As some of the lowest-emission vehicles in existence, pedal bicycles and e-bikes are critical tools in the battle against climate change. This makes safe urban cycling infrastructure essential.
And contrary to popular belief, simply adding more bicycle lanes may not be what’s needed.
The Atlanta study
According to a recent study conducted in Atlanta, bicycle lanes that are solely marked with paint may lead to an increase in accidents between drivers and cyclists. Even protected bicycle lanes that transition to paint at intersections could be hazardous for riders.
The study, published in the Journal of Transport and Health, found that painted bicycle lanes and sharrows had adverse effects, resulting in more collisions compared to roads without any painted markings. In contrast, off-street trails and protected on-street lanes demonstrated significant protective effects. This was even true when there were minimal curbs or plastic flex posts to separate cyclists from drivers.
The researchers analyzed police reports and bicycle ridership data spanning 23 months to estimate crash rates per mile on streets with various types of bike infrastructure. By comparing these rates to a hypothetical model based on surrounding corridor data, the study aimed to determine which interventions are most effective in reducing fatalities.
However, the researchers acknowledged that their analysis had limitations due to the lack of comprehensive bike data in the US and the small sample size from a single city.
However, even when accounting for area-level household income and population density, the study found that painted-only bicycle lanes and sharrows were still riskier than roads with no designated bicycle infrastructure. The researchers couldn’t pinpoint exactly why this was the case.
The Atlanta study was especially puzzling considering that previous studies in different communities had reached the opposite conclusion.
The lead author’s take
According to Michael Garber, the lead author of the study and a postdoctoral fellow at UC San Diego, it’s possible that more experienced and confident cyclists are more inclined to use painted bicycle lanes. This may cause drivers to expect them to move out of the way.
Garber, however, acknowledged that it was often homeless people who use bicycle lanes in areas with heavy car traffic.
Garber suspects that Atlanta’s unsafe painted-only lanes result from their placement on already dangerous roads, contrary to guidelines from the National Association of City Transportation Officials. These guidelines recommend painting “conventional” bicycle lanes solely on narrower roads with minimal cars and vehicle speeds below 25 miles per hour.
The researchers highlighted that several buffered and conventional bicycle lanes in the study area failed to meet these criteria. One bike lane was located along a busy arterial road that experienced five times the average daily traffic recommended for a paint-only bike lane.
According to Garber, the designated lanes in the Atlanta sample often transitioned into regular crosswalks without safety features like corner islands, which would help motorists spot oncoming riders. As a result, drivers frequently blocked bike lane entrances and exits, forcing riders to take risky evasive actions.
According to Streetsblog USA, Atlanta is planning to dramatically expand its biking infrastructure. The city will invest $5.2 billion investment in bicycle and pedestrian projects by 2050. It remains uncertain whether new bicycle paths will be designed in a safe, context-sensitive manner or if they will simply be paint markings next to fast-moving traffic.
Garber believes that traditional bicycle lanes don’t significantly improve safety and may even pose risks in certain scenarios. He agrees that paint alone is insufficient for protection.
Image Source: Bike Tarrytown, https://shorturl.at/bEV19