David Zipper
@davidzipper.bsky.social
Senior Fellow @ MIT Mobility Initiative & Contributing Writer @ Vox, focused on transport, cities and tech. Words in Atlantic, CityLab, WaPo, etc. https://linktr.ee/davidzipper
Newsletter, speaking and advisory work: http://davidzipper.com
Newsletter, speaking and advisory work: http://davidzipper.com
My take on Mamdani's ambitious vision for revamping NYC streets:
"The NYC DOT Commissioner position is going to be the most exciting job in American transportation."
From the latest @lookbothwayspod.bsky.social (please ignore my crooked glasses):
lookbothwayspod.podbean.com/e/episode-9-...
"The NYC DOT Commissioner position is going to be the most exciting job in American transportation."
From the latest @lookbothwayspod.bsky.social (please ignore my crooked glasses):
lookbothwayspod.podbean.com/e/episode-9-...
November 13, 2025 at 4:08 PM
My take on Mamdani's ambitious vision for revamping NYC streets:
"The NYC DOT Commissioner position is going to be the most exciting job in American transportation."
From the latest @lookbothwayspod.bsky.social (please ignore my crooked glasses):
lookbothwayspod.podbean.com/e/episode-9-...
"The NYC DOT Commissioner position is going to be the most exciting job in American transportation."
From the latest @lookbothwayspod.bsky.social (please ignore my crooked glasses):
lookbothwayspod.podbean.com/e/episode-9-...
November 12, 2025 at 8:37 PM
BTW, a 2021 Carnie Mellon study found that ridehail's arrival in a new city *increases* car ownership.
The reason: Few residents ditch their car, while some become ridehail drivers and buy vehicles.
www.cell.com/iscience/ful...
The reason: Few residents ditch their car, while some become ridehail drivers and buy vehicles.
www.cell.com/iscience/ful...
November 12, 2025 at 8:34 PM
BTW, a 2021 Carnie Mellon study found that ridehail's arrival in a new city *increases* car ownership.
The reason: Few residents ditch their car, while some become ridehail drivers and buy vehicles.
www.cell.com/iscience/ful...
The reason: Few residents ditch their car, while some become ridehail drivers and buy vehicles.
www.cell.com/iscience/ful...
Remember all the hype about how Uber and Lyft would allow people to live car-free?
Well, it turns out ridehail has no discernible impact on car ownership at all.
Analysis from Glenn Mercer's excellent newsletter:
glennmercer.substack.com/p/the-impact...
Well, it turns out ridehail has no discernible impact on car ownership at all.
Analysis from Glenn Mercer's excellent newsletter:
glennmercer.substack.com/p/the-impact...
November 12, 2025 at 7:54 PM
Remember all the hype about how Uber and Lyft would allow people to live car-free?
Well, it turns out ridehail has no discernible impact on car ownership at all.
Analysis from Glenn Mercer's excellent newsletter:
glennmercer.substack.com/p/the-impact...
Well, it turns out ridehail has no discernible impact on car ownership at all.
Analysis from Glenn Mercer's excellent newsletter:
glennmercer.substack.com/p/the-impact...
Last week I gave a keynote about robotaxis' impact on urban life at the Smart City World Congress in Barcelona. For highlights, see here: www.linkedin.com/posts/david-...
TL;DR: European cities are already great. Adding robotaxis would bring significant risk -- and limited upside.
TL;DR: European cities are already great. Adding robotaxis would bring significant risk -- and limited upside.
November 12, 2025 at 6:00 PM
Last week I gave a keynote about robotaxis' impact on urban life at the Smart City World Congress in Barcelona. For highlights, see here: www.linkedin.com/posts/david-...
TL;DR: European cities are already great. Adding robotaxis would bring significant risk -- and limited upside.
TL;DR: European cities are already great. Adding robotaxis would bring significant risk -- and limited upside.
Reviewing Mamdani's past comments about transportation and getting pretty excited
www.reddit.com/r/Micromobil...
www.reddit.com/r/Micromobil...
November 11, 2025 at 5:34 PM
Reviewing Mamdani's past comments about transportation and getting pretty excited
www.reddit.com/r/Micromobil...
www.reddit.com/r/Micromobil...
"This article should end here. Alas."
From "'Self-Driving' Means Self-Driving," a new law review article by Bryant Walker Smith.
papers.ssrn.com/sol3/papers....
From "'Self-Driving' Means Self-Driving," a new law review article by Bryant Walker Smith.
papers.ssrn.com/sol3/papers....
November 11, 2025 at 12:47 PM
"This article should end here. Alas."
