Using open-source hardware and software with bikes to advocate for safer streets
We describe a bike outfitted with two ultrasonic ranging sensors, two cameras, a GPS, a real-time clock, and an inertial measurement unit containing an accelerometer and gyro. Together, this array of open-source sensors has allowed us to determine when and where motorists adhere to the “3 foot law” in several key roadways the US city of Atlanta, GA. In addition to overtake distance, the system permits the cyclist to determine their absolute speed, their absolute position and time, the relative speed of overtaking cars, road surface roughness, and incline. We propose dimensionless number that serves to rank the safety of bike lanes (and other infrastructure) across the region of study relative to an abstract “perfect” reference bike lane. Both the bike and instrumentation were developed at open-access and DIY organizations in Atlanta such as the Sopo Bicycle Cooperative. We hope this presentation will provide insight to others wishing to integrate open-source electronics with bicycles.