After a car accident, are you required to exchange infortmation?

I was involved in a car accident and called 911, police arrived seconds after my call with the dispatcher ended. The police officer separated each driver, filed an incident report and handed out a citation. They other driver drove away without providing me with any information whatsoever (name, license plate, phone number, car insurance etc). The police officer did not provide me with any of the other drivers information either. There was significant damage to both cars, though both cars were able to drive away. How can that be legal not just for the other to leave the scene but for the officer to let him go without the exchange of information occurring? Thank you.