[blessedwhiskers]

Trailers certainly spend more time sitting around than the trucks do during loading/unloading times, so if you put the panels on the trailer you would improve the ROI, although I’m not an expert on trucking and don’t know how long trailers tend to sit idle.

I suspect adding PV panels would have another issue, however, which is they’re frequently stacked on top of one another in shipping yards, etc. PV paneled trailers would likely not be stackable, and therefore containers would need to be repackaged for storage or transport outside trucking (IE a container ship wouldn’t be able to just drop a container on to a truck to ferry it, it’d need to be reloaded).