Interstate driving

Key points

1. Use the merging or acceleration lane to speed up and merge with interstate traffic.

   Source: Handbook p. 68

   “You must use the merging or acceleration lane to speed up and merge with fast-moving traffic already on the interstate.”
   Tennessee Comprehensive Driver License Manual, Handbook p. 68

2. It is your responsibility to yield the right of way to cars already on the interstate.

   Source: Handbook p. 68

   “It is your responsibility to yield the right-of-way to other cars on the interstate.”
   Tennessee Comprehensive Driver License Manual, Handbook p. 68

3. If you cannot or do not wish to drive at or above the minimum speed, do not use the interstate.

   Source: Handbook p. 68

   “If you cannot or do not wish to drive at or above the minimum speed limit, do not use the interstate.”
   Tennessee Comprehensive Driver License Manual, Handbook p. 68

4. Stay at least 2 seconds behind, and at least 4 seconds in bad weather, at night and on fast rural sections.

   Source: Handbook p. 69

   “Stay at least two seconds behind vehicles in front of you, and increase this space to a minimum of four seconds in bad weather, night driving and on higher speed rural sections of the interstate.”
   Tennessee Comprehensive Driver License Manual, Handbook p. 69

5. The left lane is for passing only.

   Source: Handbook p. 69

   “Left lane is for passing only. • Courteous and safe driving practices require that drivers in”
   Tennessee Comprehensive Driver License Manual, Handbook p. 69

6. It is illegal to back up, make a U turn or cross the median on the interstate; if you miss your exit, go to the next one.

   Source: Handbook p. 70

   “It is also illegal to back up or make a U-turn on interstate highways. If you miss your exit, you must proceed to the next exit. It is illegal to cross the median on the interstate.”
   Tennessee Comprehensive Driver License Manual, Handbook p. 70

7. At a cloverleaf interchange, all turns are right turns.

   Source: Handbook p. 70

   “At a cloverleaf interchange, all turns are right turns.”
   Tennessee Comprehensive Driver License Manual, Handbook p. 70

8. Take a break at least every 2 hours or about every 100 miles.

   Source: Handbook p. 71

   “Take a break and get out of the car at least every two hours, or every 100 miles or so.”
   Tennessee Comprehensive Driver License Manual, Handbook p. 71

9. Quit driving when you are drowsy; drowsiness is the first step in falling asleep.

   Source: Handbook p. 71

   “Quit driving when you are drowsy. Drowsiness is the first step in falling asleep.”
   Tennessee Comprehensive Driver License Manual, Handbook p. 71

10. On highways with 4 or more lanes and 2 going your way, yield the lane next to a stopped emergency, maintenance or recovery vehicle.

    Source: Handbook p. 72

    “Tennessee law requires that motorists yield the lane closest to any emergency, maintenance or recovery vehicle that is stopped on the shoulder of the roadway. This applies to interstates and any multi-lane highway (with four or more lanes) that has at least two lanes of traffic traveling in the same direction.”
    Tennessee Comprehensive Driver License Manual, Handbook p. 72

Numbers to know

3 questions from the Tennessee practice test

1. 1. On a Tennessee interstate, how far behind the vehicle ahead should you stay, and how does that change in bad weather or at night?

   1. At least one second, doubled in rain
   2. Exactly one car length per 10 mph
   3. At least two seconds, increased to a minimum of four seconds
   4. At least ten seconds at all times
   Show answer

   At least two seconds, increased to a minimum of four seconds. Tennessee measures following distance in time, not car lengths. Two seconds is the floor on the interstate in good conditions, and the manual raises it to at least four seconds in bad weather, at night and on the faster rural sections. One second leaves no room for reaction, the car length rule is an old habit the manual does not use, and ten seconds is more than traffic will tolerate. Count from the moment the vehicle ahead passes a fixed object; if you reach it before the count ends, drop back.

2. 2. What should a driver do after recognizing drowsiness while driving?

   1. Open a window and continue until the next town
   2. Drive faster to reach the destination sooner
   3. Quit driving and take a break
   4. Stare straight ahead to maintain concentration
   Show answer

   Quit driving and take a break. The manual identifies drowsiness as the first step toward falling asleep and advises drivers to quit driving when they are drowsy. A window, extra speed, or staring ahead cannot reliably restore alertness and may leave the vehicle moving while the driver loses awareness. The safer plan is to stop at a suitable location, get out, refresh yourself, and resume only after you are fit to drive.

3. 3. On a multi-lane highway, what should a driver do when approaching a stationary emergency vehicle with flashing lights?

   1. Keep the same speed in the lane next to it
   2. Stop in the lane beside the emergency vehicle regardless of traffic
   3. Change into a lane not adjacent to it when possible, or slow down if changing lanes is unsafe
   4. Pass the vehicle on the shoulder to create more space
   Show answer

   Change into a lane not adjacent to it when possible, or slow down if changing lanes is unsafe. Tennessee's Move Over Law calls for yielding the lane closest to a stationary emergency, maintenance, recovery, or other covered vehicle when the highway has the required multi-lane configuration. If safety and traffic allow, move into a lane that is not adjacent. If that change would be impossible or unsafe, use due caution, reduce speed, and maintain a safe speed for conditions. Holding speed beside the vehicle defeats the protective space the law is designed to create.

Source: the Tennessee Comprehensive Driver License Manual, Section B-5: Interstate Driving. This lesson is a plain English summary, not the law itself; where it differs, the manual and the statute govern. Last checked 2026-09-27.