Really nice project. If you are thinking commercial you may want to look into IP issues to see if there are active patents (probably expired by now?) As far as design choices, based on my journeys in similar types of projects: (just my$.02, not a critique) USB will be a significant point of failure. The connector has voltage present and electrochemical activity will destroy the connector over time unless you can keep…
Their owners manual for their braking light bar lists Patent # 10,363,865, but I don't know if this applies 1 to 1.