roadblock

A roadblock is an obstacle that blocks or stops traffic on a road. It's usually something unexpected and can cause a delay.

You've probably driven to work or school and hit a roadblock before. Maybe there was an accident, construction, or even a protest that closed the road. In these situations, drivers have to wait for the situation to be resolved before they can continue on their way. Roadblocks can also happen in other areas like politics or business when something unexpected gets in the way of progress.