If you ride a bike in an urban environment, you probably have an anecdote or two (or 50) about being passed too closely by a driver.

This past fall, a Pittsburgh-based tech company that aims to “elevate the way people talk about and advocate for people-powered transportation” engaged four cyclists in an experiment to quantify just how often that happens on a stretch of road in the East End.

The pilot utilized TransitSource’s Sentinel Box, which “interfaces with the cyclist’s smartphone to record GPS location, time of day, passing distance, moving speed of the passing vehicle and a picture of the event.” The test, conducted as part of the city’s PGH Lab, allowed TransitSource to “see what our product was made of,” co-founder and managing director Allison Plummer told The Incline.

A 1.6-mile stretch of North and South Negley Avenue, from Fifth to Stanton avenues, was a good candidate for the study corridor for a few reasons, Plummer said. The avenue is currently listed by Bike Pittsburgh as a “cautionary route,” meaning it can be “more stressful” to ride than others and hard to avoid.

It’s also slated to get bike lanes. By collecting data before and after the lanes are installed, the city will have actual data to measure a difference in safety, Plummer said.

The Sentinel Box provides an “opportunity to make a change before damage is done,” Plummer said, and to “step away from reactionary” decision making.

Here’s how the pilot worked: Four volunteers who regularly use Negley as part of their bike routines each used a Sentinel Box for seven weeks.

The data showed “that every second trip, our volunteers were experiencing one unsafe encounter on average,” Plummer said. An unsafe encounter was defined as a vehicle passing closer than 4.5 feet from a cyclist.

In Pennsylvania, drivers are required by law to put at least four feet between their vehicle and a person riding a bike when passing. The extra six inches factored in the placement of the Sentinel Box between the bikes’ handlebars.

Plummer, a cyclist who’s “quite experienced on that route,” said the results matched what she expected. But more importantly, the pilot allowed TransitSource to “hone in on which blocks were the most problematic” and to find the pinch points.

The most unsafe passes, for example, happened between Baum Boulevard and Friendship Avenue. (S. Negley divides East Liberty and Friendship there.)

TransitSource presented its findings to Kristin Saunders, the city’s bike and pedestrian coordinator. In this instance, there’s not much the city can do with the data in terms of planning — the Negley Avenue lanes are essentially set. But the data provides a baseline for safety.

Once the lanes are installed — which should begin sometime in late March or April, depending on the weather — TransitSource will again ask its Negley Avenue volunteers to use the Sentinel Boxes to collect “after” data.

In the future, you may be seeing more Sentinel Boxes in Pittsburgh.

Plummer said TransitSource has applied to BetaBurgh, a grant program that allows “local and regional entrepreneurs and early-stage businesses to use their products for implementable ideas that activate public spaces in Downtown Pittsburgh.”

TransitSource’s proposal would retrofit a small number of Healthy Ride bikes with Sentinel Boxes and offer free rides to incentivize people to use them. Collecting that information would allow the city “to bring more attention to what biking is like Downtown and where we could target our efforts to see the greatest change.”

The company is also applying to an innovation challenge in Colorado that aims to reduce pedestrian and cyclist deaths. Getting that opportunity would allow TransitSource to deploy 50 devices and “actually [start] to scale, which is exciting,” Plummer said.

Currently, the Sentinel Box is TransitSource’s only product. Plummer said the company she co-founded with her brother, Ethan, is focused on “building products centered around active transportation.” The amount of tech and research that goes into automobile infrastructure planning is so much greater than planning for bikes, she said, and TransitSource is working to “level the playing field.”

“It’s like if Bike Pittsburgh … were a tech company,” she said.