Calgary CNG bus crash puts low-carbon transit safety in the spotlight

A deadly crash in Calgary has put compressed natural gas buses under scrutiny. Three people died when a transit bus hit several vehicles and rear-ended a parked CNG bus, causing an explosion. A low-carbon transportation expert says the roughly 958 CNG buses operating in Ontario, Alberta and B.C. are considered extremely safe, and that investigators need to determine what went wrong before drawing conclusions about the technology. Calgary Transit runs nearly 250 CNG buses, about 20 percent of its fleet, and plans to buy 150 more this year to replace diesel buses. The bus manufacturer, Nova Bus, says it is cooperating with the investigation. The crash will likely influence how transit agencies weigh CNG against battery-electric options, especially since the climate benefits of CNG depend on controlling methane leakage and keeping fuel systems intact in collisions.