by Matt Favero
There are many failed interactions I have with machines each day, but one human-machine interaction can potentially be catastrophic. That is, my experience with cars, specifically when crossing the road.
I walk to class every day. On Main Street in Blacksburg, there are convenient crosswalks at each intersection (depicted below).
I wait for the sign to light up instructing me to walk, and cars see a big red light telling them to STOP. However, on multiple occasions this system has failed me, resulting in the minor inconvenience of a near-death experience.
Of course, cars driving directly towards the crosswalk see two things: me crossing and a red light. But, what about cars driving parallel to the crosswalk, but turning towards it? Let me illustrate this:
Usually, drivers are looking forward. When they see green, they go; when they see red, they stop. The skidding red car in the diagram above sees GREEN on the traffic light above. He or she is turning left, and I’m quite possibly out of their field of vision. The crosswalk light has lied to the pedestrian – and the traffic light has lied to the driver.
First, I had to select a design process. Most of the design processes we discussed in class seem to require some observations of users. The AEIOU and concept mapping strategies, however, were more freeform and did not have this requirement. I ultimately chose to do concept mapping, because it was less rigid than AEIOU and I thought it would best catalyze brainstorming.
To draw a concept map, I started with the two users of the system: drivers and pedestrians. Then, I started brainstorming about three areas of interest when driving or crossing the road. These three areas are: symbols & cues (like traffic lights), checks (e.g. checking your blindspot), and motivations (e.g. get to the other side).
Below is the diagram I drew:
Once I began brainstorming, a few interesting dichotomies became clear. Both pedestrians and cars relied on colored lights to guide them; however, they relied on different colors and symbols. While I was at it, I looked up if color-blind individuals have issues telling red & green traffic lights apart. It turns out they do (in fact, 7-10% of the human population!), and new traffic lights have been proposed to remedy this (source).
Overall, the road has quite developed (and antiquated) systems for guiding drivers. In comparison, pedestrians have a less clear system. There is no pedestrian license or school like there is for drivers. As a pedestrian myself, I’ve noticed that some crosswalks are completely safe (there are no drivers who may turn into the crosswalk) whereas others I have to be alert for cars. Because of this lack of uniformity, pedestrians need a system that is universal and easy to understand.
On the other hand, I quickly realized during the design process that drivers have a considerably greater amount of things to check and worry about. They don’t have many free mental resources to be worrying about both what’s on the road, and what people are about to cross. Therefore, I came to the conclusion that the system needs to strongly accommodate drivers. New symbols and rules would only confuse drivers further.
My primary focus was to create a simple and universal solution to dangerous crosswalks. The goal is to completely remove ambiguity for drivers & crossing pedestrians, while preventing introduction of new symbols or rules to learn.
Lit signals are the primary instructor for drivers & pedestrians. My ultimate design was an illuminated crosswalk. I noticed the issue described arises primarily at night. By adding light to the crosswalk, pedestrians will be illuminated in the dark. The color white best accompanies the white crosswalk, and this illumination will light the way for a pedestrian to walk.
To implement the solution, a band of white LEDs may be added surrounding each crosswalk stripe. These will shine upwards, increasing the visibility of the surrounding crosswalk and pedestrians walking over. This has the added advantage of the light source being not at eye level, which would potentially be distracting.
Additionally, this accompanies a small motion detector at both entrances of the crosswalk. These detectors ensure the light is only on when a pedestrian is crossing, improving efficiency and light pollution. The final solution is both aesthetically pleasing and simple to implement.
I found this process fairly enlightening. I have always worried about crossing sidewalks ever since a few close encounters, but I’ve never actually considered solutions. Some seemingly-obvious questions arose I had never considered. Why do cars see green to go, but pedestrians see white? Perhaps because of antiquity. Why do drivers seem so careless towards pedestrians? Well, they have a lot more to worry about.
Composing the art for the project was also a fun process that enabled me to imagine the solution much easier. When I actually simulated the situation I had encountered, it became obvious that from the driver’s perspective, he or she needs some signal to say, “Hey! There’s a pedestrian on your left!” – and this is what I ended up upon. There were many ideas I considered (add a red arrow on the traffic light for these intersections, make a spotlight which tracks pedestrians, among others), but once I arrived at the illuminated crosswalk this seemed the easiest and most elegant.