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Why Not Both? Dynamic Crosswalks To Optimize Pedestrian Choice And Vehicle Throughput

A proposal to prototype virtual, dynamic crosswalks which appear and disappear based on pedestrian demand and directional intent

Photo of Mitch Turck
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The inconvenient truth about pedestrians is that their flexibility makes them easy to ignore in street design. We have to put thought into vehicles, parking, bikes... but because it's so easy to ask pedestrians to go out of their way, consideration for them has traditionally come last, if at all.

As a result, we get city streets that aren't walkable (a vicious cycle leading to decreased economic viability and variety), and a rift between pedestrians and traffic law (also a vicious cycle, where pedestrian citations often lead to suspended licenses and, subsequently, more severe issues.)

While there are many champions for pedestrian rights, the cause is frequently thwarted by an inability to prove there is enough demand (and political support) to justify street and intersection redesigns that appear to detract from incumbent demand (vehicle throughput.)

What's being proposed here is the development of a "crosswalk projector" device which feeds directly on pedestrian demand. The idea -- and it is just an idea, to be sure -- is that an overhead streetlamp projector (or other lighting device) could dynamically create crosswalks of all shapes and sizes, at corners and mid-block alike, based on a prioritization algorithm taking into account the current vehicle throughput vs. current pedestrian demand (i.e., number of people waiting to cross in a given area.)

Optimally, whatever pedestrian sensors are utilized (computer vision in-device, or a companion sidewalk pressure pad/visual sensor, etc.) would recognize the intended direction of each pedestrian, and once demand reaches critical mass -- be it one person trying to cross the middle of a block with no cars approaching, or 200 people crossing while ten cars approach -- the overhead lighting device would light up a temporary crosswalk pattern encompassing all the pedestrians' desired paths, or regressing closer to the mean if some pedestrian intentions are too far outside the bounds of the core demand. Once demand subsides, the crosswalk disappears, and vehicles start moving again.

In a more connected city, this dynamic drawing of crosswalks would be useful as a method of blocking off entire blocks during lunchtime, or creating unorthodox scrambles without having to permanently paint what is already the most visually bewildering section of any given road.

Again, in a more connected future, V2X technology could easily coordinate with vehicles to ensure safe crossing. But for now, the proposal theorizes that dynamic crosswalks would indirectly make streets safer even when not in use, as drivers would now be responsible for paying better attention and driving at a speed reasonable enough to stop for pedestrians at any given moment. The lighting device could assist with recognition, for instance by lighting up the crosswalk in a simulated 3d pattern:

There are more peripheral safety benefits, such as the ability of a projected crosswalk to work in snowy conditions, and the mitigation of any need for peds to stand on the curb or in the street prior to crossing. The sensors could identify waiting peds at a safer distance from the curb.

Lastly, the concept of building pedestrian demand dynamically through volume or wait time would serve to educate drivers and peds alike about the complex relationship between choice and throughput. While this proposal seeks to improve pedestrian choice, it also aims to teach all road users the importance of prioritization -- making them better-informed to decide in each community just how much to dial up or down the pedestrian demand that triggers these crosswalks.

I've discussed the idea in further detail here, but again, I want to clarify that the funding would go towards building a prototype for one intersection. The technology is the biggest hurdle, and beyond proving it's technically feasible, observing it in action at one major intersection should provide enough commercial validation to expand it across (and beyond) the city.

Describe who will use your solution (1,000 characters)

All pedestrians and vehicles within the solution's area(s) of operation. Pittsburgh is no stranger to dangerous intersections (https://triblive.com/local/allegheny/13777290-74/the-10-most-dangerous-intersections-for-pedestrians-in-allegheny-county). Placing the prototype at one high-pedestrian-traffic intersection in Downtown, Oakland, Southside or Lawrenceville should yield enough economic data and user feedback to validate or revise the solution... but placing it at one of the most dangerous intersections may provide more immediately measurable safety results.

Describe your solution's stage of development

  • Initial Design - you are still exploring the idea and have not tested it with users

Tell us about your team or organization (500 characters)

I've been covering the future of mobility (specifically, autonomous vehicles) independently for the past four years, writing for Forbes.com and Medium.com. During that time, I've worked with several automotive sector corporations and design firms to prototype user experiences for autonomous vehicles and smart cities. I have no financial stake in the success of this proposal.

Size of your team or organization

  • I am submitting as an individual

Funding Request

  • $75,000

Describe how you would pilot your idea (1000 characters)

The vast majority of the $75,000 would go to developers engineering the device(s). Building a viable prototype is the most immediate and important step. Once built, the prototype would be rolled out to one notable city intersection, where any remaining funds could be used to create on-site educational material. A scalable product of this type (reasonable production times, low bill of materials) would be unquestionably valuable to cities worldwide. It's an immense market opportunity, and results of the Pittsburgh pilot would provide enough momentum to feed a natural sales pipeline. In that sense, this $75k is really most akin to an angel investment in a device/IoT startup.

Describe how you would measure the success of your pilot (1000 characters)

Milestone 1: successful prototype (can effectively light up crosswalks dynamically in 99.9% of weather conditions, can identify pedestrian volume reliably via CV or companion sensor device, identifying pedestrian direction intention a plus) Milestone 2: three-month study of pedestrian and driver satisfaction Milestone 3: six-month study of economic improvement Milestone 4: twelve-month study of safety improvement (decrease in crashes, pedestrian injuries, deaths)

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Photo of Diana Avart
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Hi Mitch,

Thanks for this post seeking to improve mobility for pedestrians. From my experience, the safest and most pedestrian-friendly crosswalks are those that stop traffic in all directions while pedestrians cross larger intersections. Not only do these crosswalks prevent drivers from trying to make turns into the crosswalk while pedestrians are crossing but also encourages pedestrians to actually wait for their turn since they will be able to take a safer, more streamlined path across the street.

Since a lot of the high pedestrian intersections already have this improved pedestrian technology, I could see piloting this idea in areas that have large influxes of people during specific times (sports games, concerts, festivals, etc.) but otherwise have a fairly normal amount of foot traffic on a regular basis and don't require motorized traffic to stop in all directions all the time. In a way, it provides the same scenario, but only when there is a high demand, helping maintain traffic flow when there is low demand. I could definitely see this working well on the North Shore and Downtown!

- Diana, Facilitator

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