One of the reasons barriers are used on bridges is to:

Barriers on bridges are primarily used to minimize snagging and spinout, which are critical for ensuring the safety of vehicles traveling on the bridge. Snagging can occur when a vehicle makes contact with the edges of the bridge or with other objects, leading to loss of control. Similarly, spinout refers to a situation where a vehicle rotates uncontrollably, which can happen on slippery surfaces or due to sudden maneuvers. By incorporating barriers, bridges help to prevent these incidents, thereby enhancing the safety of both vehicles and their occupants. Barriers act as a protective measure that keeps vehicles within the designated roadway, reducing the risk of accidents that can result from vehicles leaving the roadway or colliding with objects outside the bridge's defined path.

The other options, such as facilitating vehicle maintenance, providing power supply, or establishing pedestrian pathways, do not directly pertain to the primary function of barriers on bridges. Therefore, the function of minimizing snagging and spinout stands out as the most relevant and critical reason for the installation of barriers.