Not sure if this is the right sub, but does anyone have any experience/knowledge of using cellular networks for private applications?

I'm working on a project with someone that involves collecting large amounts of data from vehicles spread out across 10-15miles or so. LTE would be ideal but the amount of data we'd be moving rules it out financially. Is it even legal to set up your own mini cellular network?

First test field will be in the UK but we're looking at one in the US as well.