Nearly every cyclist has been stopped at one of those traffic lights that never seems to turn green. That often leads to the rider running the light, which not only worsens cyclists' reputation in the eyes of motorists but also can have deadly consequences. However, many cities are starting to incorporate new tech that can sense when cyclists are waiting at an intersection and cut their wait times.
Currently, stoplights at many intersections are triggered by induction coils imbedded in the blacktop. The sensor detects the iron and steel in a car or truck and triggers the light. However, bicycles made of aluminum and carbon fiber, the two most common materials for new cycles, often don't contain enough metal to be detected.
"At those intersections, cyclists would have to get off their bikes and push the pedestrian crossing button," said Ross Sexter, Director of Business Development, Intelligent Traffic Systems division at Flir, a manufacturer of these sensors. "It's inconvenient. A cyclist should have the same rights as a motorist, who doesn't need to get out of his car to push a button."
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Cities in more than 20 states, including cycling meccas such as Portland, Oregon, and Minneapolis, are now installing thermal imaging sensors at lights. In addition to the heat being generated from a vehicle, these sensors can detect heat from a body several hundred yards away. The thermal sensors are well over 90 percent accurate at detecting cyclists, according to independent tests, Sexter said.
If a thermal sensor detects a cyclist arriving toward the end of a green light, it can signal the light to remain green until the rider can safely travel through the intersection. The sensor can tell the difference between cars, motorcycles, and bicycles to create detailed counts for traffic surveys and potential grant applications. Several cities plan to incorporate the data into their infrastructure master plan updates.
In Madison, Wisconsin, where more than 6 percent of residents commute by bike and officials believe that number will grow exponentially, the city recently began a test program of the devices. Assistant traffic engineer Scott Langer was one of many who are impressed so far.
"There's a lot of potential here," Langer said. "This could be big for our city, letting us know how we're doing and what we need to improve on. Madison is sandwiched between two lakes and an isthmus, so we can't build too many more roads. We see bicycling as a way to continue to grow without the congestion issues of big cities."
The sensors are crucial for not only efficient traffic flow but also safety.
"If bikes aren't being picked up by a loop, it may lead to the cyclist making a bad decision when the light doesn't change," Langer says. "That could cause the cyclists to ignore other traffic lights if they're under the perception the loops don't work."
There are drawbacks to the current devices, mainly, the sensors can't yet differentiate between pedestrians and cyclists, negating their use on pathways to count bike commuters. But Flir's engineers are confident they can resolve that issue, Sexter says.
He estimates it would cost up to $16,000 per intersection to install the sensors, about the same cost as the induction coils when construction costs are factored in. Retrofitting older model thermal sensors would cost less than $3,000.
After spending nearly a decade as a reporter for The Indianapolis Star, Robert Annis finally broke free of the shackles of gainful employment and now freelances full time, specializing in cycling and outdoor-travel journalism. Over the years, Robert's byline has appeared in numerous publications and websites, including Outside, National Geographic Traveler, Afar, Bicycling, Men's Journal, Popular Mechanics, Lonely Planet, the Chicago Tribune, and .