According to NGV America, a typical dedicated natural gas vehicle, or NGV, can reduce exhaust emissions of carbon monoxide by 70 percent, non-methane organic gas by 87 percent, nitrogen oxides by 87 percent and carbn dioxide by almost 20 percent below those of gasoline vehicles. [...] the Honda GX is currently the only domestic, factory-made CNG vehicle distributed in America. [...] McCullough said, there were simply not enough vehicles equipped for natural gas.