As mentioned earlier, dedicated LNG-fueled trucks (like those that use Cummins Westport engines) are now available from the factory, they have a limited range because the LNG tanks hold less energy than their diesel equivalents. This implies that they also require that the trucks return to their yards to refuel because LNG is not readily available in North America. The alternative is use a diesel-LNG dual fuel system (like the natural gas EcoDiesel System) that supplements diesel fuel with LNG, and the typical substitution rate is very conservatively about 30%. That would mean that a truck with 200 gallons of diesel capacity would require an LNG tank holding about 60 DGE (Diesel Equivalent Gallons) or about 104 gallons of LNG. This would extend the range of the truck approximately 40-45%. Alternatively, if a truck had a pair of 120 gallon diesel tanks (26" x 52" each), the replacement of one diesel tank with a 72 gallon (26" x 52") LNG tank would result in slightly reduced range (~70% of 240 gallon range) but with a significantly lower cost per mile. These systems seamlessly revert back to 100% diesel operation when the natural gas tank reaches empty so running out of natural gas never leaves you stranded. Much higher substitution rates are possible because the EcoDiesel System is fully programmable but this requires chassis dynamometer tuning for optimization. The LNG tank (typically 26" in diameter) will add about $14,000 to the cost of a diesel-LNG conversion, with higher capacities costing very slightly more on account of the added material cost for the increase in length. Installation would add about $1000 to the cost of conversion so that the overall cost of converting any diesel truck to LNG would be less than $18,000 per truck.