Tap the pad to start, then tap on the green lamp and keep still on red.
green circle
red square
amber diamond
This test switches shapes and lamps on and off, never more than three times a second and with no fades. Skip it if flashing lights trouble you.
More options
The game as it is played: two lamps, red on top and green below. Press on green, keep still when red lights. Ten lights, three of them red.
–This run
–Your best
–Last run
10 signals after a random wait of 1.5 to 4 seconds: 7 to go on and 3 to hold on, shuffled every run. Go on the green circle; keep still on the red square. The lamps sit in a column, and one lights at a time. A signal stays for 1.5 seconds. A press on a hold is a false alarm, and a go signal left unanswered is a miss. The result is the average of your hits in milliseconds, with the false alarms and misses beside it. A press before the signal is a false start and the try is repeated.
Amber joins the lightsThree lamps now, as on a road signal: red, amber, green from the top. Amber is a hold too, so only the bottom lamp is a go.
The caller loves redSixteen lights, eleven of them red. After a long run of freezes, the hand wants to move on anything, which is what the game is built to catch.
Fast callerShort gaps of 0.8 to 1.5 seconds and lamps that stay lit only one second, like a caller who turns round quickly.
Green light go, red light freezeThe game as it is played: two lamps, red on top and green below. Press on green, keep still when red lights. Ten lights, three of them red.
Slow caller, sudden greenGaps of 3 to 8 seconds. Attention drifts during a long wait, so this round shows what a slow caller does to your time.
Space bar for your feetOnly a key press counts. Rest a finger on the space bar and keep it still through every red.
Show all 15 rounds and notes (9 more)
Change the rule 2
Freeze on green insteadThe rule turned round: press on red and keep still on green. Habit pulls the other way, so expect a false alarm or two.
Go on amber onlyThe middle lamp is the go. Red above and green below are both holds, so the eye has to find the position as well as the colour.
Warm up and compare 2
All green, nothing to freeze onSeven greens and no red: a plain reaction time on the same lamp. The first round sets its result beside this one, so you see what the decision costs.
Warm-up, five lightsFive lights, two of them red, not saved. Use it to find the pad and the rhythm before a scored round.
The game and the lamps 5
Hit, miss and false alarmA press on the go lamp is a hit and is timed. A press on a hold lamp is a false alarm and is counted, never timed. A go lamp you let pass is a miss.
The order of the lampsThe page stacks its lamps as a vertical traffic signal does: red at the top, amber in the middle, green at the bottom. Each colour also has its own shape, so colour is never the only cue.
What the time includesYour time runs from the frame the lamp lit to the press the browser saw, so it includes the screen and the mouse or keyboard as well as you. Compare runs on the same device.
Where the game comes fromRed Light, Green Light is the North American name of the playground game Statues. The caller turns away and calls green light, then spins round on red light, and anyone seen moving goes back to the start.
Why red comes more oftenWhen most lights are go, pressing becomes automatic and the rare hold is hard to stop for. When most are hold, the rare go comes late. Both show up in your result.
How this list was compiled: Rounds and notes written for this page. The rules of Red Light, Green Light (the North American name of Statues: the caller calls green light and red light, players freeze on red, and a player seen moving goes back to the start): https://en.wikipedia.org/wiki/Statues_(game), read 2026-09-24. Traffic light colours (red to stop, amber to signal a change, green to go), arranged in that order: https://en.wikipedia.org/wiki/Traffic_light, read 2026-09-24. The lamp order red, amber, green from the top is the order this page draws. Scoring words (hit, miss, false alarm) describe what the page counts. Nothing on this page tests fitness to drive or anything about health. Licence: own work
How it works
This red light green light reaction time test turns the playground game into a traffic light: press the moment green lights, freeze when red does. You get your average in ms and a count of false alarms.
Read the full guide
Ten rounds, one rule to break
Start with Green light go, red light freeze. Amber joins the lights adds the middle lamp, and The caller loves red makes green rare. Freeze on green instead turns the rule round, which is where habit pulls hardest.
What the numbers mean
Your time is the average of your presses on green, in ms. A press on red or amber is a false alarm: counted, never timed. All green, nothing to freeze on has no decision, and the first round sets your result beside it.
Rest your hand on the mouse or the space bar, not above it. A still hand is what the red light checks.
Questions and answers
Is this a traffic light reaction test for drivers?
No. It borrows the colours of a traffic light but tests nothing about driving. For braking times turned into metres at 30 or 70 mph, try the driver reaction time test.
Why is my time slower here than on the plain test?
You have to decide before you press: green, or red and amber? That choice adds time. Compare with All green, nothing to freeze on, which has no decision, or with the reaction time test.
Is a stoplight reaction test a health check?
No. It measures how fast you pressed on this device, screen and mouse included, and it diagnoses nothing. If you are worried about your reactions, talk to a doctor.