Driving without car insurance is illegal. If a driver is in an accident or pulled over by the police, one of the consequences of not having insurance includes receiving a fine. While the specific dollar amount of the fine varies from state to state, all states require that drivers carry valid car insurance. You might also have to deal with substantial court costs and other requirements imposed on you by the state.
If one driver causes an accident, the other driver must be compensated for the loss of their vehicle. Without insurance, the driver at fault is monetarily responsible for covering all of these and more. Also, the uninsured would be personally responsible for all their court costs in addition to paying for the other driver’s replacement vehicle, medical costs, and whatever else they ask for.