I wish I knew, lol. I've never met anyone who's paid less than $100/month for car insurance. For my brother though it's probably on account of him being 19, being at fault for an accident that totaled 2 cars, having a speeding ticket for going 25mph over the limit, a $40k+ truck, and car loans like this requiring a $500 deductible at the highest it can be set.

He's not the best candidate for an insurance policy...

I would guess one difference is that the average distance traveled by car each year is higher in the US. Google results suggest its roughly twice as much.

Car insurance in the UK is hugely competitive with many businesses losing money on new policies.

Not sure about the US market but this could be a factor?

Safer roads probably. Speaking to Americans it's like crashes are an everyday occurrence and everyone seems to have experience of one. Over here it's more likely someone goes there entire life without a single collision or insurance payout at all.

Also Americans tend to be more litigious which has its costs.

Because we have requirements for driving cars. Its not easy to get a driving license, ppl know how to drive.

In US its “hey have you seen a car in your life, here have those keys”

Young people in overspecced cars? https://www.youtube.com/watch?v=MgDoXu__KyM