Drag Tree: Reaction Trainer

Drag Tree Reaction Trainer is a practice start light for drag racing reaction time. Hold the launch pad to stage, watch the start light tree count down and release on green. Your reaction time is shown in thousandths of a second, including red lights as a negative value such as −0.023.

Practice trees

- Full tree (sportsman): three ambers 0.500 s apart, green 0.500 s after the last amber.
- Pro tree .400 and pro tree .500: all three ambers at once, then green.
- Pre-stage and stage bulbs, a random stage delay you can set, and an optional rollout delay.
- Release mode (hold, lift on green) or Tap mode.

Honest timing

- Reaction time = the touch event time minus the frame that actually drew the green light. Results are not rounded to screen frames, so you see a real spread of times, not the same few numbers.
- Typical precision is about ±10 ms, shown on every result. Optional device latency calibration measures your phone's display and touch delay and subtracts it.
- Leaving before green is a red light, shown with its minus time. A .000 perfect is saved like any other run.

5-light grid start

Five pairs of red lights come on one per second, then all go out after a random hold. React to lights out; a jump start shows how early you were.

Shift light run

Launch on green, then shift through five gears when the LED shift light bar flashes. The tachometer climbs more slowly in each gear. Every shift is scored in milliseconds early or late, and hitting the rev limiter costs points. Three generic engine sounds: light 4-cylinder, street 6-cylinder and V8-type, all synthesized.

Statistics

- Latest 100 runs per mode, record time, average, consistency (standard deviation) and red-light rate.
- Reaction time histogram and run list, filter by tree type, delete history any time.
- Your personal record on the home screen and on every result.

Made for practice

- Dark realistic tree with incandescent bulbs and lens glow, large launch pad, portrait layout.
- Sound, tree beep and vibration each have their own switch. Vibration happens only with the result, never on green.
- Every mode and setting is available with no credits, energy or time limits. No account needed; your history stays on your phone.

For bracket racers, track-day drivers and motorsport fans who want to sharpen their launch. Use it for track practice only, never on public roads.

Recent changes:
New: Signal Duty. Sound real railway signals by hand — grade crossing, station departure, release brakes, backing up — and be judged on the length of every blast and your rhythm. Earn stars, move up the ranks, try the strict tier and the daily signal. Whistle or horn, the scene reacts as the gates come down.