Skip to content
WhatIf
Worlds
Home
Worlds
Simulations
Learn
About
Get Started
Esc
Traffic World
Explore traffic, congestion, and how small changes have big effects.
World
Nature World
Explore ecosystems, populations, and the balance of life.
World
Traffic Ring
What if one busy stop changed when the buses arrive?
Simulation
Phantom Jam
What if one driver brakes hard, for no reason at all?
Simulation
Green Light
What if drivers trusted the car ahead to go?
Simulation
Predators & Prey
What if the grass grew back much faster?
Simulation
←
Simulations
Phantom Jam
What if one driver brakes hard, for no reason at all?
Learn
Average speed
52
km/h
Cars stopped
0
of 40
Slowest car
52
km/h
Tap a car to take control of it
Pause
Reset
1×
2×
4×
8×
20×
50×
Hit the brakes