Final answer:
For a driver under the age of 21, the BAC limit that would result in penalties is .02%, which is stricter compared to the legal limit for drivers over 21. This limit is in place to discourage underage drinking and promote road safety.
Step-by-step explanation:
In most countries, including the United States, it is illegal for drivers under the age of 21 to operate a vehicle with a blood alcohol concentration (BAC) above a certain limit. For drivers under 21, the BAC limit that would result in penalties is .02%. This is a stricter limit compared to the legal limit for drivers over the age of 21, which is typically .08%.
The purpose of this stricter limit is to discourage underage drinking and driving as well as promote safety on the roads. It takes into account the fact that young drivers generally have less experience and may be more prone to making mistakes while under the influence of alcohol.
It's important for young drivers to be aware of and adhere to the legal alcohol limit to ensure their own safety and the safety of others on the road.