Margaret Thatcher once declared that "a man who, beyond the age of 26, finds himself on a bus can count himself a failure". Taras Grescoe is proud to be  in Thatcher's estimation, at least  a failure. Although he can drive, the Canadian author, who is in his mid-40s, has never owned a car. And he is not alone. Half the population of cities such as New York, Toronto and London do not own cars. Every day some 155 million people take the underground. And although being a straphanger in North America may be, as Grescoe shows, a "depressing experience" due to underfunding and bad planning, elsewhere public transport  particularly in cities  is enjoying a renaissance. The heyday of the car has passed.

In this passionately argued and important book, Grescoe takes the reader on a whistle-stop tour of world cities and their transport systems. He accuses the private car of destroying cities, turning streets into kill-zones for the vulnerable, polluting the air and burning up increasingly scarce fossil fuels. Although the scope of Straphanger is global, it clearly targets car-loving, gas-guzzling North America and the statistics he cites are truly shocking. In the US  "the most extravagantly motorised nation in the history of the world"  vehicles now outnumber drivers by five to four. Los Angeles, once hailed as an "autopia", is now the most congested city in the US with drivers wasting 72 hours a year stuck in traffic jams  Americans now spend nine years of their lives sitting in their cars, and the pollution they produce kills 30,000 US citizens each year.

But change is in the air. In 2009, the total number of cars in the US shrank. In its early days in office, the Obama administration conjured up visions of a new golden age of public transport, offering funding for ambitious rail and subway schemes. Streetcars, which used to be the main mode of public transport in American cities, are being reintroduced in such unlikely places as Houston and Denver and, in 2010, public transport use reached a 54-year high. In this suburban nation, people are also moving back into the cities. Recently released figures from the 2011 US census show that many of the largest cities are now growing faster than their suburbs, the first time this has happened in a century. This trend is being led by young Americans, many of whom are also choosing not to learn to drive but are instead relying on bicycles and public transport. Even New York's billionaire mayor, Michael Bloomberg, is now known as the "straphanger mayor", riding the subway a couple of times a week. Although, as Grescoe notes, he is taken to the subway stop by chauffeured SUV.

Surprisingly for a book about public transport, London is not one of the cities Grescoe visits. Indeed the city is only mentioned for its "criminally expensive" tube tickets, the failed experiment of privatisation in 2003 and the lack of air conditioning ("cruel and unusual punishment"). Today more than a billion passenger journeys a year are made on the London Underground, a figure equalled by the subway system of New York and the Paris Métro. Although Shanghai didn't open its first line until 1995, its rapidly expanding metro has now become the longest subway network in the world and Moscow's underground is one of the busiest, carrying nine million people a day, a figure matched only by Tokyo.

Grescoe stops off at all these cities. It was in Paris that Blaise Pascal invented modern urban public transport in 1662 with the "carosses à cinq sols", carriages that ran along five fixed routes in the city, although sadly only for the gentry. Today the Métro "is the most ingenious and efficient transit network ever built". Parisian subway trains have been using autopilot technology since the 1970s but now fully automatic trains are being introduced. Grescoe is impressed by Shanghai's subway. Yet above ground the people have swapped bikes for cars, as they embrace a consumerist lifestyle. The result is congestion and pollution: the air in the city's streets has become a health hazard. Moscow's roads are also choked: it is "traffic hell". But its palatial Metro, built in the 30s, is "designed to ennoble and uplift the long-suffering straphangers of the world". In the Russian capital it's the only way to travel. In Tokyo he visits Shinjuku, with some 3.5 million commuters passing through every day. In comparison, the busiest station in the US is New York's Penn Station which handles a paltry 600,000 commuters. Grescoe is right to marvel at the "fantastic clockwork" of Tokyo's transport system: it is "the world's best example of a transit metropolis  a city built, and now kept running, by its trains".

Enrique Peñalosa, former mayor of the Colombian capital Bogotá, which revolutionised its public transport with a bus rapid transit scheme, makes a powerful point to Grescoe: "I believe a city is more civilised not when it has highways but when a child on a tricycle is able to move about everywhere with ease and safety." In too many places multi-lane highways have sliced through the cityscape, destroying communities and creating barriers between districts. But the act of driving also fundamentally changes the way people use the city. Inside cars, people are insulated from the sights and sounds of the city and isolated from other citizens. By contrast, public transport is a democratic and a social experience. In Tokyo someone tells Grescoe: "To use public transport is to know how to cooperate with other people, how to behave in a public space."

Good public transport is essential to the success of any world city. Grescoe argues that North America has fallen far behind Asia in its public transport infrastructure, and it "will be paying the price, in terms of lost competitivity, for decades to come". This is a warning for every city. But even in North America a quiet revolution is taking place in the way people travel. And this is happening in cities everywhere, as people from Philadelphia (the city with the highest percentage of Americans who commute on foot) to Copenhagen ("the world's most bikeable city") realise that the car is no longer an indispensable part of urban life in the 21st century.

 PD Smith's City: A Guidebook for the Urban Age is published by Bloomsbury.