Increased Ridership Often Means Increased Safety for Cyclists

While bicycle ridership has been boosted by improvements to infrastructure, what is keeping cyclists safest may simply be more of their own kind on the road.

1 minute read

October 11, 2010, 1:00 PM PDT

By Emily Laetz


An increasing amount of data suggests that common municipal investments in bicycle-specific infrastructure such as painted bike lanes and signage are a smaller component of rider safety than originally thought. Of growing importance is the theory that more riders means fewer crashes, because driver behavior is modified when cyclists have an increased presence on the street.

Elly Blue concludes that a steady stream of recent research backs the 'safety in numbers' theory, which was first identified in 2003 by public health researcher Peter Jacobsen. Looking at crash data from several communities, Jacobsen concluded that there is an inverse relationship between the quantity of cyclists in an area and the number of crashes involving cyclists.

Jacobsen theorizes that increased numbers of cyclists themselves cause people driving cars to become more aware, which thus leads to fewer collisions.

Blue writes:

"But when there are a lot of bicyclists on the road, according to this theory, drivers take notice. They become more attentive, slow down, pass more cautiously, double-check their blind spots, expect the unexpected. They sense that the road has become a more complicated place, and adjust their behavior accordingly. As a result, the road becomes safer, presumably for everyone."

Monday, October 11, 2010 in Grist

Young Professional

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban and Environmental Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban and Environmental Planner

Get top-rated, practical training for planners

"Planetizen federal action tracker" logo superimposed over black and white image of US Capitol dome.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

September 16, 2026 - Zachary Whalen

Passengers board an Amtrak train under a cloudy sky.

Amtrak, CN end decades-long dispute with eight-year agreement

The new operating agreement establishes an updated framework for the companies to work together, including processes to resolve disputes.

September 18, 2026 - Mass Transit

The Gross Reservoir, a large body of water surrounded by trees and mountains.

Judges permit Denver to divert 77,000 acre feet from the Colorado River for reservoir expansion

Overuse and climate change have caused the Colorado River’s water levels to plummet.

September 18, 2026 - Inside Climate News

A crowd of people boarding Boston's green line in an underground subway station.

Boston has spent millions making the Green Line more accessible — and there’s no end in sight

While the city has invested millions into expanding and adding platforms to the Green Line to make it more accessible, new train cars set to arrive next year will be too tall for disabled passengers to board without raising the current platforms.

2 hours ago - Boston Globe

Railroad tracks in Idaho passing a home by a river.

Idaho may see an 18% drop in federal surface transit funding — the largest estimated cut in the US

Transit systems in rural communities are much more reliant on federal funding to provide their services.

3 hours ago - Grist

A Florida family with their belongings in a wagon walks past a destroyed storm after a hurricane.

How ‘post-disaster gentrification’ alters neighborhoods after natural calamities

After hurricanes, fires or other calamities, the original residents of a community are often replaced by younger, wealthier residents.

4 hours ago - Inside Climate News