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Illinois CDL — General Knowledge practice

Traffic Laws

Speed limits, turning and signaling rules, headlight and seat-belt requirements, and the everyday laws every driver must follow.

Questions reviewed against the official Illinois driver handbook · July 7, 2026

11 questions · pass with 9 correct. You get instant feedback and an explanation after every answer.

Study questions with answers

11 sample Traffic Laws questions with the correct answer, a short explanation, and the official handbook reference. Read through them, then take the quiz above.

  1. 1. What must a driver do when a train is approaching so closely that it creates an immediate hazard?

    Correct answer: Stop before the crossing

    You must stop when an approaching train is plainly visible and in hazardous proximity to the crossing. Failing to stop is a grade-crossing violation with escalating penalties.

    Source: Illinois CDL Guide — Sec. 1.5, Railroad Crossings

  2. 2. A driver causes a crash while distracted by a phone. What consequence does Illinois law allow?

    Correct answer: Criminal penalties and possible jail time

    Beyond ordinary traffic penalties, a crash that results from distracted driving may expose the driver to criminal charges and possible jail time.

    Source: Illinois CDL Guide — Sec. 1.8, Electronic Devices

  3. 3. What speed should you observe when approaching and driving through a roadway work zone?

    Correct answer: The posted work-zone speed limit at all times

    Always observe the posted work-zone speed limit. Speeding traffic is the leading cause of injury and death in work zones.

    Source: Illinois CDL Guide — Sec. 2.6, Roadway Work Zones

  4. 4. What is the leading cause of injuries and deaths in roadway work zones?

    Correct answer: Speeding traffic

    Speeding traffic is the leading cause of injuries and deaths in work zones, which is why observing the reduced posted limit is so important.

    Source: Illinois CDL Guide — Sec. 2.6, Roadway Work Zones

  5. 5. You are approaching a railroad crossing and traffic ahead is backed up. What must you never do?

    Correct answer: Start across before there is room on the other side

    Never let traffic conditions trap you into stopping on the tracks. Wait until you are sure there is room to get all the way across before you start over the crossing.

    Source: Illinois CDL Guide — Sec. 2.15, Crossing the Tracks

  6. 6. Why are railroad crossings with steep approaches a special concern for long, low vehicles?

    Correct answer: The vehicle could hang up on the tracks

    A steep approach can cause a low unit to hang up on the tracks, leaving it stuck where a train could strike it. Know your vehicle's clearance before crossing such tracks.

    Source: Illinois CDL Guide — Sec. 2.15, Crossing the Tracks

  7. 7. For drivers who are not always required to stop at a railroad crossing, what must they do as they approach?

    Correct answer: Reduce speed and make sure no train is coming

    Even when a full stop is not required every time, these drivers must slow down and make sure the tracks are clear of any approaching train before crossing.

    Source: Illinois CDL Guide — Sec. 1.5, Railroad Crossings

  8. 8. Illinois allows hands-free phone use for commercial drivers only under what condition?

    Correct answer: For drivers over age 18

    Hands-free or Bluetooth technology is permitted for drivers over age 18, but even hands-free use is still a distraction, so pulling over to make a call is recommended.

    Source: Illinois CDL Guide — Sec. 1.8, Electronic Devices

  9. 9. At a railroad crossing with gates and flashing lights, what must you do when the gate is lowered?

    Correct answer: Stop and remain stopped until it is safe

    You must stop and stay stopped when a gate is down or a flagman signals a train's approach. Never drive around a lowered gate.

    Source: Illinois CDL Guide — Sec. 2.15, Railroad Crossings

  10. 10. Under Illinois law, what may a driver NOT do with a cellphone while operating a commercial vehicle?

    Correct answer: Use a hand-held phone or send text messages

    State law bans using a hand-held phone, texting, or using other communication devices while driving a commercial vehicle. A crash caused by distracted driving can bring criminal charges and jail time.

    Source: Illinois CDL Guide — Sec. 1.8, Electronic Devices

  11. 11. Why should you avoid shifting gears while crossing railroad tracks?

    Correct answer: You could stall or hesitate on the tracks

    Shifting on the tracks risks the vehicle stalling or hesitating right where a train could hit it. Choose a gear before the crossing and hold it all the way across.

    Source: Illinois CDL Guide — Sec. 2.15, Crossing the Tracks

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Every Illinois question is written from the official Illinois driver handbook and checked against its current edition. DMV Test Free is a free, independent study resource — not affiliated with any DMV or government agency. About DMV Test Free