CDL Driving Safely
What should a truck driver do about a tailgater?
Increase the following distance ahead of your commercial vehicle. The added space gives you more room to slow gradually, reducing the chance that the tailgater will strike you from behind.
Short answer
Open more space ahead and let the tailgater pass when safe.
Do not brake-check, flash brake lights as a trick, or make a sudden speed change. Keep your own movement predictable and use a safe opportunity to remove the conflict.
Why the space belongs in front
You cannot directly control the gap behind your vehicle. You can control how abruptly you may need to slow. A larger following distance gives you more time to recognize a hazard and reduce speed smoothly.
- Increase the space between your vehicle and the traffic ahead.
- Keep speed changes smooth and signal early.
- Avoid retaliatory or surprising braking.
- Let the following driver pass when conditions make that safe.
Official source
Check “Space Behind.”
Review the current California Commercial Driver Handbook, Section 2, then check the same topic in your state's current manual.