Strevey states that although Manistee County does not have air quality problems, he sees environmental benefits from using propane. The riders appreciate the fact that the buses have clean exhaust. In March 1993, because of the pilot program success, Metro began operating a total of 42 buses on LNG and has continued to add to the fleet. Metro now has the largest fleet of LNG-fueled buses in the world. According to Larry Luttrell, who manages the alternate fuels program for Metro, program staff chose LNG because it suited Houston's particular operations.
Natural gas is readily available in Texas at very reasonable prices.
In fact, Larry says Metro's fuel costs for LNG and diesel buses are approximately the same. Natural gas in liquid form is more convenient than in gaseous form for Metro's large operation. Buses can be refueled with LNG in the same amount of time as with diesel. On the other hand, LNG must be stored at very low temperatures to maintain liquid form. As a result, Houston's buses have highly insulated, cryogenic fuel tanks that will keep the gas cold for 7 to 8 days.