Translations

Code	Language		Translator	Run

Credits

Fu Kwun Hwang; Fremont Teng; Lawrence Wee

Briefing Document: Traffic Light Reaction Time Simulator

1. Overview

This document summarizes the "Traffic Light Reaction Time Simulator" a Javascript/HTML5 simulation applet designed to illustrate the concept of reaction time and its impact on driving safety. The simulation, developed by Fu Kwun Hwang, Fremont Teng, and Lawrence Wee from Open Educational Resources / Open Source Physics @ Singapore, aims to help users understand the relationship between reaction time, vehicle speed, and safe following distance.

2. Main Themes and Concepts

• Reaction Time (RT): The core concept is reaction time, defined as "the elapsed time between the presentation of a sensory stimulus and the subsequent behavioral response." In this context, the stimulus is the traffic light turning red, and the response is the driver hitting the brakes.
• Impact on Driving Safety: The simulation emphasizes that during the reaction time, the vehicle continues to travel at the same speed. This distance covered during the reaction time is critical in determining a safe following distance. "During that period of your reaction time, your car is still moving at the same HIGH speed! So, what is the minimum distance between the front of your car and the rear of the car before yours? Assume that both cars need the same distance to fully stopped, the minimum distance is the velocity of your car multiply by your reaction time."
• Safe Following Distance: The simulation highlights the calculation of minimum following distance: distance = velocity x reaction time. It visually represents this distance on the simulator output. "The distance between the RED and BLACK arrows is the minimum distance to keep."

3. Simulation Functionality

• Interactive Elements: The simulator allows users to:
• Set the initial velocity of the car using a slider bar.
• React to a changing traffic light (green to yellow to red) by clicking a "brake" button.
• Observe the car's movement and stopping distance.
• Visual Representation: The simulation uses visual cues to illustrate key moments:
• Arrows indicate the car's position when the light changes (green, yellow, red).
• Arrows indicate the car's position when the brake is applied and when the car comes to a complete stop.
• Data Output: The simulation displays the user's reaction time, brake time, and stopping distance. "Your reaction time, brake time/distance are all shown in the text field."
• Adjustable Parameters: Users can toggle options to adjust initial velocity and friction coefficient.

4. Pedagogical Value

• Learning Goals: The simulator is designed to help users understand reaction time and apply this understanding to calculate safe following distances.
• For Teachers: The resource provides instructions for teachers, outlining the simulation's features and how to use it effectively in the classroom.
• Accessibility: The simulation is available in Javascript/HTML5, making it accessible on a variety of devices.
• Interactive Learning: The simulation encourages active learning by requiring users to react to stimuli and observe the results.

5. Technical Details

• Platform: Javascript/HTML5 (EJS).
• Creators: Fu Kwun Hwang, Fremont Teng, Lawrence Wee.
• Open Educational Resource: The simulator is an open educational resource, encouraging sharing and adaptation under the Creative Commons Attribution-Share Alike 4.0 Singapore License.

6. Key Quotes

• "Reaction time (RT) is the elapsed time between the presentation of a sensory stimulus and the subsequent behavioral response."
• "During that period of your reaction time, your car is still moving at the same HIGH speed!"
• "The distance between the RED and BLACK arrows is the minimum distance to keep."

7. Conclusion

The "Traffic Light Reaction Time Simulator" is a valuable educational tool for demonstrating the concept of reaction time and its relevance to driving safety. Its interactive nature, visual representation, and adjustable parameters make it an effective way to engage learners and promote a deeper understanding of this important physics concept.

 

Reaction Time & Highway Safety: A Study Guide

Quiz

Answer the following questions in 2-3 sentences each.

1. What is reaction time, as defined in the provided text?
2. According to the simulation's learning goals, why is understanding reaction time important for drivers?
3. In the traffic light simulation, what visual cues indicate the car's position at different moments, such as when the red light turns on or when the driver hits the brake?
4. What does the distance between the red and black arrows represent in the simulation?
5. How can users adjust the initial conditions of the simulation?
6. What actions should a user take when the light changes from green to yellow in the simulation?
7. Besides reaction time, what other data does the simulation provide to the user?
8. What does toggling the tabbed panels allow you to change in the simulation?
9. What are the steps to start and use the simulation?
10. Besides the Javascript version, what other versions of this reaction time simulator exist and who were the contributors?

Quiz Answer Key

1. Reaction time is the elapsed time between the presentation of a sensory stimulus (like seeing a brake light or a traffic light change) and the subsequent behavioral response (like hitting the brakes). It's the delay between perceiving something and reacting to it.
2. Understanding reaction time is crucial for drivers because it directly impacts the minimum safe following distance. During the reaction time, the car continues to travel at the same speed, increasing the risk of a collision if the following distance is insufficient.
3. The simulation uses colored arrows to mark the car's position: green for when the green light starts, yellow for the yellow light, red for the red light, black for when the brake is hit, and blue for when the car is fully stopped.
4. The distance between the red and black arrows represents the minimum distance a driver should keep from the car in front to avoid a collision, considering their reaction time at that speed.
5. Users can adjust the initial velocity of the car using a slider bar. The simulation options also include toggling display and toggling the friction coefficient.
6. When the light changes from green to yellow, the user should prepare to press the stop (square) button. The yellow light is an indicator that the red light is coming soon, signaling the user to get ready to react.
7. In addition to reaction time, the simulation shows the brake time and the distance traveled during braking. This allows users to understand the full stopping distance required.
8. Toggling the tabbed panels allows you to change the display, the initial velocity and the friction coefficient.
9. To start the simulation, click the "Play" button. When the traffic light turns red, click the stop button to simulate braking. Observe the car stopping and read your reaction time from the graph.
10. Java versions of the reaction time simulator exist. These versions were created by Hwang Fu-Kwun and lookang.

