The Idiom of the Day

a zebra crossing 

For example:

Meaning: A zebra crossing is a pedestrian crossing that is marked on the road with painted black and white stripes.

• Visitors to Britain are sometimes confused when they're told there's a zebra crossing up ahead. Some even expect to see a zebra walking across the road.
  
• If someone steps onto a zebra crossing, all cars must stop and wait for them to cross the road.
  

Variety: This idiom is typically used in British English but may be used in other varieties of English too.