Yesterday, my 01 Yota Highlander started shaking when driving 60+. The shaking worsens the higher in speed. I didn’t get the chance to take a look at it, before my boyfriend left in it…
You should check for loose lug nuts right away as a first step.
If the lug nuts are tight the tires would be the next thing to check (low, damaged, losing tread, etc.), followed by the suspension. I wouldn’t drive it until the problem is found.