Driving less can lower your car insurance quotes, but sometimes you will be required to significantly lower your mileage, and the discount won't make much difference. Some companies offer 6-14% off their auto insurance rates for drivers that go from 10,000 to 5,000 miles a year.
Specifically in California, the savings for low mileage drivers are a lot higher, due to the state laws that are encouraging it. According to recent California laws, auto insurance carriers have to confirm the estimated annual mileage per vehicle.