The federal limit of 55 mph was set by Nixon during the gasoline shortages due to OPEC supply control. Clinton repealed it, so some states went up to 70 mph. Today we might consider enforcing them to help reduce carbon consumption (and collision fatalities).
Heck, maybe it's time to go back to 55 as a federal limit. Last I checked, most vehicles on the road get dramatically better gas mileage at 55. Rather, it gets exponentially worse as speeds increase past 60ish due to wind resistance.
That data was true back then, but is it true now? This is a legitimate question. Cars have changed a lot since then. They're mostly plastic, more aerodynamic, and engines are more efficient. So is 55 still the average optimal?
Heck, maybe it's time to go back to 55 as a federal limit. Last I checked, most vehicles on the road get dramatically better gas mileage at 55. Rather, it gets exponentially worse as speeds increase past 60ish due to wind resistance.