For what purpose may this road sign be installed?

• 1For the purpose of preventing oncoming travel of vehicles on sections of roads with one-way traffic.
• 2For the purpose of preventing vehicles from moving out against the general flow on a two-lane road with a lane for public transit.
• 3For the purpose of organizing separate entry and exit at areas used for parking vehicles, gas stations, etc.
• 4For the purpose of preventing entry into a separate lane.
• 5Answers 1, 2, 3, and 4.