Cyclist Reaction-Time Simulator
A browser experiment that measures how quickly cyclists notice an overtaking bike, with and without a rear-approach warning light.
- Randomised trials, half with the warning light enabled and half without
- Adjustable speeds, detection distance and closing-speed threshold
- Detection events and reactions exported as CSV for analysis
What it is
A self-contained simulation for testing a rear-detection warning light for bicycles. A top-down scene shows your bike being overtaken from behind. The approaching bike stays invisible until it is alongside, so the only early cue is the warning light.
How it works
- Detection logic: the light turns on when the other bike is behind, within the detection distance, and closing faster than a threshold, the same rule a real radar or ultrasonic unit would use.
- Experiment design: each trial randomly enables or disables the light (50/50), and the participant presses Space as soon as they notice the overtake.
- Controls: sliders for your speed, the other bike’s speed, detection distance and closing-speed threshold.
- Data: every detection edge and reaction is logged and exported as CSV to compare reaction times with and without the light.
Tech
One HTML file with vanilla JavaScript and Canvas 2D, and no dependencies. The simulation runs on a
requestAnimationFrame loop with a clamped timestep so it behaves the same on any machine.