7.1 Speed Limits & the Dangers of Speeding
Key Takeaways
Unless posted otherwise, it is unreasonable to drive over 20 mph in a school zone, 30 mph in a thickly settled or business district, 40 mph outside one, and 50 mph on a highway outside one.
A thickly settled district is an area where buildings are fewer than 200 feet apart for a quarter mile or more.
The Massachusetts Turnpike has a 40 mph minimum speed, and the Boston Harbor tunnels have a 20 mph minimum.
Under the fundamental speed law you can be ticketed below the posted limit, for example at 40 mph in a heavy rainstorm on a 50 mph highway.
Pedestrians struck at 20 mph are seriously injured or killed 13 percent of the time, rising to 40 percent at 30 mph and 73 percent at 40 mph.
Speed is a factor in about one-third of all motor vehicle fatalities. Higher speed means you see less, stop later and lose control more easily, and your vehicle's safety equipment works less well. Speed matters most for people outside the car.
| Vehicle speed when striking a pedestrian | Pedestrians seriously injured or killed |
|---|---|
| 20 mph | 13 percent |
| 30 mph | 40 percent |
| 40 mph | 73 percent |
Speeding also costs you money: higher fuel use, fines and higher insurance premiums.
Rule 1: The Fundamental Speed Law
You must never travel so fast that it is not safe, even when the posted limit is higher. Base your speed on:
- Traffic conditions: how many vehicles there are and how fast they are going
- Road conditions: a rough or smooth surface, water, ice or snow, and road width
- Weather and visibility: rain, snow, ice, dust and wind
- Pedestrians and bicyclists: unprotected people are more likely to be killed in high-speed crashes
Important
The manual's example: driving 40 mph in a heavy rainstorm on a highway posted at 50 mph can get you a ticket for driving too fast. The posted limit assumes ideal conditions.
Rule 2: Never Exceed the Posted Limit
Most Massachusetts roads have posted limits, and they change as road types change.
| Road type | Typical posted limits |
|---|---|
| Limited-access highways (such as interstates) | 50 to 65 mph |
| Smaller highways | 55 mph or lower |
Minimum Speeds
| Location | Minimum |
|---|---|
| Massachusetts Turnpike | 40 mph |
| Boston Harbor tunnels (Callahan, Sumner, Ted Williams) | 20 mph |
Even without a posted minimum, police may order a driver who is slowing traffic off a state highway.
Rule 3: The Unposted Limits
When no other limit is posted, your speed is not reasonable and proper if you drive over:
| Area | Limit |
|---|---|
| School zone | 20 mph |
| Thickly settled or business district | 30 mph (25 mph where a community has adopted it) |
| Outside a thickly settled or business district | 40 mph |
| On a highway outside a thickly settled or business district | 50 mph |
The statute behind these figures, M.G.L. chapter 90, section 17, describes the 50 mph figure as applying to a divided highway. In all cases you must still slow down for special hazards involving pedestrians, other traffic, weather or road conditions.
What "Thickly Settled" Means
A thickly settled district is an area where buildings are fewer than 200 feet apart for a distance of a quarter mile or more. You will often see "THICKLY SETTLED" signs where this applies.
The 25 mph Local Option
Under M.G.L. chapter 90, section 17C, a city or town may adopt a 25 mph limit for thickly settled areas unless posted otherwise. Signs are posted at every entrance to communities that have adopted it.
School Zones
Roads near schools have a 20 mph limit, which can be posted in several ways: signs with flashing yellow lights, or limits that apply during certain hours. Watch for signs saying you are approaching or entering a school zone, and look for children crossing or riding bikes, safety patrols and crossing guards.
Other Speed Rules
- Passing never permits speeding. You may not exceed the limit while passing (Section 8.3).
- Work zones: speeding fines are doubled (Sections 5.1 and 7.4).
- Vulnerable road users: you must obey the speed limit while passing them (Section 10.1).
- Ice cream trucks: the speed statute also treats driving faster than 15 mph within one-tenth of a mile of a vending truck showing flashing amber lights as unreasonable.
Speed-Limit Exam Traps
| Claim | Correct rule |
|---|---|
| "No sign means 55 mph everywhere." | False: unposted limits are 20, 30, 40 or 50 mph depending on the area |
| "Under the posted limit is always legal." | False: the fundamental speed law can make a slower speed illegal |
| "The Turnpike has no minimum." | False: its minimum speed is 40 mph |
| "Thickly settled means any town center." | False: it means buildings fewer than 200 feet apart for a quarter mile or more |
How Speed and Penalties Connect
| Driver | Consequence of speeding convictions |
|---|---|
| Any driver | Fine ($105 minimum, plus $10 for each mph beyond 10 over) and an SDIP surcharge |
| Adult with 3 speeding violations in 12 months | 30-day suspension |
| Junior Operator, first offense | 90-day suspension, new permit exam, retraining and road test |
| Junior Operator, later offense | 1-year suspension |
Scenarios
- No signs on a street lined with houses about 100 feet apart for half a mile: it is thickly settled, so the limit is 30 mph, or 25 mph if the town adopted the local option and posted it at its entrances.
- Dense fog on Route 2 posted at 55: the fundamental speed law requires a slower, safe speed, and 55 may be illegal.
- Driving 35 mph on the Turnpike in light traffic: below the 40 mph minimum.
Unless a different limit is posted, what is the maximum reasonable speed in a thickly settled or business district?
20 mph
35 mph
40 mph
30 mph
Which area meets the Massachusetts definition of a thickly settled district?
Buildings fewer than 500 feet apart for a distance of one mile or more
Buildings fewer than 200 feet apart for a quarter mile or more
Any area within one mile of a town hall or business center
Any road that has sidewalks and streetlights on both sides
You drive 40 mph in a heavy rainstorm on a highway posted at 50 mph. Can you be ticketed for speeding?
Only if you are also tailgating
Only on an interstate highway
No, because you are under the posted limit
Yes, under the fundamental speed law
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