any condition that makes it difficult to make progress or to achieve an objective; "intolerance is a barrier to understanding"

a barrier set up by police to stop traffic on a street or road in order to catch a fugitive or inspect traffic etc.

an obstacle which you have the power to control

Roadblock is a 1951 black-and-white film noir starring Charles McGraw. The 73-minute crime thriller was shot on location in Los Angeles, California. The cinematography is by Nicholas Musuraca.

Roadblock is a robot built to compete in the BBC television series of Robot Wars. The robot won Series 1 and competed in Series 2. The robot had a wedge made from a road sign with a petroleum powered circular saw attached.

Roadblock is a fictional character from Hasbro's G.I. Joe: A Real American Hero series of toys, comics and cartoon. He is one of the most prominent African-Americans in the series.

a task only one person can complete and no person can complete more than six the entire race

a task only one person can perform

a task only one person may complete

a pick who frustrates a large number of gamesters by remaining alive all year, particularly in the Wild Card spot.

a challenge that

A Web page that serves no other purpose other than to let you know that there is nothing available at this URL, but that something will be coming soon.

Scheduling of commercial time on all available stations at a fixed time.