Smarter, Safer Roads by Design
November 8, 2016
John W. Carpita, PE
Category: Streets and Sidewalks
A while ago, I asked a group of city and county PWDs/Engineers these questions: “What neat and innovative things are your public works consultants and contractors doing on your road projects and what is on your wish list?” Aside from this tongue-in-cheek response: “I’m anxious for pre-striped, asphalt roads that come in big rolls, like sod,” no one responded. This probably means that no one can afford the time to respond to inane questions even though, each year, state and local agencies are doing really cool and innovative roadway and traffic management projects using ever more advanced techniques.
Driverless cars, smart phone traffic apps, the Internet of Things, and other wonders of our marvelous, cloud-based computer technology will greatly impact how local and state agencies design roads and traffic management systems for the future. “Smart roads” are, indeed, headed our way.
What is a smart road? Much like your average teenager, it’s a road that talks back to you. New—but seemingly farfetched—ideas abound on the Internet: intelligent transportation systems, pavement and structure monitors, interactive road/street lights, luminescent pavement markings, temperature sensitive traffic paint—the list goes on. Some of these are reality, some are in development, and some, elusive at best. Here are a few of my favorites.
We are light-years away from building entire freeways using solar panels that could generate electricity on a commercial scale, as some folks envisioned ten years ago. A trial installation called SolaRoad on a pedestrian/bicycle path in the Netherlands highlights this technology’s possibilities and pitfalls. Closer to home, Solar Roadways in Sandpoint, Idaho, has installed solar panels in the city’s Jeff Jones Town Square and will be installing panels on a rest area sidewalk on Route 66 in Missouri. Skepticism abounds, however.
One of the potential uses of this technology is as skid-free, LED-lit panels buried in roadway intersections to augment signage and conventional warning lights. Even a texting driver couldn’t fail to notice if the crosswalk suddenly erupted in flashing, multicolor lights!
Temperature Sensitive Traffic Paint and/or Pavement Temperature Apps
I’m sure that many of you have experienced moments of sheer terror when you’ve hit a patch of black ice. One smart road project, still in the conceptual stage, involves traffic paint that changes color or produces a holographic snowflake when the road temperature is at freezing.
Entirely feasible with today’s solar-powered, wireless transmitters are temperature sensors on bridge decks and other locations exposed to windchill that can send warnings to a smart phone via an app or to a vehicle via a dashboard warning. Automated deicing systems, widely used across Europe and Canada, use a similar technology to keep bridges safe in freezing weather.
Results of field tests using an epoxy overlay called SafeLane Ice Prevention Overlay have been positive. This overlay stores liquid deicer and automatically releases it when needed. The product was applied to a bridge in Wisconsin, where icing conditions had contributed to multiple accidents each winter. In a trial conducted over the course of two winter seasons, no accidents were reported. Note these case histories.
Safer Roads by Design
Where technology has not yet provided a solution, good planning can also keep roads safe. Wired recently published 16 Ways to Design a Better Intersection—and Better Cities. Included in this list were standards like sidewalk cafes, trees, and corner stores—which increase street side appeal—as well as traffic sensors, 4-way scrambles, and dedicated bus shelters—which improve movement on foot, bike, or in a motorized vehicle—with the takeaway being that good street design facilitates the flow of all types of transit, not just cars.
Seattle has one of the lowest pedestrian fatality rates in the country, thanks to careful planning. The city’s 30-year old neighborhood traffic calming program, with its emphasis on traffic circles, speed humps, and other measures, has served as a model for other cities.
More recently, Seattle installed hundreds of pedestrian countdown signals, protected bike lanes, bike boxes, and marked crosswalks across the city. Underlying this approach are city policies that establish six essential functions of the street in the public right-of-way and direct planners to accommodate as many as possible in making right-of-way decisions. These functions include:
- Mobility (moving people and goods)
- Access for people (e.g., bus stops and short-term passenger vehicle parking)
- Access for commerce
- Activation (e.g., parklets)
- Greening (street trees, green stormwater)
- Storage (e.g., long-term storage of vehicles)
Seattle has received praise both for this approach and its results. The National Association of City Transportation Officials’ Transit Street Design Guide, a toolkit for optimal street design, includes Seattle’s Bell Street Park as “a model case to reimagine the right-of-way as both a thriving open space and an important transit connection.”
What has your city/town done to create smarter, safer roads in your locale? Leave a comment below or contact me directly at firstname.lastname@example.org.
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