Speed, night driving and bad weather

Key points

1. The maximum speed limit in Pennsylvania is 70.

   Source: Handbook p. 39

   “The maximum speed limit in Pennsylvania is 70.”
   Pennsylvania Driver's Manual (PUB 95), Handbook p. 39

2. Besides the posted limit, consider road conditions, visibility and the flow of traffic when choosing a safe speed.

   Source: Handbook p. 38

   “In addition to the posted speed limit, you must consider road conditions, visibility conditions and the flow of other traffic in choosing a safe speed to drive.”
   Pennsylvania Driver's Manual (PUB 95), Handbook p. 38

3. Use headlights when you cannot see pedestrians or vehicles 1,000 feet ahead.

   Source: Handbook p. 40

   “When they cannot see pedestrians or vehicles on the highway for a distance of 1,000 feet ahead of the vehicle they are operating.”
   Pennsylvania Driver's Manual (PUB 95), Handbook p. 40

4. Use low beams within 500 feet of an oncoming vehicle and within 300 feet of a vehicle you follow.

   Source: Handbook p. 40

   “Pennsylvania law requires you use low beams whenever you are within 500 feet of an oncoming vehicle and when you are following a vehicle within 300 feet.”
   Pennsylvania Driver's Manual (PUB 95), Handbook p. 40

5. To avoid overdriving your headlights on a dark road at night, do not drive faster than 45 mph.

   Source: Handbook p. 40

   “To avoid overdriving your headlights on a dark road at night, you should not drive faster than 45 mph.”
   Pennsylvania Driver's Manual (PUB 95), Handbook p. 40

6. You must turn on headlights whenever your wipers run because of weather.

   Source: Handbook p. 43

   “requires motorists to turn on their headlights anytime their vehicles wipers are in continuous or intermittent use due to weather conditions.”
   Pennsylvania Driver's Manual (PUB 95), Handbook p. 43

7. Roads are very slippery in the first 10 to 15 minutes of a rainstorm.

   Source: Handbook p. 40

   “Pavements can become very slippery in the first 10 to 15 minutes of a rain storm.”
   Pennsylvania Driver's Manual (PUB 95), Handbook p. 40

8. You can hydroplane at speeds as low as 35 mph in water only 1/10 of an inch deep.

   Source: Handbook p. 41

   “You can hydroplane at speeds as low as 35 mph, when water is only 1/10 of an inch deep.”
   Pennsylvania Driver's Manual (PUB 95), Handbook p. 41

9. On wet roads, slow by 5 to 10 mph and increase following distance to five or six seconds.

   Source: Handbook p. 41

   “Reduce your speed by 5 to 10 mph on wet roads and increase your following distance to five (5) or six (6) seconds.”
   Pennsylvania Driver's Manual (PUB 95), Handbook p. 41

10. In fog, do not use your high beams; the light bounces back and creates glare.

    Source: Handbook p. 42

    “Do not use your high beams. They direct their light up and into the fog, which bounces the light back into your eyes”
    Pennsylvania Driver's Manual (PUB 95), Handbook p. 42

Numbers to know

3 questions from the Pennsylvania practice test

1. 1. On a wet Pennsylvania roadway, which speed and spacing adjustment is recommended?

   1. Maintain dry-road speed and shorten the gap
   2. Accelerate before the tires encounter water
   3. Reduce speed and increase following distance
   4. Use the shoulder to avoid slowing traffic
   Show answer

   Reduce speed and increase following distance. Wet pavement reduces the margin available for braking and steering, so the manual pairs a lower speed with more space behind the vehicle ahead. The choice to keep dry-road speed assumes traction remains unchanged, while shortening the gap leaves less time to respond. Acceleration near water can worsen a loss of grip, and the shoulder is not a routine travel lane. When rain begins, ease off the accelerator early, enlarge the time gap, and make turns and stops smoothly.

2. 2. At what speed and water depth can a vehicle hydroplane, according to the Pennsylvania manual?

   1. Only above 70 mph in deep water
   2. As low as 35 mph in water only one tenth of an inch deep
   3. Only above 55 mph
   4. Only in standing water over an inch deep
   Show answer

   As low as 35 mph in water only one tenth of an inch deep. You can hydroplane at speeds as low as 35 mph when water is only one tenth of an inch deep, because rain brings oil in the asphalt to the surface and the tires ride up on the film. Slow down in rain, avoid puddles, and if you hydroplane ease off the gas and steer straight until the tires grip again. Near 32 degrees a layer of water on ice is worse than ice alone.

3. 3. When must a Pennsylvania driver turn on headlights because of weather-related wiper use?

   1. Only when the wipers have been running for 30 minutes
   2. Only when high beams are selected
   3. Only when driving after sunset
   4. Whenever the vehicle's wipers are in continuous or intermittent use
   Show answer

   Whenever the vehicle's wipers are in continuous or intermittent use. Pennsylvania’s headlight and windshield-wiper rule links the two controls whenever weather requires continuous or intermittent wiper use. The driver must turn on headlights during that period, and daytime running lights alone are not enough because the tail lights must also be illuminated. Sunset is a separate trigger, not a waiting period, and high beams are not required. When rain or another weather condition starts the wipers, use the headlights at the same time and verify the rear lights are on.

Source: the Pennsylvania Driver's Manual (PUB 95), Chapter 3: Learning to Drive. 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.