Travel behaviour and CO2 emissions in urban and exurban London and New York

•CO2 transport emissions are measured from household travel surveys.77% of CO2 emissions in London are generated in the exurban area.•87% of CO2 emissions in New York are generated in the exurban area.•CO2 emissions targets are set only for the urban area, not for the entire region.•Taking into account population growth, even those CO2 emissions will not be met.•Carbon reduction policies have to be targeted at the outer regions of cities.

Car travel and associated greenhouse gas emissions per capita in London's outer region are more than double than the ones of its metropolitan area. In New York's outer region car travel is four times per capita than what it is in its urban area. The comparative analyses are based on the UK National Travel Survey and the US National Household Travel Survey. The population outside Greater London' Green Belt and New York's periphery has been growing relentlessly since the 1950s. The transport structure of the South East of England and the New York Tri-State area has been largely shaped around the private car. Measures that aim to meet CO2 emission targets will need address the nature of the cardependent developments of London's and New York's growing outer fringe. The paper compares the current travel structure of the outer regions of the two cities that are nearly exclusively moulded around the motorcar. Using specially commissioned spatial breakdowns of the respective household travel survey data, detailed travel behaviour is analysed for both the urban and exurban areas. The data illustrates the stark contrast in mobility of the urban and exurban areas of the cities. Through an analysis of current vehicle use, estimates of CO2 emissions are made using established average emission factors per vehicle in each region. In our study of London and New York regions the exurban areas produce the bulk of car-based CO2 emissions: 77% for the London region and 87% for the New York region. Furthermore, using existing population forecasts and estimates of future average CO2 emissions per vehicle, future levels of CO2 emissions from private vehicles are estimated. Our estimates show that the CO2 emission reduction targets that have been set will not be met by a large margin.