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Lesson 19 of 26 · Section 8: Managing Time and Space

Scanning, stopping distance and road conditions

Seeing hazards early and knowing your stopping distance let you choose a safe speed. Wet, snowy and icy roads call for much slower driving.

Topic
Safe driving
Key points
9
Numbers
6
Manual
Handbook pp. 8-2 to 8-8
What you must know

Key points

  1. An expert driver looks 20 to 30 seconds ahead.

    Source: Handbook p. 8-2
    “An expert driver tries to keep looking 20 to 30 seconds ahead.”
    Maine Driver's License Manual, Handbook p. 8-2

  2. Check your mirror for traffic behind you every 6 to 8 seconds.

    Source: Handbook p. 8-3
    “Check your mirror often for traffic behind you - every 6 to 8 seconds.”
    Maine Driver's License Manual, Handbook p. 8-3

  3. On a wet road slow down 5 to 10 mph; on packed snow slow to half speed; on ice slow to a crawl.

    Source: Handbook p. 8-6
    “Wet road: Slow down 5 to 10 mph. Packed snow: Slow down to half speed. Ice: Slow to a crawl.”
    Maine Driver's License Manual, Handbook p. 8-6

  4. Bridges and overpasses freeze first and dry out last.

    Source: Handbook p. 8-7
    “Be aware that bridges and overpasses tend to freeze first and dry out last.”
    Maine Driver's License Manual, Handbook p. 8-7

  5. The average driver's reaction time is three quarters of a second to 1 second, and perception time is about the same.

    Source: Handbook p. 8-7
    “The average driver has a reaction time of ¾ to 1 second.”
    Maine Driver's License Manual, Handbook p. 8-7

  6. At 50 mph on dry pavement with good brakes, braking alone takes about 158 feet.

    Source: Handbook p. 8-7
    “At 50 mph on dry pavement with good brakes, it can take about 158 feet.”
    Maine Driver's License Manual, Handbook p. 8-7

  7. Adding perception and reaction time nearly doubles that braking distance.

    Source: Handbook p. 8-7
    “Adding perception time and reaction time nearly doubles this distance.”
    Maine Driver's License Manual, Handbook p. 8-7

  8. Headlights let you see clearly only about 250 feet, so over about 50 mph on a dark road you are driving blind.

    Source: Handbook p. 8-8
    “Headlights will let you see clearly only about 250 feet ahead. Therefore, if you drive faster than about 50 mph on a dark road, you are really "driving blind."”
    Maine Driver's License Manual, Handbook p. 8-8

  9. Do not drive through large bodies of standing water; find another route.

    Source: Handbook p. 8-7
    “Do not drive through large bodies of standing water. If the roadway is flooded, find another route.”
    Maine Driver's License Manual, Handbook p. 8-7
Exact figures

Numbers to know

NumberWhat it meansManual
20 to 30 secondshow far ahead an expert driver looksHandbook p. 8-2
6 to 8 secondshow often to check the mirrorHandbook p. 8-3
5 to 10 mphhow much to slow on a wet roadHandbook p. 8-6
¾ to 1 secondaverage reaction timeHandbook p. 8-7
158 feet at 50 mphbraking distance on dry pavementHandbook p. 8-7
250 feet, 50 mphhow far headlights let you see, and the speed at which you outdrive themHandbook p. 8-8
Check yourself

3 questions from the Maine practice test

  1. 1. What is the average perception time for an alert driver, according to the Maine manual?

    1. Three quarters to one second
    2. Two to three seconds
    3. Four to five seconds
    4. One tenth of a second
    Show answer

    Three quarters to one second. The manual places an alert driver's average perception time at three quarters to one second. Perception time is the interval needed to recognize that a stop is necessary, before physical braking begins. The longer ranges overstate the stated average, while one tenth of a second understates the time available in real driving. This interval is one part of total stopping distance, which also includes reaction and braking distance. Keep extra space when speed, visibility, or attention is less favorable than the ideal conditions used for the estimate.

  2. 2. What braking distance does the Maine handbook give at 50 mph on dry pavement with good brakes?

    1. About 500 feet
    2. About 30 feet
    3. About 158 feet
    4. About 1,000 feet
    Show answer

    About 158 feet. At 50 mph on dry pavement with good brakes, braking alone can take about 158 feet, and that comes after perception and reaction time. Headlights let you see clearly only about 250 feet ahead, so at night you must drive slowly enough to stop within that distance. Give yourself extra following distance before reducing speed or turning, and add more on wet or icy pavement.

  3. 3. How far ahead do headlights let you see clearly, according to the Maine handbook?

    1. About one mile
    2. About 1,000 feet
    3. About 50 feet
    4. Only about 250 feet
    Show answer

    Only about 250 feet. Headlights will let you see clearly only about 250 feet ahead, so at night you must drive slowly enough to stop within that distance. Maine law requires headlights whenever visibility is too dim to see 1,000 feet ahead, whenever the wipers are in constant use, and when it begins to get dark. Use high beams only when no vehicle is approaching.

Next step

Practice this topic

Lock it in with safe driving questions from the free Maine practice test. Every answer comes with a plain English explanation.

Practice this topicAll 26 lessons

Source: the Maine Driver's License Manual, Section 8: Managing Time and Space. 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.

Reviewed by , CA DOI #4037122 · Last updated 2026-09-27