Visible Pedestrian: Detection Distance by Clothing

An experiment in a dim space, such as the gym or a long hallway with the lights off: an observer with a flashlight plays the headlights of a car and records how far away they spot pedestrians wearing dark clothes, light clothes or a reflective vest. With the data, students work out the reaction margin each outfit provides.

How to play

1. Darken the space, mark distances every 2 m with cones out to 20 m and explain the experiment (3 min).
2. Three pedestrians, in a dark shirt, a light shirt and a reflective vest, walk slowly from 20 m away; the observer calls "I see you!" as each one appears, and the distance is recorded (8 min).
3. Repeat in three groups with new observers and pedestrians and record all the data on the sheet (6 min).
4. Calculation: at 30 mph a car covers about 44 feet per second; how many seconds of warning does each outfit give? (5 min).
5. Takeaways for daily life: lights and reflective gear when walking, biking or riding a scooter at night (3 min).

Rules

• Pedestrians walk slowly in a straight line down a path clear of obstacles.
• Never shine the flashlight in anyone's eyes.
• Students waiting their turn sit along the wall.
• Turn the lights on between rounds so everyone moves safely.

Variations

Adaptations

• Visual impairment: acts as a pedestrian or recorder and gets the results read aloud.
• Limited mobility: acts as observer or group calculator.
• Anxiety in the dark: does the activity with the emergency lights on or next to the teacher.

Learning goals

• Use data to test how clothing affects visibility at night.
• Relate speed, distance and reaction time.
• Build visibility habits for active travel.

Equipment for a class of 25

• reflective vests: 6
• flashlight: 3
• tape measure: 3
• cones: 12
• worksheets: 30

Teacher tip

If you can't darken the space well, do it first period in winter or borrow the AV room. Reflective vests can come from families' cars.

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