Why Your City Feels Built For Cars, Not People
A new book posits that physical space, rather than policy, is the primary constraint for urban transport. I speak to the authors to learn more.
- The average downtown in U.S. cities dedicates 60% of surface area to car infrastructure — roads, parking lots, and garages — versus just 10% for sidewalks and bike lanes, according to the book's analysis of 50 global cities.
- Barcelona's superblocks program, which restricts car access in clusters of nine blocks, has reduced traffic by 25% and increased pedestrian space by 70% in pilot areas, serving as a key case study for physical space reallocation.
- Tokyo achieves a modal share of 30% for bicycles and walking despite high density, largely due to narrow streets (often under 5 meters wide) that physically limit car speeds and parking availability.
- Houston, Texas, faces a spatial paradox: 40% of its downtown land is used for parking, yet average traffic speeds are below 10 mph during rush hour because the sheer number of lanes encourages more driving.
- The book's 'spatial index' tool ranks 50 cities on the ratio of car space to human space; cities scoring highest on walkability (Copenhagen, Amsterdam) show 2:1 ratios, while car-dependent cities (Phoenix, Dallas) exceed 8:1.
"We've boxed ourselves into a corner where the only way to move more people is to give more space to cars, which destroys the walkability that makes cities livable."
"You can't build a bike lane where there's a parking garage."
Frequently Asked Questions
A new book by urban planners argues that physical space constraints, not policy alone, are the primary reason. Cars require vast amounts of land for roads and parking, leaving minimal space for sidewalks, bike lanes, and public plazas. This spatial imbalance makes it difficult to retrofit cities for people without controversial changes.
The spatial constraint refers to the physical limitation of city land. In many downtowns, 60% or more of surface area is dedicated to automobiles — either moving or parked. This leaves less than 10% for pedestrian and cycling infrastructure, creating a self-perpetuating cycle of car dependency.
Authors suggest shrinking road widths, eliminating minimum parking requirements, and reallocating space to micro-mobility lanes and wider sidewalks. Examples like Barcelona's superblocks show that restricting car access in clusters reduces traffic and increases pedestrian space, though it often faces initial public resistance.
Houston, Phoenix, and Dallas rank among the most car-centric U.S. cities in the book's analysis, with a ratio of car space to human space exceeding 8:1. In contrast, Copenhagen and Amsterdam achieve ratios closer to 2:1 through bike-friendly policies and narrow streets.
The book acknowledges it is extremely difficult and expensive. Retrofitting sprawling suburbs often requires massive demolition and rebuilding, making the 15-minute city model more feasible in dense urban cores than in suburban areas. However, incremental changes like narrowing lanes and adding crosswalks can improve walkability over time.
The spatial index is a new metric developed by the authors to measure the ratio of car-dedicated surface area to human-centric space in 50 cities. It provides a quantitative basis for comparing urban design and for city planners to set targets for rebalancing space.
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Original source
www.forbes.com
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