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Things to Remember about Interstate Highway Driving

What You Must Know about Interstate Highway Driving

When you practice for your permit and the DMV written tests, you should pay special attention to information about driving on interstates and controlled-access highways. Questions about interstate highway driving are very likely to appear on your DMV written test, whether you are a first-time permit applicant or just taking a re-examination.

Unlike what most people think, driving on controlled-access highways is usually safer than driving on other highways. There are fewer places on an interstate that can cause crashes. As an example, crossings and intersections don’t exist. When accidents do happen, they are, however, often more severe, mainly because of the high speed.

That is why most States emphasize safe interstate highway driving in their driver’s manual and on the written DMV test.

Your Speed when Entering an Interstate Highway

You enter an interstate by using an entrance ramp and, very often, an acceleration lane. The purpose of the acceleration ramp is to help you get up to speed.

Interstate Speed - Driversprep.com

Let us take a look at this question, which is pretty common on tests:


What should your speed be when entering an interstate highway?

  A. Same as the interstate traffic.
  B. Same as the legal speed limit.
  C. Faster than the interstate traffic.
  D. Slower than the interstate traffic.


The correct answer is A. Your speed when entering an interstate highway should match the traffic flow, keeping in mind that you must not exceed the posted speed limit.

B is incorrect since the traffic is sometimes moving at a different speed. Weather, visibility, or other circumstances may force traffic to move well below the speed limit.

Looking for a Gap when Entering an Interstate Highway

While getting up to speed on the acceleration lane, check over your shoulder for a gap between vehicles in the lane you want to enter. Don’t assume that other drivers will move over and give you space to merge smoothly.

Interstate Highway Driving - Driversprep.com

Make sure your gap gives you a big enough space cushion. Your gap should be at least four seconds. Avoid merging into a gap that is too small. A small gap can quickly become even smaller.

When you see a gap, signal your lane change before merging.

If you don’t see a gap, slow down and wait. Remember that you must give traffic on the interstate the right of way. Trying to merge when there is no space is hazardous. You may force other drivers to take evasive actions and cause an accident.

You should also avoid driving to the end of the acceleration lane and stop – if possible. If you stop, you will find it harder to get up to interstate speed and merge smoothly.

Safe Speed on the Interstate

You should keep pace with other traffic on the interstate without exceeding the speed limits. Driving much slower than other traffic is dangerous. The chance of a crash is very high when the difference between your speed and the speed of other traffic is more than 15 mph.

Look at the following question:


You are driving on a freeway posted for 65 mph. Around you, traffic is traveling at 70 mph. What should your speed be?

  A. Faster than 70 mph.
  B. 70 mph to keep up with traffic.
  C. No faster than 65 mph.
  D. Between 65 and 70 mph.


The correct answer is C.

Even if traffic flow exceeds the speed limit, you shouldn’t! The speed limit is there for a reason. In poor conditions, you must drive slower than the speed limit (this is known as the basic speed law).

Safe Following Distance on the Interstate

Always keep a safe following distance to the vehicle ahead of you. Be alert for large vehicles and motorcycles. Increase your following distance when needed. If visibility is reduced or the pavement is wet, always double or triple your following distance. Remember that rear-end crashes are the most frequent on Interstate highways. Don’t be a tailgater!

You should also keep space cushions to the sides by driving in the middle of your lane and avoid driving in another driver’s blind spot.

Safe Passing on the Interstate

Keep in the right-hand lane unless you need to pass other vehicles. If another driver wants to merge in front of you, be courteous and fall back to let them enter your lane smoothly. Adjust speed and following distance as needed.

When you pass and overtake other vehicles, pass with caution. Always signal and check your blind spots before making lane changes. Avoid lingering beside the other car when you pass. Pass as quickly as possible, and always on the left-hand side. Before pulling back in, ensure you can see the front of the vehicle you pass in your rear-view mirror. Allow some extra space before pulling back in front of a large vehicle.

