According to records filed in the case, Achtemeier conspired with mechanics in garages and operators of truck fleets to disable the anti-pollution software installed on diesel trucks.
Coconspirators who wanted to disable their trucks’ pollution control hardware system—a process commonly known as “deleting”—sought Achtemeier’s help to trick the truck’s software into believing the emissions control systems were still functional, a process known as “tuning.”
Monitoring software on a deleted truck will detect that the pollution control hardware is not functioning and will prevent the truck from running. Achtemeier disabled the monitoring software on his client’s trucks by connecting to laptops he had provided to various coconspirators. Some of the coconspirators would pass the laptop on to others seeking to have the anti-pollution software disabled on their trucks. Once the laptop was hooked up to the truck’s onboard computer, Achtemeier could access it from his computer and tune the software designed to slow the truck if the pollution control device was missing or malfunctioning. Achtemeier could “tune” trucks remotely, which enabled him to maximize his environmental impact and personal profit.
Propane is way less energy dense per volume than diesel, so it isn’t feasible for long-haul trucking. CNG/LNG is more energy dense than propane, but still nowhere near that of diesel fuel, which is why you see it in busses and garbage trucks. I know a few massive fleets (UPS comes to mind) that use CNG for some of their local routes, but that is probably more for the “green” optics than anything else.
propane is like 3/4 density of petrol and gram per gram carries more energy (propane 0.58g/ml, petrol 0.7ish g/ml) it’s slightly greener because it contains more hydrogen so more energy per carbon emissions
LNG is cryogenic, has even lower density (0.41 to 0.5 g/ml depending on temperature) and CNG is less dense still depending on pressure