From "'Self-Driving' Means Self-Driving," a new law review article by Bryant Walker Smith.
papers.ssrn.com/sol3/papers....
From "'Self-Driving' Means Self-Driving," a new law review article by Bryant Walker Smith.
papers.ssrn.com/sol3/papers....
New NBER research finds that in NYC alone, Uber and Lyft collect $300M annually by making it hard to comparison shop before booking a ride.
www.nber.org/papers/w34441
www.nber.org/papers/w34441
November 10, 2025 at 2:11 PM
New NBER research finds that in NYC alone, Uber and Lyft collect $300M annually by making it hard to comparison shop before booking a ride.
www.nber.org/papers/w34441
www.nber.org/papers/w34441
@bmj.com, a renowned health journal, slams car bloat:
"Cars are becoming steadily larger, [and] with this comes potential harms to health...Action is needed locally, nationally, and internationally to curb sales of new SUVs and to reduce their presence in urban areas."
www.bmj.com/content/391/...
"Cars are becoming steadily larger, [and] with this comes potential harms to health...Action is needed locally, nationally, and internationally to curb sales of new SUVs and to reduce their presence in urban areas."
www.bmj.com/content/391/...
November 8, 2025 at 1:09 PM
@bmj.com, a renowned health journal, slams car bloat:
"Cars are becoming steadily larger, [and] with this comes potential harms to health...Action is needed locally, nationally, and internationally to curb sales of new SUVs and to reduce their presence in urban areas."
www.bmj.com/content/391/...
"Cars are becoming steadily larger, [and] with this comes potential harms to health...Action is needed locally, nationally, and internationally to curb sales of new SUVs and to reduce their presence in urban areas."
www.bmj.com/content/391/...
“Unlike the car, the e-cargo bike afforded a unique sensitivity to the natural world and local environment [that] enabled parents to train their children in local geography and responsible mobility.”
www.tandfonline.com/eprint/RW2MT...
www.tandfonline.com/eprint/RW2MT...
November 4, 2025 at 10:58 PM
“Unlike the car, the e-cargo bike afforded a unique sensitivity to the natural world and local environment [that] enabled parents to train their children in local geography and responsible mobility.”
www.tandfonline.com/eprint/RW2MT...
www.tandfonline.com/eprint/RW2MT...
Is Barcelona the most bike-friendly city on the Mediterranean?
Nowhere else I’ve been comes even close.
Nowhere else I’ve been comes even close.
November 2, 2025 at 12:50 PM
Is Barcelona the most bike-friendly city on the Mediterranean?
Nowhere else I’ve been comes even close.
Nowhere else I’ve been comes even close.
November 1, 2025 at 5:29 PM
I just arrived in Barcelona. One of the first things I noticed (and love): So many public places to sit down!
Such a contrast with the hostile architecture that's widespread in US cities.
Such a contrast with the hostile architecture that's widespread in US cities.
November 1, 2025 at 5:23 PM
I just arrived in Barcelona. One of the first things I noticed (and love): So many public places to sit down!
Such a contrast with the hostile architecture that's widespread in US cities.
Such a contrast with the hostile architecture that's widespread in US cities.
Just left a meeting at Prague’s city hall, where this plaza out front was a parking lot until a few years ago.
October 31, 2025 at 3:30 PM
Just left a meeting at Prague’s city hall, where this plaza out front was a parking lot until a few years ago.
The iconic front page, published 50 years ago today.
I found a copy on eBay 15 years ago. It now hangs above my desk.
I found a copy on eBay 15 years ago. It now hangs above my desk.
October 30, 2025 at 1:13 PM
The iconic front page, published 50 years ago today.
I found a copy on eBay 15 years ago. It now hangs above my desk.
I found a copy on eBay 15 years ago. It now hangs above my desk.
If Elon Musk wasn't so politically polarizing, "[American ]Tesla sales between October 2022 and April 2025 would have been 67-83% higher."
www.nber.org/papers/w34413
www.nber.org/papers/w34413
October 29, 2025 at 10:27 AM
If Elon Musk wasn't so politically polarizing, "[American ]Tesla sales between October 2022 and April 2025 would have been 67-83% higher."
www.nber.org/papers/w34413
www.nber.org/papers/w34413
Trump wants to force East Asia and Europe to buy Detroit's goliaths like the F-150. Not gonna happen.
Convincing explainer from @mikesmitka.bsky.social:
smitka.substack.com/p/pickups-fo...
Convincing explainer from @mikesmitka.bsky.social:
smitka.substack.com/p/pickups-fo...
