Is it possible to get arrested for being on TOO much caffeine in the US? Or to get like a DUI/DWI?

If it impairs your ability to operate a motor vehicle - yes.

DUI and DWI just say you are impaired while operating a motor vehicle. It does not say that the impairment is due to alcohol.

Yes you can, regardless of the state. Driving impaired includes any substance that can impair your ability to drive, not just the usual suspects (i.e. alcohol, hard drugs, etc). Keep in mind the amount of caffeine needed to impair your motor skills enough to affect your driving would be near the same amount to induce a heart attack. Impairment from cold medication is more of a concern than caffeine.

If consuming an excessive amount of caffeine impairs one's ability to drive, absolutely. You can be arrested for impaired driving after taking cough syrup.

Any substance, legal or not, that impairs your ability to drive can lead to a charge of driving while impaired, so although it would be unlikely, it is certainly possible.

As a California state prosecutor I know that driving under the influence can extend to caffeine if it leads to reckless driving.

Yes it is possible. .... DUI = Driving Under (the) Influence

No, It's ILLogical.

NO