Economists and urban planners have known for decades that highway expansions can't solve traffic congestion.

Why, then, do so many states keep widening their roads?

A 🧵 about my deep dive in @CityLab…
Economist Anthony Downs gets credit for the idea of induced demand, but its roots go back *much* further than his 1962 article.

In 1927, engineer Arthur S. Tuttle warned that new urban roads “would be filled immediately by traffic which is now repressed because of congestion.”
In the 1920s and 1930s city officials worried about wooing suburbanites to shop and work, so they shrunk their sidewalks and ripped up public space to accommodate more cars.

It was a disaster. Congestion only grew.…
Even city officials who saw the futility of road expansion were stuck, because state gas tax revenues could often only be spent on roads (not transit).

It was new highways and wider streets—or nothing.

From Christopher Wells' book Car Country ⬇️
By the 1950s, a growing chorus of critics saw that urban highway expansions were pointless.

Lewis Mumford compared road widening to a man treating obesity by loosening his belt: “This does nothing to curb the greedy appetites that have caused the fat to accumulate.”
But power lay with highway officials, not with Mumford's audience.

History professor Mark Rose: “These guys dealt with traffic. Their primary constituencies were construction companies and road engineers.”

Minneapolis in 1953 and 2014, from…
Today, many states still earmark gas tax revenue for roads. That leads state DOTs to favor highway expansions that induce more driving, growing the DOT's budget.

Transit or congestion pricing won't do that.…
State agencies like TxDOT regularly exaggerate the benefits of highway widening – like the $7B expansion of Houston’s Katy Freeway to 26 lanes, which failed to reduce congestion.

The feds don't penalize states for getting forecasts so badly wrong.…
Meanwhile, construction and auto industries are happy to keep the public confused about induced demand (which can seem counterintuitive).

Here’s Elon Musk two years ago.
Some states, like California and Nevada, are starting to make real progress.

But plenty of others aren’t. Here’s a particularly ill-conceived project outside of Charleston, SC.…
And a potentially disastrous one in Austin, which locals are fighting furiously.…
What would it take for these states to acknowledge the futility of urban highway expansions?

The feds could help, by making VMT reduction (and accurate congestion forecasts) key evaluation metrics.

Halting TxDOT's I-45 expansion was an encouraging step.…
But until they're forced to, don’t expect agencies like TxDOT to acknowledge the futility of urban highway expansions.

They aren’t ignorant—they just prefer to maintain the wasteful, inequitable, and polluting status quo.…
BTW, to dig deeper into TxDOT's penchant for highway widening, I cannot recommend this article by @megankimble highly enough. It's a masterpiece.

(TxDOT invited me to submit questions via email, but they never responded to those I sent.)

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More from @DavidZipper

7 Sep
Flashy, complicated infotainment systems are creating a growing safety risk. And it's likely to get worse.

A 🧵 about my investigation, in @Slate…
Why worry about infotainment systems? They’re harmless and fun, right?

Well, not necessarily. A study by the AAA Foundation found that rerouting a destination can distract a driver for up to 40 seconds—enough time to cover half a mile at 50 mph.…
Even if a driver uses voice commands, systems often require looking at a car's touchscreen (and not the road) to verify accuracy. That’s inherently risky. Image
Read 14 tweets
5 Jun
A provocative question in this book by @STS_News: Why doesn't the USA regulate car safety like emissions?

"How would automakers transform their products if we mandated that they reduce the number of automotive fatalities in new cars by, say, 40% within 10 years?"

A thread 🧵:
For a century, automobile safety has largely focused on 1) driver education and 2) voluntary agreements by automakers to build safer cars.

Both those approaches are flawed.
Here's future Sen. Daniel P. Moynihan critiquing safety education in 1959:

It "shifts public attention from factors like auto design, which we can reasonably hope to control, to factors such as the temperament and behavior of 80M drivers, who [will ignore] a bunch of slogans."
Read 8 tweets
10 Apr
Just finished @shigashide's book about how to improve bus service—it’s good!

Loads of useful info about operations as well as advocacy. And a surprisingly easy read.

Short 🧵: Image
2/ Here's an excellent rebuttal to those (like Gov Cuomo) who claim fancy stuff like USB ports and wifi will attract loads of new riders: Image
3/ @humantransit is a clear influence, so I wasn't surprised to find this stinging critique of microtransit:

“When existing bus routes are unreliable and slow, focusing attention on microtransit is like trying to perfect dessert at a restaurant that routinely burns the entrees.”
Read 5 tweets
15 Mar
BREAKING-- Congress just released text of the “EBIKE Act," which would offer a refundable tax credit of up to $1,500 for a new e-bike purchase.


If it passes, the EBIKE Act would be groundbreaking. A 🧵:
2/ Why get excited about e-bikes?

They’re terrific for the environment. Check out this table from @ITF_Forum, comparing greenhouse gas emissions for major passenger transport modes.

3/ E-bikes’ extra pedal power makes them capable of replacing cars on the 50%+ of US trips under 6 miles (esp on hot days, or on routes with hills).

That would give a nice boost to health, the environment, and to street safety.…
Read 11 tweets
27 Dec 20
Stuck at home, I've read more books in 2020 than I have since college. 20+ have been about cities and mobility.

Because I like making lists, these were my favorites:

Order w/o Design is the clearest explanation I’ve seen about how transportation networks shape local economies—and why well-intentioned urban planning schemes often backfire.

Not a light read, but a brilliant one. Previous thread below.

.@SAShistorian's Policing the Open Road came out last year, but it already feels like a classic.

The American legal and criminal systems still haven’t figured out how to fit automobiles into the Fourth Amendment. Minorities and low-income residents pay the price.
Read 8 tweets
11 Nov 20
Oversized SUVs and trucks are a growing menace to people outside of them-- including pedestrians, cyclists, and occupants of smaller cars.

A Biden admin can begin fixing this (even w/o the Senate).

Here's how. 🧵⤵️
Some context: The National Highway Traffic Safety Administration (NHTSA) evaluates the design of new autos through its influential New Car Assessment Program (NCAP)-- aka, "the one with the crash test dummies."

Automakers are eager to score valuable ⭐️⭐️⭐️⭐️⭐️ NCAP ratings.

NCAP only looks at risk to a vehicle's occupants. Pedestrians, cyclists, and those in other cars don't count.

That gives automakers little incentive to protect vulnerable street users. Instead, they're in an arms race to design the biggest, tallest SUVs and trucks.

Read 9 tweets

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