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The 30-Minute City: A Review
The author describes the book as a fast read. He is right – it is written in a very straight-forward style, avoids jargon and as such, I think it would be enjoyed by practitioners, first-degree students and even those with just a general interest in transport planning and accessibility. This is the fifth book published by Network Design Lab in David Levinson’s Access series.
Much of the book describes ways in which a 30-minute city may be created; and as Levinson says, “we do not require autonomous vehicles, hyperloops, drones, trackless trams, micromobility, or multi-copters, even if we eventually see such things widely deployed”. After the introductory chapters, chapters 3 to 10 provide practical examples of how accessibility has been eroded and conversely, how it can be improved by interventions that can be copied from elsewhere.
I was particularly taken by Chapter 3 on Traffic Signals. Through a simple example, Levinson illustrates that in a typical urban environment pedestrians lose 25%–30% of their effective speed because of traffic signals that are coordinated for cars, reducing their accessibility to jobs and other opportunities in a 30-minute walk space by almost half. He also offers solutions that can be implemented immediately. Essential reading for all practising signal engineers!
Another excellent illustration is given in Chapter 8 on Interfaces. The design of a station can have a big impact on accessibility. Through another Sydney example, he explains how saving just 75 seconds entering and leaving a train station can improve accessibility by 8%, for example by increasing the number or relocation of entries and exits, or changing the interfacing with buses.
In his last Chapter Levinson makes a plea for a new profession, Urban Operations – people engaged in improving today’s city, not just planning for tomorrow, but optimising for the system as a whole, using resources on-hand. As he says: “we have enough problems today. We also have solutions available to us today and we don’t implement them”.
Levinson’s arguments around urban restoration and retrofitting deserve a space in all transport planning courses. He makes a strong case to always consider the era during which an urban area evolved when developing solutions to address currently experienced traffic problems. Levinson advocates to restore what worked at that time (such as trams in historic centres of the early twentieth century), but not to try and impose such solutions in locations that were built for the motorcar in the fifties and sixties. The latter can only be retrofitted, at a cost and not necessarily effectively. In terms of retrofitting, Levinson provides a telling example of the temporary land-banking in urban at grade parking lots and concludes wistfully that unfortunately, temporary is often indefinite.
I enjoyed this book for two reasons: As a dyed-in-the-wool, it challenged me to think differently about what transport planning and traffic engineering should really achieve. Secondly, Levinson peppers his text with memorable one-liners and inventive terms: who had heard of gradial before? Two noticeable examples that I might use myself:
Gradial, or the unreasonable network – Embedded infrastructure cannot adapt much to the world around it. But if it were optimal for the world in which it was designed, it is unlikely to be optimal as that world changes. The network, designed for a given technology, is very hard to adapt to a different technology. Instead, we expect the world to adapt to the infrastructure. And
There are many techniques for making the most popular mode, the automobile, greener. We need to think more about making the greenest modes much more popular.
As would be expected, the book finishes with an extensive and useful bibliography.