The age at which you may start to legally drive a car will vary from state to state or if you are not in the US, it will differ depending on the providence, territory or county. The average age at which US states allow for a teenager to drive is typically fifteen or sixteen. The youngest age in the US at which you can drive appears to be 14 years old in South Dakota who can apply for an instructional permit.
In Florida you can legally obtain a learner permit at 15, in Texas at 15 you can get a driver's permit and in California you can get a provisional permit at 15 1/2. You must be 16 or over to drive in New York State. Other states such as Kentucky, Missouri and New Hampshire also require you to be at least 16 years old.
To obtain a Massachusetts Junior Operator's license you must be 16 1/2. In New Jersey you must be 17 unless at 16 you enroll in a behind the wheel driving course in order to obtain a special student learner permit.
In Ontario, Canada you can apply for a G1 license if you are 16 years old. The driving age in the UK is 17 unless you have full disability allowance so that you can apply for a provisional license at age 16. Most European countries require a person to be at least 17 or 18 years old to drive a car.
Some states are now moving into and proposing Graduated Driver Licensing systems.
To find out what the law is for your state, contact your local department of motor vehicles.