| Anyone who has ever driven a car is familiar with traffic intersections. A traffic intersection is a place on the road where vehicles have an opportunity to change direction as opposed to continuing forward. They are the regulators of the automotive world making sure vehicles coming from different directions pass safely. In most American cities, the main component of an intersection is the traffic light. The traffic light was invented by Lester Wire who in 1914 installed the first electric traffic light in Cleveland, Ohio as he was concerned about the rapid increase of automobiles on the road following the industrialization period [1]. Traffic lights display colors (green for go, yellow to slow down, red to stop) which instruct a driver on how to behave as they are approaching an intersection. Most of the time traffic lights work as intended. The rest of the time, they are inefficient. In this human use analysis, the experience of traffic lights will be evaluated. |
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What's the experience of using a traffic light?
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Step 1: Drive on a road. |
Step 2: Notice traffic light turning from green to yellow to red. You stop. |
Step 3: Notice there are no other cars passing through the intersection. |
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Step 4: Continue to wait at light. |
Step 5: Light finally turns from red to green. |
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What do traffic lights do well?
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Better than having no traffic lights at all, otherwise the roads would turn into chaos.
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It allows pedestrians to cross the street.
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It is fair, even if inefficient at times.
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Side note on rotaries: Rotaries interestingly don't have traffic lights as the default is to drive through unless prior vehicles are already in the rotary in which case they are given priority. However, most American cities have square intersections and would require a change in the existing infrastructure (i.e. removing sharp intersection corners and adding a mound in the center with some islands to separate lanes) to accommodate rotaries. Sometimes these changes are not feasible due to the layout of a particular intersection, which is why playing around with existing traffic lights could be a potential solution.
What do traffic lights do poorly and how can we solve it?
It is estimated that the average person spends 38 hours in traffic every year [2]. According to a Paychex survey, 41% of participants listed commute as one of the reasons they changed jobs [3]. Current electric traffic lights haven't changed much since when they were first invented in 1914. Yet a lot has changed in the automotive landscape. We have more volume of cars, we have larger vehicles, and we have distracted drivers. People want something different. What if the seemingly humble traffic light can be upgraded into the 21st century?
Problem 1: When there are too few cars, cars stop needlessly when it is perfectly fine to go ahead.
For the scenario showing the steps of the traffic light experience, a driver is cruising but then has to stop at the light only because it says so and not because there are cars on the perpendicular street waiting to go. After the pre-determined cycle time, the light then turns green, causing the driver to accelerate. The decelerating and accelerating of the car is bad for the fuel economy, which is another incentive to let cars just continue on. There is a need for traffic lights which are adaptive to their environment.
Imagine instead that the driver is cruising and because there are no cars being sensed on the perpendicular street waiting, the driver is allowed to go through the intersection. This can be done with every car having a chip installed. Smart traffic lights would sense this chip and develop a real-time map of approaching traffic. The smart traffic light can tell how many oncoming cars are approaching. If there are many cars approaching, then the light stays green. If it senses that there are too few cars approaching from one direction as compared to the cars waiting on the perpendicular street, then it can decide to prioritize the street that has more cars waiting. At the same time, this smart traffic light can have a sensor on the back to determine if there is a buildup of vehicles ahead. If this is the case, then the smart traffic light would then turn red until proper flux has been achieved. These smart traffic lights can communicate with each other.
Problem 2: When there are too many cars, intersection blockage happens.
I've witnessed countless numbers of vehicles who force their way through an intersection and end up blocking it due to backup ahead. This then prevents the vehicles from the perpendicular street from advancing. And yet I've never witnessed a police officer issue a ticket even though there are "Do Not Block Intersection, $150 fine" signs posted. Currently, there are no good enforcement strategies and after a time, drivers end up becoming desensitized to the sign like I have, knowing there will be no consequences.
Take a look at this intersection. Notice the car circled in blue is trying to turn but can't due to the cars circled in red blocking the intersection (you can see a big X in the middle of the intersection signifying not to block it). The cars blocking the intersection can't move unless the light ahead turns green. In this image, Traffic Lights 1 isn't aware that Traffic Lights 2 is still red. If it were aware, then it would itself turn red seeing as no more cars can pass through. From observation, when Traffic Lights 1 is still green, it gives drivers a sense of entitlement that they should be advancing ahead even though they risk blocking the intersection all for the sake of making the light. They feel possessive of their "right-of-passage" so to speak. So, if Traffic Lights 1 turned red, it eases the anxiety of some drivers that they need to obey the color lest they anger the cars behind them because have decided to do the right thing and not block the intersection. The smart traffic light can issue tickets to vehicles that block intersections if it prevents cars from the perpendicular street from advancing when it is their turn. This will discourage drivers from doing this in the first place and help prevent blockages.
In fact, if you've been driving on the highway recently, you will notice that traditional toll booths have been replaced by overhead lights and cameras. No longer will cars have to go from 60 mph to 5 mph to pay their toll in cash or go slow enough for the EZ-Pass reader to register. From my personal experience, this has greatly alleviated the congestion that occurs on the highway. How do drivers pay their toll then you ask? Well with this new system, drivers who don't have an EZ-Pass will just be sent a bill later to their home address, as the cameras take photos of their license plates so can track down the driver. While we dont normally have to pay tolls while driving in the city, a similar system can be implemented on local streets. The technology exists to monitor.
References
[1] https://www.ibtimes.co.uk/history-traffic-lights-100th-anniversary-first-electric-traffic-system-1459680
[2] https://www.theatlantic.com/business/archive/2013/02/the-american-commuter-spends-38-hours-a-year-stuck-in-traffic/272905/
[3] https://www.inc.com/peter-economy/15-reasons-why-people-quit-their-jobs-and-what-you-can-do-about-it.html