Who needs to be on my car insurance as a driver
Everyone who drives the car should be on your car insurance policy as a driver, as well as everyone that drives your car regularly should be on your car insurance as a driver.
Everyone that lives in your household should be listed on the car insurance policy as a driver or as an excluded driver(meaning a non driver). All household members have to be listed if they are over the age of 16 because they have access to the vehicle to use as transportation, even if they are not licensed they are of age and physically could operate the vehicle so they have to be listed as a non driver on the insurance policy until their driving status changes to an actual operator. You list them as excluded on the car insurance if they do not drive the car at all, or do not have a license which means that they have no coverage if they actually would drive your car and cause an accident.
Here is an excerpt from a carrier describing who should be listed on the car insurance policy;
“You must list yourself, your spouse and any person who drives any vehicle on this policy regardless of whether that person lives with you. Please include any relative who resides in your home, is of legal driving age or has a permit even if he or she doesn't drive any vehicles. Also, please include any child who lives away from home and drives a vehicle on this policy, even if only occasionally.”
Why must everyone that drives must be listed, not just the owner of the car?
Insurance pricing is based on your risk profile. The likelihood of you having a claim. As your likelihood increases or decreases then your insurance can increase or decrease.
If a driver you know is driving will severely impact the rate; young driver or driver with prior accidents and tickets. And materially withholding that information can result in legal action by the insurance carrier.
It is better to protect yourself and A. not let anyone drive your car or B. Add all drivers to your policy. That way you have a clear conscience on making sure your car is properly protected in any circumstance.