CCDL Permit Prep

General Knowledge · page 5 of 19

General Knowledge questions 81–100

Part of the 376-question General Knowledge pool. Each answer cites the FMCSA CDL Manual or the federal rule it comes from.

Practise these as a timed set

  1. What is the 'danger zone' following distance formula recommended for CMV drivers at speeds over 40 mph?

    • AOne car length per 10 mph, regardless of vehicle length
    • B3 seconds regardless of speed
    • COne second for every 10 feet of vehicle length, plus one additional secondCorrect
    • D5 seconds at all highway speeds

    At speeds above 40 mph, add at least one additional second to the base following distance of one second per 10 feet of vehicle length. A 60-foot truck needs at least 7 seconds of following distance.

    FMCSA CDL Manual · Driving Safely · verified 2026-09-08

  2. Which of the following best describes a 'jackknife'?

    • AThe truck slides off the road to the right
    • BThe trailer swings out and forms an angle with the tractorCorrect
    • CThe steering axle locks up
    • DThe trailer disconnects from the tractor

    A jackknife occurs when the trailer swings outward relative to the tractor (like a folding knife blade), usually caused by the drive wheels locking up. Proper braking technique and ABS help prevent jackknifing.

    FMCSA CDL Manual · Driving Safely · verified 2026-09-08

  3. Black ice is most likely to form on which parts of the road?

    • ADownhill grades
    • BStraight highway sections
    • CBridges, overpasses, and shaded areasCorrect
    • DWide intersections

    Black ice forms first on bridges and overpasses (which lose heat from both above and below), and in shaded areas where sun does not melt ice. These areas may be frozen when the rest of the road is clear.

    FMCSA CDL Manual · Driving Safely · verified 2026-09-08

  4. A freight truck is not in a vehicle category listed in § 392.10. Under § 392.11, how must it approach a rail grade crossing?

    • AAccelerate if there is no gate
    • BRely only on whether a warning light is flashing
    • CUse a fixed 15 mph at every crossing
    • DSlow enough to stop before the nearest rail and establish that the course is clearCorrect

    The federal rule for other CMVs requires a stoppable approach and due caution to establish a clear course. It does not impose a universal fixed speed or an automatic stop at every crossing. Obey other applicable traffic rules too.

    49 CFR § 392.11 · 392.11 slowing and clear-course requirement · verified 2026-09-07

  5. When parking a CMV on a downhill grade, the wheels should be turned:

    • AToward the curbCorrect
    • BAway from the curb
    • CStraight ahead
    • DDepends on which side is facing the road

    When parking downhill, turn the front wheels toward the curb or shoulder. When parking uphill with a curb, turn the wheels away from the curb.

    FMCSA CDL Manual · Driving Safely · verified 2026-09-08

  6. What is the purpose of a CMV's emergency triangles (reflective triangles)?

    • ATo mark the CMV's blind spots for other drivers
    • BTo warn approaching traffic when the vehicle is disabled on the roadwayCorrect
    • CTo signal a lane change at night
    • DTo mark hazardous materials on the trailer

    Reflective triangles warn approaching traffic that a CMV is stopped or disabled. Placement and timing depend on the applicable federal rule, roadway, and conditions.

    49 CFR § 392.22 · Emergency signals; stopped commercial motor vehicles · verified 2026-09-08

  7. The Federal Bridge Formula limits the weight on any set of axles to prevent:

    • AFuel waste
    • BCargo from shifting
    • CBrake overheating
    • DRoad and bridge damage from concentrated weightCorrect

    The Federal Bridge Formula limits weight on axle groups to reduce concentrated loading and protect roads and bridges.

    FMCSA CDL Manual · Weight Distribution · verified 2026-09-08

  8. When making a wide right turn in a CMV, you should:

    • ABegin the turn before reaching the intersection
    • BKeep the rear of the trailer close to the curb to prevent vehicles from passing on the rightCorrect
    • CTurn as quickly as possible, without keeping the trailer's rear close to the curb
    • DSwing left before turning right

    When making a right turn, keep the rear of your trailer close to the curb. If you swing left first, vehicles may try to pass on your right and be struck by the trailer. Watch your mirrors throughout the turn.

    FMCSA CDL Manual · Driving Safely · verified 2026-09-08

  9. Under FMCSA Hours of Service rules, a property-carrying driver may drive a maximum of how many hours after 10 consecutive off-duty hours?

    • A11 hoursCorrect
    • B10 hours
    • C12 hours
    • D8 hours

    Property-carrying drivers may drive a maximum of 11 hours after taking 10 or more consecutive off-duty hours. This is the 11-Hour Driving Limit under FMCSA regulations.

    FMCSA CDL Manual · Hours of Service · verified 2026-09-08

  10. The 14-Hour Rule for property-carrying drivers means:

    • ADrivers must take a 14-hour break after any day of driving
    • BThe total shift including breaks cannot exceed 14 hours
    • CA driver may not drive beyond the 14th hour after coming on duty, regardless of how much time was spent drivingCorrect
    • DDrivers may work up to 14 hours without a rest break, ignoring the required 30-minute break within that window

    The 14-Hour Rule is a 'window' — once a driver comes on duty, they have 14 consecutive hours to complete their driving. Off-duty time during that window does not extend it.

    FMCSA CDL Manual · Hours of Service · verified 2026-09-08

  11. The 30-minute rest break rule requires property-carrying drivers to take a break after how many hours of driving time?

    • A10 hours
    • B6 hours
    • C8 hoursCorrect
    • D4 hours

    For drivers subject to this rule, 8 cumulative driving hours trigger a required interruption before more driving. A continuous 30-minute period without driving qualifies, including on-duty non-driving time. Shorter stops do not combine across driving periods to make one qualifying break.

