Speed limits and the dangers of speeding

Key points

1. About one third of all motor vehicle deaths involve speeding.

   Source: Handbook p. 78

   “About one-third of all motor vehicle fatalities involve speeding.”
   Massachusetts Driver's Manual, Handbook p. 78

2. A pedestrian hit at 20 mph has a 13% chance of serious injury or death; at 30 mph 40%, and at 40 mph 73%.

   Source: Handbook p. 78

   “At a speed of 20 mph, 13% of pedestrians are seriously injured or killed in a crash. At 30 mph, that increases to 40% and at 40 mph it increases to 73%.”
   Massachusetts Driver's Manual, Handbook p. 78

3. You must never travel so fast that it is not safe; that is the fundamental speed law.

   Source: Handbook p. 79

   “You must never travel so fast that it is not safe. That is the fundamental speed law.”
   Massachusetts Driver's Manual, Handbook p. 79

4. Unless posted, speeds over 20 mph in a school zone or over 30 mph in a thickly settled or business district are not reasonable.

   Source: Handbook p. 79

   “20 mph in a school zone • 30 mph in a thickly settled or business district (unless there are signs showing a 25 mph limit)”
   Massachusetts Driver's Manual, Handbook p. 79

5. Unless posted, speeds over 40 mph outside a thickly settled district, or 50 mph on a highway outside one, are not reasonable.

   Source: Handbook p. 79

   “40 mph outside a thickly settled or business district • 50 mph on a highway outside a thickly settled or business district”
   Massachusetts Driver's Manual, Handbook p. 79

6. A thickly settled district has buildings less than 200 feet apart for 1/4 mile or more.

   Source: Handbook p. 80

   “A “thickly settled district” is an area where buildings are fewer than 200 feet apart for a distance of 1/4 mile or more.”
   Massachusetts Driver's Manual, Handbook p. 80

7. You can be ticketed for driving 40 mph in a heavy rainstorm on a 50 mph highway.

   Source: Handbook p. 80

   “If you drive 40 mph in a heavy rainstorm on a highway with a speed limit of 50 mph, you can get a ticket for driving too fast.”
   Massachusetts Driver's Manual, Handbook p. 80

8. Limited access highways, like interstates, have limits of 50 to 65 mph.

   Source: Handbook p. 79

   “Limited-access highways, like interstate routes, have speed limits from 50 to 65 mph.”
   Massachusetts Driver's Manual, Handbook p. 79

9. There is a minimum speed of 40 mph on the Massachusetts Turnpike.

   Source: Handbook p. 79

   “There is a minimum speed of 40 mph on the Massachusetts Turnpike.”
   Massachusetts Driver's Manual, Handbook p. 79

Numbers to know

Recognize these signs

3 questions from the Massachusetts practice test

1. 1. Unless posted otherwise, above what speed is a Massachusetts driver's speed not reasonable and proper in a thickly settled or business district?

   1. 30 mph, unless signs show a 25 mph limit
   2. 40 mph
   3. 50 mph
   4. 20 mph
   Show answer

   30 mph, unless signs show a 25 mph limit. Massachusetts speed law works from a list of unposted defaults, and a thickly settled or business district sits at 30 mph. Some communities have adopted a 25 mph limit and post signs saying so, which is why the choice mentions that exception. Twenty is the school zone figure, forty applies outside a thickly settled district, and fifty is for highways outside those districts. Exceeding the default is treated as speeding even without a sign, and driving at the default in rain or heavy traffic can still be ticketed as unreasonable.

2. 2. Unless posted otherwise, what is the Massachusetts statutory speed threshold on a divided highway outside a thickly settled or business district?

   1. 40 mph
   2. 50 mph
   3. 30 mph
   4. 65 mph
   Show answer

   50 mph. The Massachusetts statutory threshold is 50 mph on a divided highway outside a thickly settled or business district, measured over at least one-quarter mile. An undivided highway outside those districts has a 40 mph threshold instead. The distinction is the divided roadway, not simply whether a road is called a highway. Posted limits take precedence, and speed must still be reasonable for the actual traffic, weather, and road conditions.

3. 3. Unless posted otherwise, what is the Massachusetts statutory speed threshold on an undivided highway outside a thickly settled or business district?

   1. 30 mph
   2. 50 mph
   3. 40 mph
   4. 55 mph
   Show answer

   40 mph. An unposted, undivided highway outside a thickly settled or business district has a 40 mph statutory threshold in Massachusetts, measured over at least one-quarter mile. The corresponding divided-highway threshold is 50 mph. Open country alone does not make an undivided road a 50 mph road. A posted speed limit controls where signs establish one, and drivers must slow further when rain, limited sight distance, or other conditions require it.

Source: the Massachusetts Driver's Manual, Chapter 4: Rules of the Road. 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.