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District of Columbia driving lesson · Highway & Roundabout Driving

Passing & lane changes on highways

A 3-minute lesson from the District of Columbia course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.

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Read time
3 minutes
Course unit
Highway & Roundabout Driving
Checkpoint questions
5
Source pages
30, 31, 42

At sustained highway speeds, quick movements can be fatal. Careful lane changes and passing, plus cooperation between drivers, keep everyone safe.

Know the rule

In DC it is legal to pass on the left or the right on an interstate, but slow-moving vehicles must stay in the right lane, so most passing should be on the left. You cannot pass on the shoulder.

Handbook p. 30 ↗

Know the rule

Safe passing depends on cooperation. Do not speed up when you are being passed.

Handbook p. 30 ↗

Know the rule

Do not return to the lane too soon after passing. You should see the headlights of the vehicle you passed in your rearview mirror before moving back.

Handbook p. 31 ↗

Before and during a lane change:

  • Always signal a lane change
  • Check your blind spots by glancing over your shoulder
  • Check the outside mirror or look over your shoulder toward the left or right rear
  • Never cruise in the blind spot of the vehicle ahead of you
Handbook p. 31 ↗

On roads with marked lanes:

  • Stay in one lane; never drive partly in one lane and partly in another
  • Move from one lane to another only when you can do so safely
  • Signal no less than 300 feet before changing lanes; sooner is better
  • Slower than traffic on a road with 2+ lanes your way? Move to and stay in the right lane
  • Vehicle stopped on the shoulder? Slow down and move to the left part of your lane or the next lane
Handbook p. 42 ↗
300 feet

Minimum distance to signal before changing lanes

Handbook p. 42 ↗

Put it into practice

You're in the center lane and want to move right. Signal at least 300 feet ahead, check the right mirror, glance over your right shoulder for anyone in your blind spot, then move over smoothly without slowing.

Check your understanding

Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.

On an interstate, where should slow-moving vehicles generally stay?
  1. In the center lane
  2. In the left lane
  3. In the right lane
  4. In whichever lane has the least traffic

Answer: In the right lane

Slower vehicles should stay in the right lane so most passing happens on the left.

Handbook p. 30 ↗
At how many feet before changing lanes on a marked-lane road should you generally signal, per the handbook?
  1. No less than 300 feet
  2. 50 feet
  3. 100 feet
  4. 500 feet

Answer: No less than 300 feet

You should signal your intent to change lanes no less than 300 feet before doing so; sooner is even better.

Handbook p. 42 ↗
What should you do if you see a vehicle stopped on the shoulder ahead while driving on a multi-lane highway?
  1. Speed up to pass it quickly
  2. Slow down and move away within your lane
  3. Flash your headlights at it
  4. Stop immediately behind it

Answer: Slow down and move away within your lane

Give a stopped shoulder vehicle room by slowing and shifting left within your lane or into the next lane.

Handbook p. 42 ↗
Before changing lanes on a highway, what should you check in addition to your mirrors?
  1. Your blind spot, over your shoulder
  2. Your speedometer
  3. The lane markings ahead
  4. Your rearview camera display

Answer: Your blind spot, over your shoulder

Check your outside mirror and glance over your shoulder toward the rear before changing lanes.

Handbook p. 31 ↗
Why should you avoid cruising in the blind spot of the vehicle ahead of you on the highway?
  1. It blocks the passing lane
  2. That driver may not be able to see you
  3. It is only a courtesy issue
  4. It cuts your view of road signs

Answer: That driver may not be able to see you

Cruising in another driver's blind spot means they can't see you, increasing the risk if they change lanes.

Handbook p. 31 ↗
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