4) Outlaw automatic transmissions?

I remember the "good old days" when it was legal to buy a car with a manual transmission anywhere in the US. Sometime ca. 1970 or so, the move to legislated emission limits led to the virtual outlawing of manual transmissions in California. The extreme lean mixtures used to lower emissions led to a tendency to violent "knock" if one "lugged" the engine, and rapid destruction of the engine was a main result.

Since an automatic transmission can be "profiled" so that it can't slow the engine down to the "hard knock" range, it immediately became completely impossible (and illegal since none were "certified") to purchase a new car in California with a manual transmission. Elsewhere in the US, manual transmissions became much less popular with the auto makers, and manual transmissions were "deprecated" in many areas.

There's still little (less) choice for buyers in the US, except to some extent in the "big hunkers" that are so popular here.

John