Cities with forward-looking mobility systems have two big, primary goals: to expand access for all residents and to end the supremacy of single-occupancy vehicles (SOVs). When access is easy, convenient, and equitable, cities gain in wealth and the well-being of residents. And when most travel doesn’t mean one person traveling alone in a car, especially a gasoline-powered car, cities are less congested, less polluted, and less likely to perpetuate patterns that deny certain residents and neighborhoods access to jobs and other opportunities. These words—variously attributed to either Gustavo Petro or Enrique Peñalosa, both former mayors of Bogotá—are a veritable urban mobility proverb: “A developed country is not a place where the poor have cars. It’s where the rich use public transport.”

Imagine the gains in economic opportunity and social integration, healthier air, and travel time saved. But questions remain: Is it possible to achieve both economic growth and greater equity? To ensure people’s freedom of movement while working together to save the planet? To preserve a city’s character and plan for the future? Our research explored these choices.

The goals are lofty yet vital for the future well-being of cities. As a starting point for improving urban transportation and mobility, we have built the BCG Accessibility Index to measure mobility performance across cities and to provide a detailed view of the mobility patterns within a city’s borders. These insights can help leaders identify the issues unique to their city and implement the solutions most likely to yield greater wealth and health. In this article, we explain the index, the issues, and the initiatives that cities must undertake.