My Response to David Zipper’s CityLab Article, “Don’t Shrink the Bus”

David’s article “Don’t Shrink the Bus”; read here

I recently read David Zipper’s article, “Don’t Shrink the Bus”, in Bloomberg CityLab, and I’m disappointed by how it oversimplifies critical nuances of mobility design. While David has made valuable contributions to urban mobility advocacy, this piece reveals a lack of understanding of the challenges and opportunities in designing future mobility systems, especially for the majority of Americans living in suburban or “thin” cities.

David and I crossed paths at a mobility conference over a year ago, where I gave him a copy of my book, Near to Far. After reading this article, I doubt he’s read it—if he had, he might have appreciated the critical differences between dense urban centers (“thick” cities) and sprawling suburbs, which are fundamental to discussing advanced mobility. Public transit may work well in New York City, but in thin cities, where over 200 million Americans live, it’s often slow, inconvenient, and underused. This is why only 2% of trips in the U.S. are taken on transit today. Any meaningful mobility solution must address this gap, yet David seems stuck in an urban-centric view that assumes large buses and trains are the only viable answers.

Misunderstanding Advanced Mobility Solutions

David begins by critiquing Tesla’s proposed autonomous “Cybercab” and Glydways, a company developing a Personal Rapid Transit (PRT) system. While he correctly notes PRT has faced challenges over the past 50 years, he conflates very different technologies: autonomous vehicles like Tesla’s Cybercab, which can navigate existing roads, and PRT systems like Glydways, which require dedicated guideways. This distinction matters because each technology serves a different purpose and addresses different needs.

For example, Glydways pods operate on narrow, closed tracks—akin to a “horizontal elevator.” These systems offer on-demand, nonstop service to a specific destination, bypassing the inefficiencies of buses that stop at every station. Glydways claims its system can move 9,000 people per hour in a lane the width of a narrow bike lane, compared to the 2,500 people per hour in a traditional much wider car lane. This scalability makes it a strong candidate for addressing mobility challenges in suburban areas, where large buses simply aren’t competitive with private cars.

David argues that small pods lack the efficiency of buses and trains, but he fails to acknowledge that the vast majority of Americans travel alone in cars with three or four empty seats. A transit system built around smaller vehicles designed for single riders or small groups could better match this travel reality while making transit more appealing to people who currently avoid buses altogether.

The Importance of Individualized Public Transit

David also overlooks a key issue that deters many Americans—particularly women—from using public transit: safety and privacy. Small, shared autonomous vehicles like Tesla’s Cybercab or Glydways pods offer riders the ability to travel alone or with chosen companions. This is a significant improvement over shared buses or trains, where interactions with strangers may feel unsafe or uncomfortable. If we’re serious about getting more people to use transit, we need to offer options that feel safe, convenient, and private. Individualized Public Transit, as I call it, addresses these concerns head-on.

David dismisses the potential of smaller, individualized systems to coexist with larger transit modes. But hybrid approaches—such as “dual-mode” systems where autonomous pods can travel on both streets and guideways—could unlock entirely new possibilities. Imagine a Glydways pod that picks you up at your home, travels on local roads, and seamlessly transitions onto a narrow elevated guideway to bypass traffic and reach your destination quickly. Such a system could blend the door-to-door convenience of a car with the efficiency of a transit network. David fails to even consider these creative possibilities.

The Role of Transfers in Transit Decline

David also ignores a long-standing barrier to transit adoption: transfers. Research shows that requiring just one transfer can cut transit ridership by 50%. Traditional buses and trains often rely on transfers to connect sprawling areas, making them less appealing to riders. Smaller, on-demand systems like Glydways could eliminate this problem by providing direct, point-to-point service without the need for transfers. This alone could be transformative in suburban areas where conventional transit struggles, as well in certain thick city areas.

Cost and Scalability Misconceptions

David argues that PRT systems require expensive infrastructure, such as tunnels and elevated tracks, making them less practical than buses. While it’s true that building guideways incurs upfront costs, these systems can be far more efficient over time because they don’t require human drivers, stop less frequently, and occupy much less physical space. Glydways’ narrow guideways, for instance, could be a far less intrusive and more cost-effective way to expand transit capacity than adding new lanes for cars or buses.

Moreover, David’s argument that large vehicles like buses are inherently more efficient overlooks their lack of scalability. A full bus is indeed efficient, but most buses outside dense cities operate far below capacity for much of the day. In contrast, smaller vehicles can better match real-time demand, improving both cost efficiency and rider experience.

A Missed Opportunity for Vision

What’s most frustrating about David’s article is its lack of imagination. Instead of exploring how innovative technologies like autonomous vehicles and PRT could complement one another, he dismisses them as impractical. For example, blending Tesla’s Cybercab concept with Glydways’ guideways could create a powerful hybrid system that delivers the best of both worlds: door-to-door convenience and congestion-free travel. This is the kind of bold thinking we need to solve mobility challenges in both thick and thin cities.

Conclusion

David Zipper is a thoughtful advocate for sustainable urban mobility, but his article misses the mark. By failing to consider the potential of small, individualized transit systems and their ability to complement traditional modes, he reinforces the status quo rather than challenging it. If we want to build a future where transit is competitive with private cars, we need to embrace innovative solutions that reflect how people actually travel. This means rethinking outdated ideas about buses and trains and exploring new systems that offer safety, privacy, and flexibility—especially in the vast suburban regions where transit has failed to gain traction.

The future of mobility is not “one-size-fits-all.” It’s a blended, multimodal system that uses the right tool for the right job. I hope David—and others—will start to imagine what’s truly possible.

Note: the key to making a viable dual-mode system as I described above, is successfully addressing both perceived and actual safety of the smaller autonomous vehicles | pods. In fact the system has to be far safer than today’s USA regional mobility systems, and can be. How? DM me and I will tell you how I would do it after focusing on very small cars in USA these past 40 years, and all new advanced micromobility network | system designs for the past 18 years :)