Tackling the invisible threat of black ice

For the sixth year, The Lemelson Foundation is giving $100 awards to outstanding young inventors in Society Affiliate Fairs with middle school participants around the country. The prize was created to reward young inventors whose projects exemplify the ideals of inventive thinking by identifying challenges in their communities and creating solutions that will improve lives.

Imagine driving along a quiet coastal road in California and suddenly, your car begins to skid uncontrollably on what appeared to be dry pavement. This hidden danger, known as black ice, is an almost invisible hazard that has led to over 144,000 casualties annually in the United States, according to the Department of Transportation. For Sanvi Kannoori, who lives in San Jose, Calif., this issue became personal after a frightening and unusual experience with black ice on a coastal road inspired her to find a solution. She explained, “Along the coast where it reaches significantly chill temperatures with water vapor from the ocean, the perfect environment is created for black ice to form.”

“My family and I were stuck on black ice because we never even saw it coming,” Sanvi explained. “Thankfully, we made it to safety, but not everyone is as lucky.” Sanvi wanted to help her community and drivers everywhere by developing a tool that could help drivers identify and avoid black ice.

Black ice forms as a thin, transparent layer on roads and pavement surfaces, typically in cold temperatures. “Black ice is so dangerous because it is very hard to identify, especially at night when it almost completely blends in with the pavement,” Sanvi shared. Drivers traveling at high speeds can unknowingly encounter black ice, leading to a loss of control, skidding and potentially accidents that can even be fatal.

“Being aware early that a driver is on black ice before skidding is something that could save thousands of lives,” Sanvi said.

When researching existing black ice detection solutions, Sanvi said she was surprised by the lack of affordable and effective devices on the market. “I searched for already existing solutions, but there are barely any marketed black ice detectors that are of an affordable price,” she said. Existing devices, priced between $100 and $2000, mainly rely on temperature sensors, which can be flawed due to changing air temperatures.

“The major difference between black ice and regular pavement is the way black ice reflects light,” Sanvi explained. Ice reflects more light than pavement. Sanvi designed a prototype that could differentiate between ice and pavement using something called a photoresistor, a sensor that changes its resistance based on the amount of incoming light — the greater the light reflection, the lower the resistance. Sanvi also added a monitor that would alert drivers when they were approaching black ice.

“By using specialized algorithms that distinguish black ice from regular pavement based on their reflective properties, the detector can not only detect the ice but can display U.S. Department of Transportation- approved instructions, on how to handle black ice,” Sanvi explained. The device is composed of a circuit, a Raspberry Pi and an LCD monitor. “The circuit and Raspberry Pi are placed underneath the car,” Sanvi said, “allowing it to gather the most accurate data continuously, while the monitor is placed on top of the car” to alert the driver of any black ice.

Sanvi shared that studying how a Raspberry Pi works was her favorite part of her research project. While she was already familiar with coding in Python, she explained that using the language to code a separate device was a new challenge. “Although I was stepping into new territory and running into multiple coding issues, it certainly was my favorite part because of how much I was able to learn,” she said.

Sanvi’s research project earned her a Lemelson Early Inventor Award at the Synopsys Silicon Valley Science and Technology Championship. “My invention helps drivers have an extra pair of eyes, and if they do get stuck in a black-ice region, they have the instructions they need to get to safety. But of course, the detector is mostly built for helping the driver avoid black ice in the first place,” Sanvi said. She hopes that someday she can develop a device that can be incorporated into a car design.