In less than 6 monthes, the new 2010 heavy duty diesel buses and trucks sold in the U.S. will test to the same emission certification standards as those powered with natural gas while emitting less than half the particulate matter of the natural gas vehicles (based on CARB certification data). Moreover, they are significantly less expensive than clean diesel buses and trucks, not to mention the additional cost of natural gas infrastructure if you don’t already have access to one of the 750 public fueling stations.

Of course, to improve upon the new clean diesel vehicles, there is always consideration of heavy duty diesel hybrid buses, which based on studies by the National Renewable Energy Lab, are 43 percent more fuel efficient and have 42 percent less maintenance costs than a CNG powered bus. Counties and cities realize this, as evidenced by the fact that 77% of the 10 largest transit districts’ bus orders for 2008 were for diesel hybrids.