Speed Limits & Following Distance — District of Columbia
District of Columbia CDL practice test: 423 free practice questions (Based on the official driver handbook). The official format is not yet verified; check the official site before your test. Speed Limits & Following Distance: 12 questions.
Posted speed limits, school and construction zones, stopping and following distance.
This topic page is still being reviewed against the official handbook. Until review is finished it is hidden from search engines.
| Topic / Metric | Value |
|---|---|
| Topic | Speed Limits & Following Distance |
| License test | District of Columbia CDL permit (CLP) knowledge tests |
| Topic questions | 12 (3% of 423 total) |
| Review status | This topic page is still being reviewed against the official handbook. Until review is finished it is hidden from search engines. |
Official handbook
Not yet verified
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Questions (12)
1. When driving a combination rig, following distance should be:
- Decreased in poor weather.
- Shorter than when driving a single vehicle.
- About the same as when driving a single vehicle.
- Longer than when driving a single vehicle. ✓
Answer: D. Longer than when driving a single vehicle.
Following distance in a combination rig should be longer than when driving a single vehicle. The handbook says combination vehicles are usually heavier and longer than single commercial vehicles, so they need more skill and more following room. In the combination-vehicle section it tells you to follow far enough behind other vehicles using a time gap based on your vehicle's length, plus an extra second over 40 mph, and to allow lots of following distance so you can brake early. Because a combination rig is longer than a single vehicle, that length-based gap works out to a longer following distance, not a shorter or equal one.
2. How many seconds of following distance per every 10 feet of vehicle should you maintain when traveling more slowly than 40 mph?
- One second ✓
- Two seconds
- Three seconds
- Four seconds
Answer: A. One second
When you are traveling slower than 40 mph, keep one second of following distance for every 10 feet of vehicle length. The handbook states the space-ahead rule directly: at least one second for each 10 feet of vehicle length at speeds below 40 mph, and at higher speeds you add one more second. So a 40-foot vehicle needs 4 seconds under 40 mph, and a 60-foot rig needs 6 seconds, matching the examples given. The passages also explain the reason for the rule: space ahead is what lets you stop if traffic in front of you slows suddenly, and following too closely is the most common cause of rear-end crashes for large vehicles.
3. When driving on the expressway during the skills test, you should:
- Switch lanes frequently.
- Use your mirrors to check traffic as needed. ✓
- Drive on the left side of the lane.
- Drive above the posted speed limit.
Answer: B. Use your mirrors to check traffic as needed.
You should use your mirrors to check traffic as needed while driving on the expressway during the skills test. The handbook's expressway instructions tell you to check traffic and your mirrors thoroughly in all directions when you resume, and its general driving section calls for regular mirror checks to stay aware of traffic around you. That makes mirror use the expected habit during the on-road test. The same expressway section also says to merge smoothly and keep your vehicle centered in the proper lane, so the test is not asking you to wander in the lane or change lanes for no reason.
4. A driver should always:
- Stay in their lane.
- Have an emergency plan. ✓
- Stay in the left lane.
- Drive above the speed limit.
Answer: B. Have an emergency plan.
A driver should always have an emergency plan. The handbook says you should always be looking for hazards, because hazards can turn into emergencies. Spotting them early gives you time to think through what could happen and decide what you would do. It then says to be ready to act on those plans. That is exactly the idea behind always having an emergency plan: you are prepared, defensive, and better able to protect yourself and others.
5. If you are being tailgated, you should:
- Drive on the shoulder.
- Pull off the roadway.
- Drive faster.
- Allow the vehicle to pass. ✓
Answer: D. Allow the vehicle to pass.
If you are being tailgated, allow the vehicle to pass by holding a steady, low speed and leaving extra room in front of you so the tailgater can get around. The handbook lists specific responses for a tailgater: avoid quick changes by signaling early and slowing gradually, open up your following distance, and do not speed up. It notes that extra room ahead both reduces your need for sudden moves and makes it easier for the tailgater to get past you. So the goal is not to escape the tailgater but to make passing them easy and predictable. The handbook also warns against tricks like flashing brake lights or turning on taillights.
6. To prevent a trailer from rolling over, you should:
- Speed up when nearing a corner.
- Make sudden steering moves.
- Take on-ramps faster than the posted speed limit.
- Drive slowly around corners. ✓
Answer: D. Drive slowly around corners.
To prevent a trailer from rolling over, drive slowly around corners. The handbook says rollovers happen when you turn too fast. For trailers, it advises you to steer gently and go slowly around corners, ramps, off ramps, and curves. A speed that is safe for a straight truck or a single trailer may be too fast for doubles or triples. Slowing down around a corner reduces the chance that turning speed will tip the trailer. The passage ties rollover prevention directly to gentle steering and lower speed in turns.
7. Stopping distance can be affected by:
- Speed. ✓
- Engine oil.
- Time of day.
- Traffic.
Answer: A. Speed.
Stopping distance can be affected by speed. The handbook ties stopping distance to how fast you are going. Figure 2.11 shows that when you double your speed, braking distance becomes four times longer, and high speeds greatly increase stopping distances. It also says that slowing down reduces braking distance. So among these choices, speed is the factor that directly changes the distance your vehicle needs to stop.
8. Stopping distance can be affected by:
- Speed. ✓
- Sunshine.
- Time of day.
- Traffic.
Answer: A. Speed.
Speed affects stopping distance: the faster you drive, the longer the braking distance becomes. The handbook's stopping-distance section says that when speed goes up, braking distance grows, and it gives the example that doubling speed makes braking distance four times longer. It also says slowing down reduces braking distance. The stopping-distance formula adds perception, reaction, and braking distance, so the speed-related braking part is a direct factor. The handbook does not present sunshine or time of day as factors in stopping distance.
9. Avoid needing to make sudden lane changes by:
- Using your horn to encourage other drivers to move out of your lane.
- Only driving slower than the posted speed limit.
- Watching the road ahead while driving. ✓
- Pulling off the road and waiting when there is high traffic.
Answer: C. Watching the road ahead while driving.
10. A driver should always:
- Stay in the right lane.
- Have an emergency plan. ✓
- Stay in the left lane.
- Drive above the speed limit.
Answer: B. Have an emergency plan.
A driver should always have an emergency plan. The handbook tells drivers to always have a plan. It says you should keep looking for hazards because they may turn into emergencies. When you see a hazard, think about what emergencies could develop and decide what you would do. Then be ready to act on that plan. Doing this makes you a prepared, defensive driver and improves safety for you and others on the road.
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Last checked: 2026-10-17 · Verified from official source
Updated: · Based on the official driver handbook