Final answer:
The person ultimately responsible for preventing you from driving after consuming drugs that can affect your driving abilities is yourself.
Step-by-step explanation:
The person ultimately responsible for preventing you from driving after consuming drugs that can affect your driving abilities is yourself. While the police and the government have laws and regulations in place to deter and punish driving under the influence, and friends can provide support and advice, ultimately, the decision to not drive after consuming drugs is your own responsibility.