Tramways have significantly lower CO2 emissions than Bus Rapid Transit (BRT) systems, according to a study released by Alstom and Carbone 4, a consulting company specialized in climate-resilient and low-carbon strategy.

The study concluded that over a 30-year lifetime, a tramway system emits about 50 percent of the CO2 as a BRT system operated with diesel buses, and about 30 percent less CO2 than a BRT system operated with hybrid buses. The study examined both systems’ entire lifecycle, including construction, operation and maintenance of the two systems.

These findings identified trams as one of the greenest urban transportation modes due to its relatively low environmental impact when in operation. According to Alstom and Carbone 4 Associate Director Julien Blanc, tramways are part of the solution for a cleaner environment.

“Reducing greenhouse gas emissions from transportation is both a key issue and exciting challenge,” Blanc said. “It should be achieved through relevant urban planning, energy efficiency, clean energy, and of course modal shift.”

The company contributes to international negotiations on climate change by supporting the Paris Process on Mobility and Climate (PPMC) and will participate in PPMC’s Transport Day on Nov. 13 in Morocco, where its Citadis trams have been in use in two major cities since 2011.

Studies by the French Development Agency have shown that two tramway lines should lead to a CO2 emissions reduction of about 30,000 tons per year.