Transportation Secretary Elaine Chao has said that the US government is about to unveil its revisions to the Obama-era federal self-driving vehicle rules, which will lower barriers to entry and make it easier for companies to test vehicles on US roads. Details are scant, but this could prove a boost for upstart companies looking to upset the established automakers. Such a move would be counter to what one would expect from the Republican Party, which typically favors big business and lobbyists, rather than the smaller startups – although it’s worth pointing out that Tesla is now worth more than GM. The incumbent automakers have voiced dissatisfaction with the current rules, claiming that they are compelled to hand over too much…