CDL Doubles/Triples Endorsement Practice Exam 2026 – Complete Test Prep

A key safety measure when coupling trailers is using the tug test to confirm security. This test involves gently pulling forward after the connections have been made, allowing the driver to feel if the coupling is secure. It's essential because it ensures that both the pintle hitch and the safety chains are properly attached, preventing any accidental separation while the vehicle is in motion.

This practice reinforces the integrity of the coupling connection and provides peace of mind that the trailers will remain securely attached during transport. Conducting this test can be crucial, especially with doubles or triples configurations, where the risk of detachment could have severe consequences on safety and vehicle control.