I came across an interesting post at The Antiplanner debating whether autonomous vehicles will ultimately increase or decrease urban density.
The question is more interesting than it might initially sound. Some urban economists have argued that autonomous vehicles could encourage greater urban concentration. The author takes the opposite view: improvements that make transportation faster, cheaper or more convenient have historically allowed people to live farther from city centers, and autonomous vehicles are likely to continue that long-running trend toward decentralization.
Spoiler: I find that argument pretty persuasive.
But it was a different line in the post that really caught my attention:
Between 2014 and 2024, bicycle commuting in bike-friendly Portland dropped by more than 40 percent and in the nation as a whole by 12 percent.
That sounded dramatic enough that I checked it.
It is essentially correct. In fact, measured as a share of commuters, the decline in Portland was even larger.
In 2014, 7.2 percent of Portland commuters biked to work. By 2024, that had fallen to 3.2 percent — a decline of about 56 percent in bicycle commute share.
Nationally, the number of bicycle commuters fell from about 904,000 in 2014 to 803,000 in 2024, a decline of roughly 11 percent.
I found the Portland number especially interesting because, having lived in the Pacific Northwest, I was well aware that Portland — like Seattle — had spent years aggressively expanding its bicycle infrastructure. Portland was routinely held up as one of America’s model cycling cities.
That naturally made me wonder about Seattle.
I lived there for around 15 years, and it was impossible not to notice how much money, political attention and physical street space was being devoted to bicycles. Streets were reconfigured. Parking disappeared in places. Protected bike lanes appeared throughout downtown and other neighborhoods. Neighborhood greenways were built. Bicycle projects became an increasingly prominent part of Seattle’s transportation agenda.
So perhaps Seattle had bucked the trend?
The answer is more nuanced than I initially expected.
In 2014, 3.7 percent of Seattle commuters biked to work — about 14,157 people. Seattle ranked fifth among America’s 70 largest cities for bicycle commuting.
A decade later, after a substantial expansion of Seattle’s bicycle network, 3.5 percent of commuters biked to work in 2024 — about 16,700 people.
So unlike Portland and the nation as a whole, Seattle did not experience a decline in the absolute number of bicycle commuters. The raw number actually increased by about 18 percent.
But Seattle itself was growing at almost exactly the same rate.
Between 2014 and 2024, the city’s population increased from about 668,000 to 781,000 — an increase of nearly 113,000 people, or about 17 percent.
In other words, the number of bicycle commuters essentially kept pace with population growth. What it did not do was capture a larger share of Seattle’s commuting population.
Despite a decade of substantial investment in bicycle infrastructure:
Population: ~668,000 → ~781,000 (+17%)
Bike commuters: ~14,157 → ~16,700 (+18%)
Bike commute share: 3.7% → 3.5%
It’s a rather different story from Portland, where cycling’s commute share collapsed.
That is striking because Seattle spent a decade actively reshaping its streets to encourage cycling — investing tens of millions of dollars, reallocating road space, and building dozens of miles of bike lanes and greenways.
Yet after all of that intervention, cycling’s share of commuters was lower than where it started.
Using Seattle’s own capital accounts, the city’s principal bicycle-network capital program appears to have recorded roughly $99 million in actual spending between 2014 and 2024.
That isn’t the same thing as saying Seattle spent $99 million building bike lanes. The program also funded things such as neighborhood greenways, trail connections, bicycle signals and related street improvements.
But it is a reasonable measure of the scale of Seattle’s investment in bicycle infrastructure during the period.
And Seattle certainly built things with the money.
Under the Move Seattle levy, from 2016 through 2024 the city reports delivering approximately:
- 31.7 miles of protected bicycle lanes
- 4.8 miles of conventional bicycle lanes
- 39.9 miles of neighborhood greenways
That’s more than 76 miles of bicycle facilities, plus additional upgrades to existing greenways.