Important Reminders

The following are some more reminders for your written DMV test (questions that could show up on your exam):

  • You must NEVER back up on the interstate. Should you miss an exit, always continue to the next one.
  • NEVER park on the shoulder of an Interstate unless your vehicle breaks down or there is another emergency. In such a case, stop off the roadway and ensure others can see you. Turn on your emergency flashers, raise the hood/trunk, and use a white cloth to signal your emergency.
  • NEVER cross the median of an interstate highway unless there is an opening and signs tell you that crossing is allowed.
  • If you are driving long distances, take a break every two hours and whenever you feel drowsy. Fatigue is a real danger on interstate highways.

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11 Comments

  1. christopher charles smith January 30, 2019

    Lol….merging at the legal speed when traffic is traveling at higher speeds is ” rarely a problem ” …really?…and there is no “statistics” to back up his claim about driving at or near the speed limit when the flow is higher…ehh??….well living in Dallas or anywhere else for that matter…its called common sense.especially in Dallas where there is always a couple people doing 55 (in the middle or 3rd lane)while traffic is zooming all around them and I guess you never saw a truck riding someone’s ass because they cant get around them but they refuse to get over….like you suggested everyone does to help people merge never mind normal driving…you must have the best of luck….because people always “get over”…I mean Atlanta and Houston are the most friendliest of cities to live in while driving a car especially at rush hour….its called common sense and common courtesy and rules or not and statistics (that they dont keep anyway) or not….the self righteous and clueless drivers who refuse to flow with traffic cause accidents and at the very least gapers and acts of road rage as well as forcing extra lane changes that eventually cause problems…..as well as the truck on thier ass I mentioned….I appreciated your helpful hints …..but dont write or ” hold court” the same way you drive at 5pm on a Friday

    • Self-righteous and clueless drivers who speed are the ones causing accidents. Not the other way around.

      There is no evidence that merging at the legal speed (when traffic flow permits) is a problem. Feel free to share if you actually have a report that shows otherwise.

      Anyone who suggests that speeding is OK just because everyone else is speeding is simply a dangerous and ignorant driver.

      Fact remains, driving over the speed limit when entering is illegal and irresponsible – regardless of you personal views of the matter.

  2. Edwin Anderson May 19, 2016

    When entering an interstate, DMV says to do the speed the traffic is doing…..but don’t exceed the speed limit. If the traffic is doing over the posted speed limit….we do what the traffic is doing….but we’re not supposed to go over the posted speed limit. Contradictory there, folks.

    • This “contradiction” is rarely a problem in real life. In heavy traffic when finding a gap can be difficult, the flow of traffic is usually within the speed limit or slower. Should the flow of traffic exceed the speed limit, there are usually plenty of gaps, and other drivers tend to move over to the left to let you merge smoothly. So accelerating to (or near) the speed of traffic and at the same time staying within the posted limit is often no problem.

      • You clearly haven’t lived in Houston or Dallas, then. The flow of traffic is ALWAYS a minimum of 10-15 (or more!) of the posted speed limit, even with five lines of bumper-to-bumper traffic. Unless, of course, there is a wreck. Best way to get yourself killed is to do the speed limit. So, not so rare, as I’ve seen this in many other places, as well. Don’t believe me? Try I-10 E across Louisiana sometime.

      • Lived the last 10 years in Dallas. Use Dallas North Tollway, Central Expressway, and 121 on a regular basis. I never had any problem entering any of these and keeping the speed limit during rush hour or otherwise.

        There is no statistical support for your statement that driving at the speed limit will get you killed. And encouraging new drivers to speed up above the speed limit when entering a highway is simply irresponsible.

  3. tredariusfrance September 3, 2015

    its a good driving test

  4. aaftab July 30, 2015

    is great heaip

  5. Louise Wilensky July 12, 2015

    Shouldn’t you always pass other vehicles on the left-hand side? Isn’t the left lane the passing lane?

    • Yes, absolutely. You should pass on the left side whenever possible. Passing on the right is normally allowed on multi-lane highways, but other drivers may not always expect you to pass on their right-hand side.

      Unfortunately, the text originally said right-hand side – it is now corrected.

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