How can you know if you are in the blind spot of a large vehicle?

• It is by chance, you can never be sure.
• If you are driving behind a large vehicle and cannot see both of its side mirrors, you are too close.
  Explanation:

  "Large vehicles have blind spots. If you are driving behind a large vehicle and cannot see both of its side mirrors, you are too close."
• If you are driving behind a large vehicle and can see both of its side mirrors, you are too close.
• If you are driving behind a large vehicle and cannot see both of its sides, you are too close