaining to drivers of vehicles (which includes bicyclists) and pedestrians. Eno’s system initially used signage such as the ancestors to modern stop and yield signs as opposed to traffic lights but the rules of movement remain the same. (There’s a plethora of Chesterson’s Fence parable applications in this landscape as well)
It wasn’t until 1912 when the first electronic traffic light was installed at an intersection in Cleveland with the intent of controlling that city’s growing motor vehicle traffic and then in 1917 when the first system of traffic lights was installed in Salt Lake City. Pedestrian push buttons arrived in the late 1920s providing a dedicated signal phase at these intersections for people walking although there is some controversy here. (Prior to push buttons, a pedestrian could walk on a green light.)
Traffic lights serve a crucial role in maintaining order and safety at intersections such as:
To Prevent Collisions: By clearly designating when it is safe to move and when to stop, traffic lights reduce the likelihood of collisions between vehicles, bicycles, and pedestrians.
To Organize Traffic Flow: They ensure that all users, regardless of their mode of transport, have a fair opportunity to navigate intersections. Proper phasing of the lights at intersections enables different users to turn, cross, or otherwise move safely and efficiently without the risk of colliding with others in sufficient time. (Intersections, as discussed in other articles are about destination positioning as opposed to speed positioning.)
To Enhance Pedestrian Safety: Pedestrians are not drivers of vehicles but they are lawful road users. Pedestrian signals at traffic lights provide safe crossing opportunities, minimizing the risk of accidents provided drivers of vehicles and pedestrians both obey them.1
Chesterton’s Fence teaches to understand the reason behind an existing rule before changing it. In the case of traffic lights, like the seemingly unnecessary fence, they have a purpose grounded in historical need and practical safety. Dismantling the expectation that cyclists and pedestrians should obey traffic signals without understanding this could lead to chaos, increased chances of collisions, and an overall feeling that the roads are more dangerous for cycling than they really are.
That’s not to say traditional signalized intersections are without their issues, aside from the cycling-related ones mentioned earlier. Pedestrians often complain of motorists not obeying their right of way at intersections when they have the legal right of way. Oftentimes this stems from motorists making unlawful right turns on red failing to yield to pedestrians. Furthermore, collisions between motor vehicles and other users can be severe, especially at high speeds.
In developing countries, where “traffic violence” is likely actually something akin to an “epidemic,” things can be utterly fast and chaotic at intersections with rules that appear to be more “might makes right,” than a turn-based, first-served, rules'-based system discussed here.
Alternatives exist to the traditional signalized intersection: traffic circles, rotaries, and roundabouts. Depending on where one is regionally, some or all these terms mean something slightly different but the principles remain the same.
They come with their own sets of benefits - often drivers (including cyclists who choose to use them as drivers) don’t have to come to a complete stop or if they do are not stopped for as long as they would in a signalized intersection. Crashes are often less severe and impact points, at least if one’s in a motor vehicle, are not head on or “t-bone.” It could be argued too that circular intersections reduce wear and tear on motor vehicles and can increase fuel efficiency, not to mention they can look pretty with landscaping and ornamentation. John Allen notes some disadvantages in an article including ignorance on how to use them and a lack of drivers yielding to pedestrians. Apparently their designers, traffic engineers, aren’t even all on the same page on how to use them correctly too and there are serious issues with visually impaired pedestrians using them. Even in the Netherlands, the ballyhooed Holy Land for many “bicycle advocates” getting ones to “work” properly has been a bit of trial and error, especially with the added complication of “protected” bike paths adjacent to roads.
For those who want to argue against traffic lights, fine, go for it.
But keep in mind the actual reasons they were invented, what problems they attempt to solve, their tradeoffs before simply asserting they need to be abolished because of the false notion they were invented for cars.
And try to see if you can get through this on a bicycle or on foot.
This gets controversial among anti-car activists who often assert that the public roads are less friendly to pedestrians and have become car-centric and sometimes they do have a point. One of the criticisms is motorists turning right on red not yielding to pedestrians when it’s the pedestrians who have the “walk” sign. Another is a far distance between legal crosswalks which encourages many pedestrians to cross unlawfully outside these areas instead of walking the extra distance to use the formal crossings.