The Traffic Model Deceit: How Highway Agencies Manipulate Data To Justify Wasteful Expansion

For decades, state and federal highway agencies have justified massive projects with traffic forecast models. But a closer look reveals a troubling pattern of exaggeration, manipulation and outright falsification in these models.

Top StoryBenjamin Ross and Joseph CortrightOctober 23, 2024end highway expansion, traffic projections, induced demand, engineering ethics, congestion Be the First to Comment

Ignoring Induced Demand is Engineering Malpractice

In 2022, denying how highway expansions induce people to drive more should be considered professional malpractice.

Marohn, Top StoryCharles MarohnApril 4, 2022transportation, transportation spending, highways, freeways, engineers, engineering ethics, traffic engineering, traffic projections, induced demand, virginia, end highway expansion 42 Comments

Why Do We Have to Handle 30,000 Trips per Day?

When engineers say a street must accommodate a high volume of traffic, what they really mean is, "The design of this street must prioritize the convenience of commuters over all else."

Marohn, Top StoryCharles MarohnFebruary 7, 2022traffic projections, traffic engineering, engineers, transportation, highways, freeways, freeway widening, public engagement, minnesota, end highway expansion 8 Comments

Jarrett Walker: "Prediction and Freedom Are Opposites"

Special guest Jarrett Walker shares his thoughts on the limitations of prediction.

Podcast, Top StoryStrong TownsJanuary 24, 2022podcast, projections, traffic projections, transit, public transportation, urban planning Be the First to Comment

More Highways, More Driving, More Emissions

Fact: New roads always produce new driving. Say hello to “induced demand.”

Top StorySteve DavisNovember 11, 2021transportation, transportation spending, DOT, induced demand, traffic projections, highways, freeway widening, freeways, urban freeways, highway spending, environment, traffic engineering, end highway expansion 6 Comments

10 Reasons to Not Trust ODOT's Environmental Claims

Oregon’s Department of Transportation is making phony claims that widening highways reduces pollution. Here’s why they’re wrong.

Top StoryJoe CortrightOctober 26, 2021traffic projections, traffic engineering, traffic congestion, highways, freeway widening, freeways, environment, end highway expansion, oregon 5 Comments

All Traffic Models Are Wrong

Traffic engineers use projections of future traffic to make recommendations and decisions on transportation investments… The problem is, those projections are all wrong.

Marohn, Top StoryCharles MarohnSeptember 7, 2021traffic projections, traffic engineering, engineers, confessions of a recovering engineer, infrastructure 3 Comments

The Projections Fallacy

We spend billions every year on our transportation network, large percentages of it based on traffic projections—despite the fact that we don’t accurately project traffic.

Marohn, Top StoryCharles MarohnAugust 16, 2021traffic projections, traffic congestion, engineers, transportation, traffic engineering

Carpocalypse Never?

Why do predictions of “Carmageddon” so often fail to materialize? Recent lane reductions on a major bridge in Portland may hold answers, if we pay attention.

Strong TownsSeptember 30, 2020traffic congestion, traffic projections, oregon 6 Comments

A Reminder for Planners: "Every Projection is Wrong"

Put away the Excel sheet and go for a long walk.

Herriges, Top StoryDaniel HerrigesMarch 3, 2020infrastructure cult, traffic projections, projections, urban planning 1 Comment

Car-pocalypse Not Now: Why Predicted Gridlock in Seattle Was (Again) a No-Show

Why are we still surprised when a highway closes and fears of traffic pandemonium don’t come to pass?

Top Story, HerrigesDaniel HerrigesJanuary 31, 2019induced demand, traffic projections, congestion, washington 7 Comments

Big Bad Data: The Uninformative Inrix Scorecard

Big data should be used for problem solving, not propaganda and promotion.

Joe CortrightFebruary 13, 2018traffic projections, data, traffic engineering 2 Comments

Predictive Planning

A mechanistic approach to city problems exposes us to two harms: one is that we employ the wrong solutions. The other is that we actually make things worse.

Top StorySpencer GardnerSeptember 18, 2017traffic projections 1 Comment

Why urban freeway expansion is futile

The models used by highway engineers to analyze traffic congestion are woefully inaccurate and result in the creation of lanes and roads we don't need.

Top StoryNorm MarshallAugust 10, 2017highway spending, congestion, traffic projections, traffic engineering 9 Comments

The Economics of the I-49 Connector, Part 2

The probability of the I-49 Inner City Connector creating 30,600 new jobs that would not have simply occurred somewhere else or are just being shifted from one now blighted place to the study area is precisely zero.

MarohnCharles MarohnFebruary 22, 2017highway spending, economics, traffic projections, traffic engineering 10 Comments