Minimum insurance coverage required under Tennessee law is $25,000 per person. Unfortunately, these limits are extremely low, and they may not be enough to cover your claim. Further, many drivers simply choose to violate the law and carry no auto insurance at all.
When either of these situations occur, your own insurance company can be required to make up the difference, provided, of course, that your own insurance limits are higher than those of the driver who is at fault in the accident. This is referred to as the uninsured/underinsured provisions of your policy.