The US tops the charts for its involvement in the light-rail space, which in many respects is considered the most sustainable form of passenger transport. Light rail is considered to be an environmentally sustainable transit option thanks to its contribution to reducing air pollution, energy consumption and greenhouse gas emissions.
While walking and cycling are the most sustainable ways of getting around, light rail comes out on top among its high-occupancy passenger transport peers, which include rail, tram, bus and metro. Compared with buses especially, light rail can draw more people out of cars, releases no air pollution and, like heavy rail, obtains power from environmentally friendly sources such as electricity.
Since 2010, the US has seen 27 light-rail projects come to market for a total value of $35bn and length of 553km.
Light rail is also perceived to be particularly good in cutting other externalities beyond air pollution, including accidents, noise and congestion, water and soil pollution. While findings indicate that a light-rail presence affects environmental sustainability in varying degrees, they also show that it alone cannot significantly affect energy intensity, energy per capita, carbon dioxide (CO2) intensity and CO2 per capita.
Other factors, including light-rail transit ridership, come into play as they influence how light-rail transit affects the environmental sustainability in urban areas.
Light rail is often used as a flashy panacea in cities that have low public transport ridership, where the money would be better spent on improving the bus network incrementally (facilities at stops, frequencies, routings, better buses, better information, better ticketing, guarantees ride home promises, etc.) IN many cases BRT or BRT lite would be a better investment.
By all means LRT if there will be proven ridership, or as a spur to transport led development.
And forthcoming electric buses (and traditional trolleybuses) would reduce environmental impact, as a transitional step to LRT (e.g. electric BRT with battery or trolley)
In the UK, it has been shown that LRT will encourage people out of their cars when buses won’t. Buses are very flexible which is good , but in the minds of many, just shows a level of impermanence.