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Pennsylvania driving lesson · Space, Speed and Conditions

Speed limits, traffic flow and eco-driving

A 4-minute lesson from the Pennsylvania course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.

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Read time
4 minutes
Course unit
Space, Speed and Conditions
Checkpoint questions
6
Source pages
42, 43, 47, 48

No single speed is safe at all times. The posted limit is the maximum for ideal conditions; you must also weigh the road, visibility and the traffic around you. Driving too fast for conditions is the No. 1 reason 16- and 17-year-olds crash.

Know the rule

Posted speed limits show the maximum safe speed under ideal road, traffic and weather conditions.

Handbook p. 42 ↗
70 mph

The maximum speed limit in Pennsylvania

Handbook p. 43 ↗

Know the rule

On interstates the maximum limit is posted after each interchange; on other highways it's posted at about half-mile intervals.

Handbook p. 43 ↗
15 mph

School zone limit when the sign's lights are flashing or during the times shown

Handbook p. 43 ↗

Know the rule

Drive below the posted limit when the road is wet or slippery, you can't see well, or anything makes conditions less than perfect. You can be ticketed for driving too fast for conditions even while under the limit.

Handbook p. 43 ↗

Know the rule

Crashes often happen when drivers go faster or slower than others. Drive with the flow of traffic within the posted limit. Boxed in by a highway pack? Slowing by just 2 or 3 mph lets traffic clear out around you.

Handbook p. 47 ↗

Know the rule

Face one hazard at a time. With a bicyclist on your right and an oncoming car, slow down, let the car pass, then move left to pass the cyclist with at least 4 feet of space.

Handbook p. 48 ↗
Handle one traffic condition at a time
Handle only one traffic condition at a time

Know the rule

Watch for vehicles that can't keep up: some large trucks (often using flashers on long or steep upgrades), farm equipment and horse-drawn vehicles. Stay a safe distance back and don't honk to pass.

Handbook p. 48 ↗
Slow-moving vehicle emblem
Slow-moving vehicle emblem (orange triangle)

Know the rule

An orange triangle on the back of a farm tractor or horse-drawn vehicle means it's designed to operate at 25 mph or less.

Handbook p. 48 ↗

Eco-driving numbers

Eco-driving numbers
HabitEffect
Driving above 60 mphAbout 5% more fuel per extra 5 mph
Rapid starts and hard stopsCan raise fuel use 40% but cut time only 4%
Cruise control on flat highwaysAbout 7% average fuel savings
Air conditionerUse it when driving more than 40 mph
Warming upOnly 30 seconds needed, even on the coldest days
Handbook p. 43 ↗

Other money-saving habits

  • Avoid driving in the hottest part of the day
  • Use your vehicle's ECO setting if it has one; see a dealer if the OBD light comes on
  • Turn off the engine instead of idling; if you must idle, shift to neutral or park
  • Drive less: transit, bike, walk, carpool, and combine errands
Handbook p. 43 ↗

Put it into practice

It's raining lightly on a 55 mph highway and traffic is heavy. Driving 55 could still earn you a ticket for driving too fast for conditions. Slow down below the limit and add following distance.

Check your understanding

Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.

What does a posted speed limit indicate?
  1. The minimum legal speed
  2. The exact speed you must maintain
  3. Max safe speed in ideal conditions
  4. The safe speed regardless of weather

Answer: Max safe speed in ideal conditions

Posted speed limits reflect the maximum safe speed under ideal road, traffic, and weather conditions.

Handbook p. 42 ↗
What is the maximum speed limit allowed anywhere in Pennsylvania?
  1. 65 mph
  2. 75 mph
  3. 60 mph
  4. 70 mph

Answer: 70 mph

The maximum speed limit in Pennsylvania is 70 mph.

Handbook p. 43 ↗
Can you be ticketed for driving too fast for conditions even while under the posted speed limit?
  1. Yes, regardless of the posted limit
  2. No, staying under the limit is always legal
  3. Only if a police officer is following you
  4. Only at night

Answer: Yes, regardless of the posted limit

Even within the posted limit, driving too fast for conditions can still result in a citation.

Handbook p. 43 ↗
How much can reducing your speed by just a few mph do when you're boxed in by a pack of highway traffic?
  1. Nothing, only changing lanes helps
  2. Encourage the traffic around you to clear out, restoring your space cushion
  3. Cause a rear-end collision behind you
  4. It has no measurable effect

Answer: Encourage the traffic around you to clear out, restoring your space cushion

Slowing by 2-3 mph often lets the vehicles around you clear out and open space.

Handbook p. 47 ↗
What color triangle is displayed on the back of farm tractors and horse-drawn vehicles designed to operate at 25 mph or less?
  1. Yellow
  2. Red
  3. Blue
  4. Orange

Answer: Orange

An orange slow-moving-vehicle triangle marks equipment moving at 25 mph or less.

Handbook p. 48 ↗
You can be cited for driving too fast for conditions even if you are under the posted speed limit.
  1. True
  2. False

Answer: True

Speed limits assume ideal conditions; driving too fast for poor conditions is still a violation.

Handbook p. 43 ↗
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