October 28, 2025 at 8:53 PM
Trump wants to force East Asia and Europe to buy Detroit's goliaths like the F-150. Not gonna happen.
Convincing explainer from @mikesmitka.bsky.social:
smitka.substack.com/p/pickups-fo...
Convincing explainer from @mikesmitka.bsky.social:
smitka.substack.com/p/pickups-fo...
Note: According to Liscow's research, the 26 states pursuing DOGE-like layoffs are likely to *increase* total spending, at least for infrastructure.
October 23, 2025 at 12:13 PM
Note: According to Liscow's research, the 26 states pursuing DOGE-like layoffs are likely to *increase* total spending, at least for infrastructure.
State DOTs are hobbled by a paucity of experienced engineers.
Fewer skilled engineers --> Higher project costs
Fewer skilled engineers --> Higher project costs
October 23, 2025 at 12:11 PM
State DOTs are hobbled by a paucity of experienced engineers.
Fewer skilled engineers --> Higher project costs
Fewer skilled engineers --> Higher project costs
US downtowns are covered with car parking.
According to this new study, off-street parking takes up:
🔹 20.5% of downtown Dallas
🔹 22.3% of downtown Los Angeles
🔹 31.7% of downtown Tulsa
According to this new study, off-street parking takes up:
🔹 20.5% of downtown Dallas
🔹 22.3% of downtown Los Angeles
🔹 31.7% of downtown Tulsa
October 21, 2025 at 12:25 PM
US downtowns are covered with car parking.
According to this new study, off-street parking takes up:
🔹 20.5% of downtown Dallas
🔹 22.3% of downtown Los Angeles
🔹 31.7% of downtown Tulsa
According to this new study, off-street parking takes up:
🔹 20.5% of downtown Dallas
🔹 22.3% of downtown Los Angeles
🔹 31.7% of downtown Tulsa
I’m heading to Barcelona to give a keynote on Nov 4 at Tomorrow.Mobility, organized by @eiturbanmobility.eu. My topic: How cities can prepare themselves for a deluge of self-driving cars.
LMK if you’ll be there – or if you have tips to explore Barcelona’s famous superblocks.
LMK if you’ll be there – or if you have tips to explore Barcelona’s famous superblocks.
October 20, 2025 at 12:21 PM
I’m heading to Barcelona to give a keynote on Nov 4 at Tomorrow.Mobility, organized by @eiturbanmobility.eu. My topic: How cities can prepare themselves for a deluge of self-driving cars.
LMK if you’ll be there – or if you have tips to explore Barcelona’s famous superblocks.
LMK if you’ll be there – or if you have tips to explore Barcelona’s famous superblocks.
Interesting job alert:
Program Director for the new Abundance Academic Network, hosted by the Social Science Research Council.
Social science PhD required. Comp is $120k-$130k/year.
job-boards.greenhouse.io/socialscienc...
Program Director for the new Abundance Academic Network, hosted by the Social Science Research Council.
Social science PhD required. Comp is $120k-$130k/year.
job-boards.greenhouse.io/socialscienc...
October 17, 2025 at 5:07 PM
Interesting job alert:
Program Director for the new Abundance Academic Network, hosted by the Social Science Research Council.
Social science PhD required. Comp is $120k-$130k/year.
job-boards.greenhouse.io/socialscienc...
Program Director for the new Abundance Academic Network, hosted by the Social Science Research Council.
Social science PhD required. Comp is $120k-$130k/year.
job-boards.greenhouse.io/socialscienc...
Is the phrase “War on Cars” counterproductive to the movement b/c it turns off potential supporters?
Doug and Sarah see the risk. But they won’t be changing their podcast name anytime soon.
Doug and Sarah see the risk. But they won’t be changing their podcast name anytime soon.
October 17, 2025 at 12:35 PM
Is the phrase “War on Cars” counterproductive to the movement b/c it turns off potential supporters?
Doug and Sarah see the risk. But they won’t be changing their podcast name anytime soon.
Doug and Sarah see the risk. But they won’t be changing their podcast name anytime soon.
Interestingly, Sarah and Doug agreed that talking about street safety isn't a good way to get people thinking about reducing cars' role in society.
Crash deaths are too scary. Better to focus on quality of life.
Crash deaths are too scary. Better to focus on quality of life.
October 17, 2025 at 12:34 PM
Interestingly, Sarah and Doug agreed that talking about street safety isn't a good way to get people thinking about reducing cars' role in society.
Crash deaths are too scary. Better to focus on quality of life.
Crash deaths are too scary. Better to focus on quality of life.