A blueprint for handling this can be cribbed off of "just transition" plans for folks in fossil electrical generation (coal) [1] [2] who are going to be out of a job in the next 5-10 years. Looking back at history, the productivity gains from automated vehicles can be split with the firms operating these fleets with those being transitioned out (as happened with the invention of the cargo container and Longshoremen's unions [3]). Another resource that covers this topic (in part) is The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger [4].
[1] https://www.justtransitionfund.org/
[2] https://www.worldbank.org/en/news/feature/2021/11/03/for-a-j...
[3] https://www.tandfonline.com/doi/pdf/10.1080/21533369.1999.96...