California CDL 驾照笔试模拟练习

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1. Before driving a commercial vehicle, a driver must perform:

• A pre-trip inspection ✓
• A tire rotation
• A fuel check only
• Nothing if the vehicle looks fine

解析： A pre-trip inspection is required before driving — check brakes, tires, lights, cargo securement, and fluid levels.

2. What is the minimum following distance for a commercial vehicle over 40 feet in good conditions?

• One second
• Two seconds
• At least three seconds ✓
• Five seconds

解析： For vehicles over 40 feet, use at least three seconds of following distance; add one second for adverse conditions.

3. When you see a low-pressure warning while driving with air brakes, you should:

• Continue driving and check later
• Stop and park as soon as safely possible ✓
• Speed up to build air pressure
• Release the parking brake

解析： If a low air pressure warning comes on, stop and park as soon as safely possible — the brakes may not work correctly below minimum pressure.

4. Cargo should be secured so that it:

• Can shift slightly on curves
• Cannot move or shift during transport ✓
• Is evenly piled above the trailer sides
• Only needs securing for long trips

解析： Cargo must be secured to prevent movement or shifting during transport — shifting cargo can cause a rollover or loss of control.

5. When driving a commercial vehicle, you should check your mirrors:

• Only when changing lanes
• Every 5-8 seconds, scanning mirrors and traffic ✓
• Once per mile
• Only at stops

解析： Scan mirrors every 5-8 seconds to maintain awareness of traffic around a large vehicle with significant blind spots.