By Robbie Webber
A Portland app developer may change the way we count bicycle traffic if his $50 device works as planned. As bicycling grows as a transportation choice, cities have been getting serious about counting how many people are using the paths, bike lanes, and local streets. But counting bicycles is a little more complicated than counting cars, and the methods and accuracy are still evolving.
There are generally two ways to count bikes: automatically and manually. They each have their advantages, but neither is ideal. Automatic counters are set up in high-traffic areas and can be run 24 hours a day, every day, in all weather. Whether they are accurate under even the best conditions is a matter of research, debate, and often depends on making sure the sensors are properly calibrated. Automatic counters tend to be expensive on a per-unit basis, which is why they are usually set up only in key corridors.
Bikes can also be counted manually, and even locations with automatic counters should be checked by a manual count to be sure the count is accurate. But manual counts depend on humans, and that means lots of volunteers or paid staff, plus more time to enter the data. And manual counts are generally done only at peak commute times and on specific days.
Portland has probably the best bicycle-count database in the U.S. Their manual counts are done once a year, at 200 locations, from 4:00-6:00 PM. They also have automatic counters on three key bridges and two other locations. But with only one citywide count per year, and only at evening peak commute, there are a lot of bike trips being missed: midday shopping, weekend social visits, sporting event traffic, and evening dinner trips. People who commute off-peak are also missed. And weather, special events, and traffic detours can wreak havoc on annual counts.
What William Henderson is working on is a device that would be able to count bikes accurately for only $50 per unit. That would allow cities to place counters in many more locations, capturing a truer picture of where, when, and why people bike. As new infrastructure is built or changes are made to make a route more bike-friendly, it would be much easier to install a counter and see changes in bike traffic patterns.
The way the device detects bikes isn’t new—a combination of a distortion in the magnetic field and an infrared camera calculate the speed and size of the object to determine whether it is created by car, bike, or pedestrian. But instead of needing a dedicated cellular connection to upload the information, Henderson’s device transmits counts via Bluetooth to an app that city staff, or any interested individual, installs on their phone. When a phone with the app passes by, the data is uploaded to the phone and later sent to the city’s database when the phone makes a cell or wi-fi connection.
Portland will be testing the devices at 200 locations around the city. They still plan to do manual counts, at least until they find out whether the device is reliable. But if it works, cities will have a much cheaper, easier way to count bikes in locations and at times that are being missed now.
Robbie Webber is a Senior Associate at SSTI.
By Robbie Webber