9.1 Speeding Dangers & Massachusetts Speed Limits

Manual Chapter 4, Rules of the Road, begins with speed because speeding is a main cause of crashes and Massachusetts enforces its speed laws strongly. Instructors should present the speed rules as three layers: the fundamental speed law, posted limits and the limits that apply when nothing is posted.

The Dangers of Speeding

• About one-third of all motor vehicle fatalities involve speeding.
• At higher speeds drivers see less well, cannot stop quickly and are more likely to lose control. Safety equipment also works less well.
• Reaction time uses up more ground at higher speeds before braking even begins (section 5.1).
• Speed is the leading threat to pedestrian safety:

Speeding also wastes fuel (section 14.4) and leads to fines and higher insurance premiums (section 7.1).

Layer 1: The Fundamental Speed Law

"You must never travel so fast that it is not safe." Whatever the posted limit, your speed must account for:

• 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, who are unprotected and more likely to be killed at high speed.

You must slow down for poor conditions or hazards even if the posted limit is higher. The Manual's example: driving 40 mph in a heavy rainstorm on a 50 mph highway can earn a ticket for driving too fast.

Layer 2: Posted Limits and Minimum Speeds

Never drive faster than the posted limit. All speed limits assume ideal conditions.

Minimum speeds also exist:

Even where no minimum is posted, a police officer may order a driver off a state highway for slowing traffic. Section 12.2 adds that drivers in the second lane of a multilane highway should not go below the minimum and hold up trucks and buses.

Layer 3: Limits When Nothing Is Posted

Unless a sign says otherwise, a speed above these figures is not reasonable and proper:

What is "thickly settled"?

A thickly settled district is an area where buildings are less than 200 feet apart for a distance of 1/4 mile or more. Students may not see a speed sign in these areas, so teach them to judge the density of buildings.

Municipal 25 mph limits

Some cities and towns have adopted a 25 mph thickly settled limit unless otherwise posted, under M.G.L. c. 90, s. 17C. Signs are posted at every entrance to these communities, so pay attention when crossing a town line.

School Zones

The speed limit near schools is 20 mph. It may be posted in several ways: on signs with flashing yellow lights, or for certain hours of the day. Watch for signs that you are approaching or entering a school zone, and for children crossing or biking, school safety patrols and crossing guards (section 10.2). School-zone signs are fluorescent yellow-green (section 9.3).

Junior Operators and Speed

Speed violations hit young drivers hardest. A JOL holder's first speeding conviction means a 90-day suspension, a new permit exam, Driver Attitudinal Retraining, a new road test and a $500 reinstatement fee (section 8.1). For adults, three speeding violations in 12 months bring a 30-day suspension.

Coaching Speed Judgment

• Speed sense. Have students state the applicable limit before you reach a sign: "thickly settled, so 30 unless posted, or 25 if this town has adopted it."
• Conditions over numbers. On a rainy lesson, ask: "The sign says 50. What's legal right now?" The answer is whatever is reasonable and proper.
• Pedestrian math. Use the 13/40/73 percent figures when explaining why residential and school-zone limits are low. The jump from 20 to 40 mph multiplies the chance of serious injury or death by more than five.