Speed limits and minimum speeds

Key points

1. The speed limit is the maximum allowed in ideal conditions.

   Source: Handbook p. 50

   “The speed limit is the maximum allowable speed in ideal conditions.”
   Missouri Driver Guide, Handbook p. 50

2. You may not drive slower than 40 mph on interstate highways under normal conditions.

   Source: Handbook p. 50

   “You may not drive slower than 40 mph on interstate highways under normal roadway conditions.”
   Missouri Driver Guide, Handbook p. 50

3. Unless posted otherwise, the speed limit in any city, town or village is 25 mph.

   Source: Handbook p. 50

   “The speed limit in any city, town, or village is 25 mph, unless posted otherwise.”
   Missouri Driver Guide, Handbook p. 50

4. The maximum speed limit on Missouri interstate highways is 70 mph.

   Source: Handbook p. 50

   “There are more than 1,300 miles of interstate highways in Missouri. Their maximum speed limit is 70 mph.”
   Missouri Driver Guide, Handbook p. 50

5. Cities and towns may set their own speed limits.

   Source: Handbook p. 27

   “Cities and towns may have regulations to do the following: • Set speed limits;”
   Missouri Driver Guide, Handbook p. 27

6. You must obey a slower school zone limit when lights are flashing or children are present.

   Source: Handbook p. 30

   “You must obey a slower speed limit in a school zone when lights are flashing or children are present.”
   Missouri Driver Guide, Handbook p. 30

7. Even if a higher speed feels comfortable in fair weather, never exceed a curve's advisory speed in rain, snow or ice.

   Source: Handbook p. 47

   “Although you may feel comfortable driving at a higher speed in fair weather, you should never do so in rain, snow or icy conditions.”
   Missouri Driver Guide, Handbook p. 47

8. Driving so slowly that you block traffic is against the law, even where no minimum speed is posted.

   Source: Handbook p. 59

   “If there is no posted minimum speed, it is still against the law for you to drive so slowly that you block traffic.”
   Missouri Driver Guide, Handbook p. 59

Numbers to know

Recognize these signs

3 questions from the Missouri practice test

1. 1. What is the maximum speed limit on Missouri interstate highways when a lower limit is not posted?

   1. 70 mph
   2. 65 mph
   3. 55 mph
   4. 75 mph
   Show answer

   70 mph. Missouri interstates have a maximum limit of 70 mph unless a posted lower limit applies. The 65 mph choice confuses a possible posted restriction with the statewide maximum described for these highways. Urban interchanges and frequent entering or exiting traffic may lead to lower signs, so a driver must read the roadside posting rather than assume the maximum is always available. A useful cue is to separate the road category from the actual sign: interstate maximum means 70 mph, while a safety based posting controls when it is lower.

2. 2. Who may set a different speed limit within a Missouri city, town, or village?

   1. Only the federal government
   2. The local government, through an ordinance
   3. Only the Missouri Highway Patrol
   4. No authority may change the statewide limit
   Show answer

   The local government, through an ordinance. Missouri gives local governments a role in traffic control beyond state laws. A city, town, or village may set speed limits through its own ordinance, so a driver must read the posted sign instead of assuming the general statewide rule applies. The federal government does not set ordinary local street limits, and the Highway Patrol is not the only authority involved. As a practical cue, treat a municipal speed sign as legally binding even when it differs from a familiar number elsewhere in the state.

3. 3. When must a driver obey the slower speed limit in a Missouri school zone?

   1. Only after a school bus opens its doors
   2. When school-zone lights flash or children are present
   3. Only when a crossing guard is standing in the roadway
   4. Only between midnight and sunrise
   Show answer

   When school-zone lights flash or children are present. The school-zone rule is activated by either of two visible conditions: flashing school-zone lights or children being present. A bus, nighttime hours, or a crossing guard is not required before the reduced limit applies. Drivers should scan for both the posted school-zone sign and the people or signals that trigger extra caution. The useful cue is simple: flashing lights or children means slow to the lower school-zone speed and stay alert for sudden crossings.

Source: the Missouri Driver Guide, Chapter 7: Pavement Markings, Traffic Signs, and Signals. 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.