Barriers

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Feature : Barriers

Description

A barrier is a physical structure which blocks or impedes movement.

Tags

barrier=*

A barrier is a physical structure which blocks or impedes movement. The barrier tag only covers on-the-ground barriers, it does not cover waterway barriers (dams, waterfalls...). See also Routing#Routing obstacles and other conditions requiring special consideration.

Terminology

There are two main types: linear barriers and nodular barriers.

Linear barriers

Symmetric barriers

Examples:

• Wall
• Fence
• Hedge
• Row of bollards

Tagging: draw a way along the barrier location.

Asymmetric barriers

These barriers are not the same height on each side; i.e., the ground level differs on each side. Examples:

• Retaining walls
• City wall

Tagging: draw a way along the barrier location. The direction of the way is important, see natural=cliff for orientation.

If a linear barrier crosses a highway, they must connect with a node at intersection. Always tag this node with the appropriate nodular barrier tag (usually an entrance or a gate), else routing engines don’t know if crossing is possible.

Nodular barriers

Examples:

• Gate.
• Bollard.
• Lift gate (or boom barrier).
• Concrete block.

Tagging: place a node at the location of the barrier on an existing way (either a highway or a linear barrier). Do not place a node-barrier at the junction of two highways, else it will restrict the traffic on both highways.

Note that some barriers (bollards, gates, etc.) may be either linear or nodular barriers.

Routing

Each barrier has its own accessibility defaults. Use tag access=* to override them.

Barriers with undocumented default access imply access=no. This default restriction prevents softwares from routing through undocumented barriers (and generating a potentially unsafe route).

Useful combination

• access=* - to override access restrictions
• height=* - to specify barrier height
• wheelchair=*
• operator=* - to indicate who operates the barrier

See also

• barrier=* - for a detailed list of barriers.
• Proposed features/barriers (approved in 2008)
• Proposed features/New barrier types (approved in 2011)