The New Flyer Industries C40LF is the compressed natural gas (CNG) version of the popular Low Floor model. The first C40LFs, serials 15399-15402, were produced in 1994 for San Diego Metropolitan Transit System in San Diego, California. They were numbered 1301-1304. These units featured simpler, more angular fuel tank housings.[1] The next batch of C40LFs were sold to the Metropolitan Atlanta Rapid Transit Authority (MARTA) in Atlanta, Georgia in 1996. In addition to the facelift given to all Low Floor models, this batch was the first to receive the redesigned fuel tank housing that would be used on every batch built since then.

After the 2009 model year, New Flyer no longer offered the LF series of buses with the traditional style front and rear ends. In November 2009, New Flyer updated their website and removed the LF models from their lineup. The C40LF was replaced by the C40LFR, however four orders for the New York MTA were built between 2011 and 2013