Can passenger railways curb road-traffic externalities? – Empirical evidence

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Can passenger railways curb road-traffic externalities? – Empirical evidence
Rafael Lalive, Simon Luechinger, Armin Schmutzler, 15 March 2013

Against a backdrop of road accidents, pollution and congestion, many governments subsidise railways with the aim of reducing such externalities. But do improvements in public transport work? This column argues that recent empirical evidence confirms our expectations and, moreover, that public-transport improvements offer good value for money.

Road accidents kill 1.2m people every year (WHO). Road transportation is the main source of local air pollutants such as nitrogen oxide and carbon monoxide. It contributes to noise and global air pollution, and it leads to congestion. Against this backdrop, many governments subsidise railways with the explicit aim of reducing road-traffic externalities. However, do improvements in public transport really curb road-traffic externalities? In this column, we discuss recent empirical evidence identifying positive effects of public-transport improvements.

Better public transport

Better public transport reduces traffic externalities if people use trains rather than cars, and if trains are less polluting than cars. Neither of these conditions needs to be fulfilled. Even if better public transport attracts more passengers, road transportation is not necessarily reduced. Rather, the improvements in public transport may create even more traffic. Although, on average, transporting a passenger by public transport generates less pollution than transporting a passenger by car, it is less clear whether additional trains lead to less pollution than the cars they replace. Therefore it is ultimately an empirical question as to whether public-transport improvements reduce road-traffic externalities.

Measuring the effects of public-transport improvements

How can we estimate the effects of public-transport improvements? The challenge is to isolate policy effects from underlying trends. This is not a trivial matter, since authorities spend more on railways in places where they expect more traffic and thus deteriorating road safety and environmental quality. Any positive effects of public-transport expansions may be obscured by adverse underlying trends. ......................(more)

The complete piece is at: http://www.voxeu.org/article/can-passenger-railways-curb-road-traffic-externalities-empirical-evidence