    FMCSA Summary of Hours of Service Regulations · 30-Minute Driving Break · verified 2026-09-07

  12. A property-carrying driver uses the federal 60-hour/7-day rule. At which accumulated ON-DUTY threshold does this cycle rule first bar further driving?

    • A80 hours in 7 days
    • B70 hours in 7 days
    • C60 hours in 8 days
    • D60 hours in 7 daysCorrect

    Drivers using a 7-day schedule may not drive after accumulating 60 on-duty hours in 7 consecutive days. Drivers on 8-day schedules use the 70-hour/8-day rule.

    FMCSA Summary of Hours of Service Regulations · 60/70-Hour Limit · verified 2026-09-07

  13. What is the main hours-of-service function of an electronic logging device?

    • AAutomatically record driving time and hours of service for most CMV driversCorrect
    • BMonitor vehicle speed only
    • CTrack cargo weight at each stop along the route
    • DReplace the driver's physical logbook entirely

    FMCSA requires most CMV drivers to use an ELD that automatically records driving time based on the vehicle's engine, accurately tracking hours of service. ELDs replaced paper logbooks for most carriers.

    FMCSA CDL Manual · Hours of Service · verified 2026-09-08

  14. A short-haul driver exemption from ELD requirements applies when the driver:

    • AMakes deliveries only within one state, regardless of distance from the terminal
    • BHas been driving commercially for over 5 years
    • COperates a vehicle under 26,001 lbs GVWR
    • DOperates within a 150 air-mile radius and returns to their home terminal within 14 hoursCorrect

    Drivers who operate within a 150 air-mile radius of their home terminal and return within 14 hours each day may qualify for the short-haul exception from ELD and logbook requirements.

    FMCSA CDL Manual · Hours of Service · verified 2026-09-08

  15. What does 'on-duty time' include for HOS purposes?

    • AOnly time logged as driving in the ELD
    • BAll time working, including loading, unloading, fueling, and waiting at a shipperCorrect
    • CTime from first departure to last delivery
    • DOnly actual driving time, not loading or waiting time

    On-duty time includes ALL time working for a carrier: pre-trip inspections, loading/unloading, fueling, maintenance, waiting at a shipper or consignee, and all driving. It is not just driving time.

    FMCSA CDL Manual · Hours of Service · verified 2026-09-08

  16. After taking a 34-hour restart, a property-carrying driver:

    • AResets their 60/70-hour clock to zero and can start a fresh cycleCorrect
    • BMay drive for 11 hours without any break
    • CIs exempt from the 14-hour rule for the first day
    • DMust take an additional 10-hour break before driving

    At least 34 consecutive hours off duty can restart a property-carrying driver's 60/70-hour cycle. The former requirement for two overnight periods from 1 to 5 a.m. was removed. A restart does not waive the daily driving limit or the applicable driving-break rule.

    FMCSA Summary of Hours of Service Regulations · 60/70-Hour Limit · verified 2026-09-07

  17. What should a driver inspect on the tires during a pre-trip inspection?

    • ATire pressure, without measuring tread depth or checking for cuts
    • BTread depth on the steering axle
    • CTread depth, inflation, and no cuts or bulgesCorrect
    • DColor and age of the tire

    Inspect tires for: minimum tread depth (4/32" on steering axle; 2/32" on other axles), proper inflation (no flat or severely under-inflated tires), and no visible damage (cuts, bulges, exposed cords).

    FMCSA Commercial Driver's License Manual (2005 CDL Testing System) · Section 11.2.4: Tires · verified 2026-09-08

  18. During the vehicle inspection, steering wheel play of more than how much can make it hard to steer, per the CDL manual?

    • A10 degrees (about 2 inches at the rim of a 20-inch wheel)Correct
    • B1 degree (about 1/5 inch at the rim of a 20-inch wheel)
    • C30 degrees (about 5 inches at the rim of a 20-inch wheel)
    • D45 degrees (about 8 inches at the rim of a 20-inch wheel)

    The manual says steering wheel play of more than 10 degrees, about 2 inches at the rim of a 20-inch steering wheel, can make it hard to steer.

    FMCSA Commercial Driver License Manual (July 2014) · Section 2.1: Vehicle Inspection (steering) · verified 2026-09-29

  19. During a pre-trip inspection of an S-cam air brake with a manual slack adjuster, how should brake adjustment be checked?

    • ASimply pressing the brake pedal
    • BWith the parking brakes released and the wheels chocked, pull hard on the slack adjuster; more than about 1 inch of movement indicates it needs adjustmentCorrect
    • CChecking the brake fluid level, a hydraulic-system check that does not apply to air brakes
    • DListening for unusual sounds when braking

    FMCSA Section 5.3.2 says to chock the wheels, release the parking brakes, and pull hard on each reachable manual slack adjuster. More than about 1 inch of movement where the push rod attaches indicates that adjustment is needed; automatic adjusters still require inspection.

    FMCSA Commercial Driver's License Manual (2005 CDL Testing System) · Section 5.3.2: Check Slack Adjusters on S-cam Brakes · verified 2026-09-08

  20. Why is proper speed management especially critical for CMV drivers on downgrades?

    • AEngine braking removes the need to manage speed on a downgrade
    • BGravity continuously accelerates the vehicle, and brake fade can occur if brakes are over-usedCorrect
    • CHeavy trucks have better brakes than cars
    • DDowngrades are only dangerous in wet weather

    Heavy vehicles gain tremendous speed going downhill due to gravity. Overusing the service brakes causes heat buildup and brake fade. Use a low gear (engine braking) to control speed before beginning the descent.

    FMCSA Commercial Driver License Manual · Section 2.16: Mountain driving · verified 2026-09-08