See if you can figure out some of our favorites. (Get your bike street smarts dialed with tips found in the Bicycling Complete Book of Road Cycling Skills!)
Read the original article on Bicycling.com.
Cyclists: Watch out for airborne horse-drawn carriages.1 of 9
Where it is: Cuba
What it means: "Horse-drawn carriage and bicycle exclusion zone."
Something—quicksand? A giant Lego?—is about to eat your front wheel so prepare to crawl to safety.2 of 9
Where it is: Portland
What it means: Hit the train tracks as close as you can to a 90-degree angle, or your wheel might get stuck—launching you over the handlebars.
Snakes! Snakes are coming after your tires!3 of 9
Where it is: Everywhere
What it means: Ride with caution—road surface could be slippery or otherwise dangerous.
Lock your bike, or Superman might steal it.4 of 9
Where it is: Unknown
What it means: Please don't do this? (But if you need to, make sure you film it like this guy.)
Tuck low in the aero position and prepare to meet your clone in a space-time implosion at this intersection.5 of 9
Where it is: San Francisco
What it means: Drivers, be alert to potential collisions: Cyclists are crossing from both sides ahead. (This one is less confusing when you realize it's aimed at warning drivers and not cyclists.)
There's a disjointed hospital ahead? You're about to enter a Frogger-like crossing situation? Prepare to limbo under this upcoming chain? We had so many theories.6 of 9
Where it is: Boston
What it means: Bikes, cross here ahead.
That idea you just had to sneak up on an unsuspecting pedestrian and ram him or her from behind? It's funny. Go with it.7 of 9
Where it is: Japan
What it means: Dismount your bike and walk.
Bikes everywhere—backpacking, poppin' wheelies, coming from all sides, riding in every direction. Chaos!8 of 9
Where it is: Switzerland
What it means: You're at an intersection of bike paths. Go any direction you want!