esign is all around us. It could be a doorknob, food menu, a photo-sharing application on your phone, or even an educational system. In most U.S. cities, due to urban sprawl, short-term city planning and lack of well-connected public transportation. Tens of millions of people need to drive to do their daily activities. Every day, most of us will stop at the interaction and look at traffic lights.
Electric traffic lights were first installed in the United States around the 1890s but more than a century later, its design remains stagnant. The ambiguous yellow light always makes me question whether I should prepare to stop or go through? According to law, every driver has to stop unless she is too close to the intersection to stop safely. So how do you define “too close”? 5 seconds? 3 seconds? The duration of yellow light varies from city to city and also varies according to the posted speed limit. It can be very confusing!
First, I start with research and learn that red-green color blindness (color vision deficiency) affects approximately 1 in 12 men (8%) and 1 in 200 women in the world. That is hundreds of millions of people! Let’s consider accessibility from the beginning of design, and think about how design can impact users with certain disabilities.
I am not a civil engineer, but I’d like to propose some design alternatives to help people respond to these signals better. With low cost and abundant of LED technology, the 3-light system can be built with a screen of LED lights.
Let’s take a look at these prototypes:
( *Animation and timing run faster for demonstration purposes )
#1 — The bold, meaningful text label can communicate clearly to people with impairments such as color blindness. A countdown timer would provide a visual feedback, so driver can anticipate when the signal will change and take out the guesswork.
#2 — The LED digitized display can sequence the information and maximize the space by not showing all three lights at once, so each message can be visible from a distance. Additionally, the digitized display can update the message according to the road conditions, and become more functional. Perhaps we can even delight drivers with a happy message!
William J. Beaty performed an interesting experiment: if you leave enough space between cars it helps to reduce traffic and benefits the system as a whole. The stop-and-go scenario can also apply to red lights. Why waste energy when you know the red light is up ahead? Drivers can coast with stored momentum or use regenerative braking to slow down and save energy. Braking can sometimes be avoided if speed can be modulated based on calculations of timing, velocity, speed limit, slope and weather conditions to determine what’s ahead.
Drive too fast and you arrive at the next light too early, which means you have to slow down or stop. To confirm this experiment, I gamified my daily 30 minute commute into a fun experience. Whenever I don’t have to stop completely, I got a point. By timing the red and green traffic light patterns correctly, and driving at the optimized speed. I only needed to use the brakes a few times.
Why do traffic lights still change when there is no traffic?
Smart traffic lights should sense its surrounding and adapt according to traffic conditions.
Before we head into a future of driverless vehicles there will be a transient period of time where the first autonomous cars must still coexist with error-prone human drivers. During this time, we must continue to rely on visual cues such as lights and signs to control traffic.
With a proliferation of sensors installed in vehicles and on every corner in the future, the traffic light will react based on real-time traffic and adjust intelligently with users’ need. It is possible to find the most efficient traffic light schedule at that particular intersection at any given moment.
I hope these ideas will bring more awareness of accessibility to all designers, civil engineers, and city planners. By working together, we can apply human-centered design to solve challenging problems and bring positive impact to the society.
When truly autonomous driving finally becomes a reality, there will no longer be a need for traffic lights at all.
I am optimistic about the future of technology. When sophisticated machine learning algorithms and car-to-car communication become reality, we will not need traffic lights in the age of autonomous driving. Perhaps we can end tomorrow’s traffic problems, thus saving countless hours for everyone.