If you bothered reading my comment you'll notice that after commenting about Massachusetts it goes on to say that "[it was] followed by Connecticut, while most other states enacted similar requirements between the 1930s and 1970s, with nearly all states now requiring coverage, except for New Hampshire.
That's not what the law says. It says you must either have insurance or you must post security in order to drive.
That means you have to post that much money - not just promise to pay.
First, you don't know what redlining is.
I've only heard the term applied to property insurance (generally homeowners) and does not refer to charging different premiums based on whatever criteria. Rather it refers to a refusal to insure properties in a particular area. While the insurance company's decision is generally based on bad loss experience in the area in question (i.e., lots of claims, high crime area, and so forth) often times those areas are found in the inner city and are largely populated by minorities. So people do jump to the incorrect conclusion that the decision was based on race, not loss experience.
That said, you are correct that auto insurance rates vary based on a number of criteria (
race and ethnicity are not among them - that's strictly illegal).
And since insurance companies are in the business of assuming risk the premiums they charge are based on the degree of risk associated with individual drivers. Premiums must be "adequate, not excessive, and not unfairly discriminatory". And the premiums charged for the different "categories" is based on actuarial models (i.e., hard statistics) - and the different rates for those categories has to be justifiable - in other words
"not unfairly discriminatory" - and since auto insurance premiums are regulated by the state in the US and by the province in Canada the insurance companies have to be able to support those different rates - in fact they generally have to file the actuarial support for those premiums (and insurance departments do employ their own actuaries so the department is capable of reading (and understanding) those filings.
Looking at some of the criteria:
1) address - obviously someone who lives in a major city (where there are a lot of cars) is more likely to be involved in an auto accident than someone who lives in the country where there are few other cars. And it matters how much they drive and where to - the individual who lives in the country but commutes into the city for work is at higher risk than the individual who rarely, if ever, comes into the city.
2) annual mileage - again, it clearly makes a difference if (i) your daily commute is 30 miles or (ii) you only drive short distances
3) driving record [how many at fault claims have you had and what type were they]
4) age - statistics prove that young drivers have more accidents (and more serious accidents) than older ones. That tends to reverse when you consider the "upper end" of the senior citizen bracket.
5) sex - again statistics show that men have more accidents than women.
6) marital status - again statistics do show that married individuals have fewer accidents than unmarried ones.
7) income - I'm not aware of any company that takes this into account
8) type of auto - this generally only affects first party coverages (collision and comprehensive - damage to your own vehicle). Obviously a more expensive car is going to cost more to repair or replace than the basic "econobox". Ditto the age of the vehicle matters. But these covers are generally optional and what car you buy is your decision. BTW, when I say they're optional that isn't always strictly true - if you're paying for the car via a bank loan for example your bank may require you to purchase those coverages.
Now - thing is, not all discrimination is unfair. We have separate washrooms for men and women. We have minimum drinking ages. We don't give drivers licenses to young children and we don't allow them to join the military. Fact is, many places have graduated licensing for young drivers - they can't drive after dark, there are limits on how many passengers they can have, and so forth - those restrictions are removed after they've been licensed (and had no accidents) for however many years the relevant licensing laws require (note that this can be used as a proxy for age since the expectation is that most people will get a drivers license as soon as they are old enough).
Believe me, I've spent too many hours (days actually) testifying, under oath, about this topic.
There are places that have introduced public auto insurance but they still use variants on the criteria I discussed above when determining premiums. [To digress for a moment, that does have one advantage - the plates for your car are tied to your insurance - no insurance, no license.]
Of course that runs up against
"Friedmans Law" which basically says "government costs twice".