Encouraging city dwellers to walk and bicycle instead of using cars would offer much greater public health benefits than increased used of low-emission vehicles, U.K. researchers have found.
The study compared the projected health effects in 2030 of alternative urban land transport scenarios for London, England, and Delhi, India: business-as-usual (no greenhouse gas reduction policies); motor vehicles with lower carbon emissions; increased walking and cycling (active travel) plus less motor vehicle traffic; and a combination of increased walking/cycling and low-emission vehicles.
useful links: transport rankings