Highway and rail infrastructure investments are the biggest non-defence public sector investment commitments a country makes, involving decisions that will affect the spatial form of cities, the quality of life of residents, and city growth rates, with benefits accruing over many decades. Such choices include whether to invest in rail transit systems in large cities rather than rely entirely on roads and highways, and whether, for highways, to emphasise radial versus ring roads. Advice from international agencies frequently differs, and there are few quantitative estimates of the benefits of different forms of investment. Some impacts of rail transit and highway investments on city growth, urban form (density of residents and “sprawl”), environmental outcomes, energy usage and land use patterns within cities have become subjects of strong empirical studies only of late, and then only for the USA. But given differences in income levels, city population densities, and the national pace of urbanisation, the effects of such investments in developing countries such as China may differ from the US. This research intends to study the impacts of urban highway and rail infrastructure investments on city population, employment, and GDP growth/ urban form including the spread of developed land by use/ environmental outcomes, and urban land use patterns across residential, commercial, mixed, and industrial categories, as well as higher versus lower order uses within categories. China presents an ideal case study for researching these questions as there is considerable variation across cities in the prevalence of highway and rail transit investment. Moreover, China provides a large set of major cities for assessment, allowing us to take advantage of considerable between-city variation in transport infrastructure construction by type. The increase from a 45% urbanised population today to 75% in 30 years means that China’s cities will require huge additional investments in transportation infrastructure to function. Our research will provide insights that can inform policy choices in China.