Urban Growth and Transportation

We estimate the effects of major roads and public transit on the growth of major cities in the US between 1980 and 2000. We find that a 10% increase in a city’s stock of roads causes about a 2% increase in its population and employment and a small decrease in its share of poor households over this 20 year period. We also find that a 10% increase in a city’s stock of large buses causes about a 0.8% population increase and a small increase in the share of poor households over this period. To estimate these effects we rely on an instrumental variables estimation which uses a 1947 plan of the interstate highway system and an 1898 map of railroads as instruments for 1980 roads.