First health: "Take a 50-year-old office worker who drives 4.5km to work every day, a distance that is easily manageable by bicycle. If he switches from driving to cycling for 90% of these trips, at the end of the first year he could have shed up to 5 kilos of adipose tissue and will enjoy a 20 to 40% reduction in the risk of premature death and a 30% reduction in the risk of type 2 diabetes. He will also have better mental health and improved fitness." (And if you think it will take longer, note that the average car speed in London is 11kph - for bicycles it is 10kph.)
But conversely, in the developing world, cycles (rather than walking) would reduce calorie consumption and thus improve health: "The lion's share of transport in Africa is in rural areas, on unpaved paths and tracks, carrying crops from the fields to the villages.... (70-80% by women) carrying headloads of crops, typically weighing 30kg or more over an average distance of about 5km... A 2m-wide unpaved bike trail would cost less than 10% of the cost of a 6m-wide rural road for motor vehicle use.... One study in the Makete District of Tanzania found that, whereas building a feeder road saved households 120 hours per year, investing in a bicycle saved the family 200 hours a year.... a 'before and after study' of subsidised bicycle provision in Uganda found a range of beneficial effects, including more frequent trips to market and health-care facilities and increased household income."
Second, there's the argument of quality of life. Cars and trucks destroy community life, removing people (particularly children) from the streets. And above all, there's climate change - cars simply cannot continue to rule.
This is a book every council planner, every councillor, should read. It's not without faults. The writing has a hasty feel, as does the editing - it sometimes harms its argument by quoting different figures for the same facts in different places and is extremely uneven in its treatment of units of measure; some parts of the text appear to fit rather awkwardly with the rest (no doubt cooperative writing isn't easy). Nevertheless, I can pretty much guarantee that if you read this, there'll be at least one gripping fact you'll continue to quote for years to come.