It is misleading to attribute too much credit to a single individual, even a president. There was a significant clash of social/political forces when Obama was in office. Off the top of my head I can think of the following major forces: War in Iraq & Afghanistan, Great Recession & Occupy, DREAMers, ACA, Gay marriage, Environmentalism / Inconvenient Truth, Global outsourcing & job loss, Tea Party & the rise of militant christian nationalism. That's the landscape in which progressive policy ambitions were compromised to death to avoid total gridlock.
It's also worth giving credit where it is due: those auto safety and emissions regulations achieved their goal... for regular cars. Unfortunately, Republicans insisted on exceptions for body-on-frame vehicles (trucks, vans, SUVs). In the years since, those types of vehicles have steadily become the most common in the US, because they are the most profitable for the auto industry.