Highway driving, merging and breakdowns

Key points

1. On highways with 4 or more lanes, keep to the right unless you are passing slower traffic.

   Source: Handbook p. 37

   “On highways with a total of four or more lanes (two or more lanes in each direction), always keep to the right unless you are passing slower traffic”
   Missouri Driver Guide, Handbook p. 37

2. Use the ramp and acceleration lane to match the speed of highway traffic.

   Source: Handbook p. 39

   “Use the ramp and acceleration lane to increase your speed to match the speed of the vehicles on the highway.”
   Missouri Driver Guide, Handbook p. 39

3. If you miss your exit, do not stop, back up or try to turn around on the highway.

   Source: Handbook p. 39

   “If you miss your exit, DO NOT stop, back up, or try to turn around on the highway.”
   Missouri Driver Guide, Handbook p. 39

4. After passing a truck, wait until you see its cab in your rearview mirror before returning to the lane.

   Source: Handbook p. 29

   “After you pass, make sure you can see the cab of the truck in your rearview mirror before reentering the lane.”
   Missouri Driver Guide, Handbook p. 29

5. Avoid highway hypnosis by constantly moving your eyes and watching traffic and signs.

   Source: Handbook p. 40

   “You can avoid highway hypnosis by constantly moving your eyes and watching the traffic and highway signs around you.”
   Missouri Driver Guide, Handbook p. 40

6. Tired drivers can be as dangerous as intoxicated drivers.

   Source: Handbook p. 40

   “Tired drivers are a great danger to themselves, other drivers, and can be as dangerous as intoxicated drivers.”
   Missouri Driver Guide, Handbook p. 40

7. If your vehicle breaks down, get off the road if possible and turn on your emergency flashers.

   Source: Handbook p. 41

   “If at all possible, get your vehicle off the road and away from traffic. • Turn on your emergency flashers to show you are having trouble.”
   Missouri Driver Guide, Handbook p. 41

8. The cellular number to call in a highway emergency is *55.

   Source: Handbook p. 41

   “The cellular number to call in an emergency is *55.”
   Missouri Driver Guide, Handbook p. 41

9. Never stand in the roadway, and do not change a tire if it puts you in a traffic lane.

   Source: Handbook p. 41

   “Never stand in the roadway. Do not try to change a tire if it means you have to be in a traffic lane.”
   Missouri Driver Guide, Handbook p. 41

Numbers to know

3 questions from the Missouri practice test

1. 1. When entering a Missouri highway through an acceleration lane, what should the driver generally do?

   1. Stop at the lane's end even when traffic is moving freely
   2. Increase speed to match highway traffic and merge through an opening
   3. Enter at a much lower speed than highway traffic
   4. Force into traffic because highway drivers must always stop
   Show answer

   Increase speed to match highway traffic and merge through an opening. An acceleration lane gives an entering driver room to build speed until it matches traffic on the highway. The driver should signal, find an opening, and merge smoothly rather than stopping at the end under ordinary conditions. Highway traffic should provide room, but an entering vehicle still must yield and must not force its way in. Use the lane for acceleration, then merge only when the gap is adequate.

2. 2. What should a Missouri driver do after missing a highway exit?

   1. Stop and back up along the shoulder
   2. Make a U-turn across the highway
   3. Take the next exit and return to the missed exit
   4. Reverse through the exit gore
   Show answer

   Take the next exit and return to the missed exit. If an exit is missed, the safe response is to continue to the next exit and come back to the one that was missed. Stopping, backing up, or turning around on a highway creates a severe conflict with traffic traveling at high speed. The driver should accept the extra distance rather than recover the intended exit immediately. Watch signs early, but if the exit is gone, continue forward to the next safe route change.

3. 3. What is Missouri's recommended response when highway hypnosis makes a driver sleepy?

   1. Pull off the highway and stop at a rest area or service area
   2. Increase speed so the repetitive road ends sooner
   3. Keep driving while staring straight ahead to maintain focus
   4. Rely on loud music instead of taking a break
   Show answer

   Pull off the highway and stop at a rest area or service area. Highway hypnosis can make a driver sleepy and unaware of surrounding traffic. Missouri advises pulling off the highway when sleepiness appears, and taking a nap when the driver is really sleepy. Staring harder, increasing speed, or using loud music does not restore safe alertness and can shorten the time available to react. A concrete cue is a repetitive stretch of road combined with lost awareness of signs or traffic. Treat that feeling as a stopping signal, not as a reason to push farther.

Source: the Missouri Driver Guide, Chapter 6: Highway 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.