Essay Questions

1. Discuss how the traffic light reaction time simulator could be used in driver's education programs to promote safer driving habits. What are the strengths and limitations of using a simulation for this purpose?
2. Analyze the factors that can influence a driver's reaction time. How might these factors impact the minimum safe following distance, and how could the simulation be adapted to account for these variables?
3. Compare and contrast the different versions of the reaction time simulator (Javascript and Java). What are the advantages and disadvantages of each platform for educational purposes?
4. Describe potential modifications or additions to the traffic light reaction time simulator that could enhance its educational value. How could the simulation be made more engaging or informative for users?
5. Explain the physics principles behind the traffic light reaction time simulator. How does the simulation demonstrate the relationship between reaction time, velocity, distance, and braking force?

Glossary of Key Terms

• Reaction Time (RT): The time elapsed between the presentation of a sensory stimulus and the initiation of a behavioral response.
• Kinematics: The branch of mechanics concerned with the motion of objects without reference to the forces that cause the motion.
• Simulation: A model or representation of a real-world process or system, used for experimentation and understanding.
• Initial Velocity: The speed and direction of an object at the start of its motion.
• Friction Coefficient: A dimensionless value that represents the ratio of the force of friction between two bodies and the force pressing them together.
• Brake Time: The time it takes for a vehicle to come to a complete stop after the brakes are applied.
• Brake Distance: The distance a vehicle travels from the point when the brakes are applied to when it comes to a complete stop.

Sample Learning Goals

Reaction time (RT) is the elapsed time between the presentation of a sensory stimulus and the subsequent behavioral response. Imagine that you are driving on the high way, and suddenly, you see the brake light of the car in front of you just turned on. You will of course try to hit the brakes  to slow down your car. But, there is a small time delay before you really do that and that is your reaction time. During that period of your reaction time, your car is still moving at the same HIGH speed! 
So, what is the minimum distance between the front of your car and the rear of the car before yours?  Assume that both cars need the same distance to fully stopped, the minimum distance is the velocity of your car multiply by your reaction time.                            

This javascript applet helps you to determine your own reaction time and therefore based on the formula, calculate the distance to keep between cars when you are on the highway.

Click on the Play button to start the red car which will move with an initial velocity selectable from the slider bar.
The traffic light will turn from green to yellow, then to red at a randomly generated time interval.
Click on the brake button when you see the red light turned on.

The green, yellow and red arrows indicate the car's position when the green, yellow and red light started turned on.

The black and blue arrows indicate the car's position when you hit the brake and the position when the car is fully stopped.
The distance between the RED and BLACK arrows is the minimum distance to keep.
Your reaction time, brake time/distance are all shown in the text field.
Drive safely!

For Teachers

Traffic Light Reaction Time Simulator Javascript Simulation Applet HTML5

Instructions

Tabbed Panel and Options

 

 

Running the Simulation using Buttons

Toggling Full Screen

Reset Button

Research

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Video

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 Version:

1.  https://sg.iwant2study.org/ospsg/index.php/656 Javascript version by Hwang Fu-Kwun, lookang and Fremont
2. http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2306. Java version by Hwang Fu-Kwun and lookang
3. http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=137 Java version by Hwang Fu-Kwun

Other Resources

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FAQ: Traffic Light Reaction Time Simulator

• What is reaction time, and why is it important in driving?
• Reaction time is the time it takes between when you perceive a stimulus (like a brake light turning on) and when you initiate a response (like hitting the brakes). In driving, even a short reaction time can result in a significant distance traveled before the car begins to slow down, highlighting the importance of maintaining a safe following distance.
• How does the Traffic Light Reaction Time Simulator work?
• The simulator presents a scenario where a car is moving, and a traffic light changes from green to yellow to red at random intervals. The user must click a "brake" button when they see the red light. The simulator then calculates and displays the user's reaction time and the distance traveled during that time, illustrating the relationship between reaction time, speed, and stopping distance.
• What factors can I adjust in the Traffic Light Reaction Time Simulator?
• The simulator allows you to adjust several factors, including the car's initial velocity and the friction coefficient.
• What do the arrows in the simulator represent?
• The arrows represent key positions in the simulation:
• Green arrow: Car position when the green light turned on.
• Yellow arrow: Car position when the yellow light turned on.
• Red arrow: Car position when the red light turned on.
• Black arrow: Car position when the brake was activated.
• Blue arrow: Car position when the car came to a complete stop.
• How does the simulator help determine a safe following distance?
• The simulator calculates the distance traveled during your reaction time, which is the minimum distance you should keep between cars. This is based on the principle that both cars need the same distance to fully stop, therefore, the distance between the red and black arrows is the minimum distance to keep.
• How do I use the controls in the simulator?
• The simulator has a "Play" button to start the simulation. During the simulation, the light will change from green to yellow. When the light changes to red, the "Stop" button is enabled, which you should click to simulate braking. The simulation displays your reaction time, brake time, and distance. A "Reset" button will reset the simulation.
• Can I use this simulator on different devices?
• Yes, the simulator is a Javascript/HTML5 applet, so it can be used in a webpage and double tapping toggles full screen.
• Is the Traffic Light Reaction Time Simulator open source and free to use?
• Yes, the Traffic Light Reaction Time Simulator is part of the Open Educational Resources / Open Source Physics @ Singapore project. It is licensed under the Creative Commons Attribution-Share Alike 4.0 Singapore License.