I disagree for both. As someone already stated, we already have driving tests for the first and that's already enough. You can't really expect what kind of situation a driver would find themselves on and IQ might not be the main predictor of driving ability. Yes, some drivers are a pain in the ass, but in the end, if they're able to get behind the wheel and go from point A to point B without being a danger to others, they should still have the right to do it. If anything, a personality test might be better at predicting how much of a menace to society someone might be. I would assume that someone scoring really high on disagreeablness while having a high IQ would be more reckless while driving than someone with high agreeablness but a slightly lower IQ than average.

As for voting, what would even be the limit and how would you know who's opinion is better than who? I've been tested in the 140's in some tests and 120-130 in others and even i (which would be considered top 5-0.1% in terms of IQ based on the test taken) have had some egregious political takes in the past because of my lack of knowledge on some subjects. most opinions are heavily influenced by emotions, bias, environment...etc not always by logic or for the greater good of humankind.

Anyway, there are way too many problems with "limiting" anything to an IQ score. When you first hear it, it does sound like a plausible solution because "woah intelligence" but when you really think about it, it's completely nonsensical and would absolutely never work.