Since it's the States that do it and not the Federal government, no it isn't un-Constitutional. There is no Federal requirement that you purchase car insurance.
States have a long established and well litigated Power to require that certain licenses be obtained and insurance coverages acquired for many reasons.
The Feds, however, have no such Power.
L
So then the states can constitutionally force me to buy health insurance. Can the Feds make the States force the purchase of health insurance by withholding Medicare payments or some other coercion?