In other words, this was not a token investment or a case where the city simply failed to build the infrastructure advocates said was needed. Seattle spent heavily, built at scale — and bicycle commuting still failed to gain meaningful share.
There is an important caveat. The Census data measure the principal way people commute to work. They don’t capture every recreational ride, trip to the grocery store, restaurant visit or weekend outing. And Covid dramatically changed commuting behavior, particularly in Seattle, where working from home became extremely common.
So these numbers don’t prove that bicycle infrastructure produced no benefits.
A protected lane might improve safety for people who already cycle. It might make recreational riding more pleasant. It might encourage some trips that never show up in commuting statistics.
Those are legitimate potential benefits and should be measured on their own terms.
But Covid isn’t the whole explanation either.
Seattle’s bicycle commute share was 3.7 percent in 2014 and 3.7 percent again in 2019, immediately before the pandemic. It fell sharply during the work-from-home era and has since recovered substantially — to 3.5 percent in 2024.
So over the full decade, despite Seattle’s population growth, major infrastructure buildout and considerable spending, bicycle commuting’s share of workers essentially went sideways.
That seems worth paying attention to.
Who benefits?
There’s another aspect of Seattle’s bicycle policies that I’ve written about before.
Several years ago, in a piece on the contradictions inherent in some of Washington State’s progressive policies, I looked at who was most likely to have access to and use bicycles.
Seattle’s own transportation research found that residents with access to a working bicycle were disproportionately white, male and younger. More recent King County commuting data similarly show men cycling to work at more than twice the rate of women, with white workers among the groups with higher bicycle-commuting rates.
I wrote about that disconnect in a National Review piece entitled “The Incredible Whiteness of Washington State’s ‘Progressive’ Policies“
None of that means white men shouldn’t ride bicycles. I’m a white male and I’ve ridden plenty of them.
The public-policy question is different.
Who benefits from an investment? Who bears its costs? And what measurable result does the investment produce?
Those questions become particularly relevant when scarce street space is reallocated, vehicle lanes or parking are removed, and tens of millions of dollars of public money are spent — especially when those same decisions are frequently justified in the language of equity.
Inputs aren’t outcomes
What I find most interesting about the Seattle example is the distinction between inputs and outcomes.
Miles of bicycle lanes built are an input.
Dollars spent on bicycle infrastructure are an input.
Plans adopted, projects announced and lanes completed are inputs.
If one of the policy objectives is to persuade people to substitute bicycles for cars, how people actually travel is an outcome.
Seattle spent roughly $99 million through its principal bicycle infrastructure program over a decade and built dozens of miles of protected lanes, conventional lanes and neighborhood greenways.
Meanwhile:
Bike commute share: 3.7% → 3.5%
Bike commuters: ~14,157 → ~16,700 (+18%)
Seattle population: ~668,000 → ~781,000 (+17%)
In other words, the number of bicycle commuters grew almost exactly in line with Seattle’s population, while cycling’s share of commuters was essentially unchanged — and actually a little lower — after a decade of major investment.
Perhaps, absent all of that spending, bicycle commuting’s share would have fallen substantially. That’s possible.
Perhaps the principal return on the investment has been improved safety rather than increased ridership. That’s possible too — and measurable.
But those are quite different arguments from the familiar assumption that if cities simply build enough bicycle infrastructure, large numbers of people will respond by abandoning their cars and taking up cycling.
Seattle provides remarkably little evidence for that proposition.
And Portland — another city that enthusiastically built out its bicycle network — appears to tell an even more dramatic story. There, bicycle commuting’s share fell from 7.2 percent in 2014 to 3.2 percent in 2024.
That brings me back to the article that started me down this rabbit hole.
Transportation infrastructure unquestionably affects where and how people live. But policymakers have a habit of assuming that people will respond to infrastructure investments in the way planners want them to respond.
Sometimes they don’t.
Seattle built the bike lanes.
Bike commuting barely budged.
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