Pre-tripping a tractor-trailer involves conducting a thorough inspection of the vehicle before hitting the road. This is important to ensure that the vehicle is safe to operate and in compliance with regulations. Here is a step-by-step guide to pre-tripping a tractor-trailer: Check the Tires : Inspect the tires for proper inflation, wear, and damage. Make sure that there is enough tread and that the tires are not showing any signs of dry rot or cracking. Inspect the Brakes : Check the brake pads and rotors for wear and make sure that they are functioning properly. Ensure that the brake lines are not cracked or leaking. Check the Lights : Make sure that all of the lights on the vehicle are functioning properly, including the headlights, taillights, turn signals, and marker lights. Check the Mirrors : Ensure that all of the mirrors on the vehicle are clean, properly adjusted, and not cracked or broken. Check the Fuel and Oil Levels : Make sure that the fuel and oil levels are