reading the comments so far, in the UK an LPG truck fitted with a 3-way cat converter can be used in sensitive areas. The other benefit of LPG is that the downtime is far less. However, there's no statistics to prove this. I've been looking for running cost comparisons of a like for like electric and IC (LPG) truck over the same period of time, undertaking the exact same tasks to see which is really the best to choose.
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