13.11 Tunnels

Tunnels are modeled as objects in ASAM OpenDRIVE. The road with the tunnel object defines the part of the road that is the tunnel or the underpass. By definition, tunnels are valid for the complete cross section of a road. Tunnels are described by a starting point, a length and a type, for example, if the tunnel represents an underpass and is open to daylight. Additional properties may define the light conditions.

Figure 121. Tunnel

Figure 121 shows a tunnel that is valid for the whole cross section of the road and that defines the part that is the tunnel.

Elements in UML model

<tunnel> element

In ASAM OpenDRIVE, tunnels are represented by the <tunnel> element within the <objects> element.

UML class: t_road_objects_tunnel
XML tag:   <tunnel> (Multiplicity: 0..*)

Tunnels are modeled as objects in ASAM OpenDRIVE. The road with the tunnel object defines the part of the road that is the tunnel or the underpass.

Tunnels are valid for the complete cross section of a road unless a lane validity element with further restrictions is provided as child element

Table 102. Attributes of the <tunnel> element
Name	Type	Use	Unit	Description
`daylight`	t_zeroOne	optional		Degree of daylight intruding the tunnel. Depends on the application.
`id`	string	required		Unique ID within database
`length`	t_grEqZero	required	m	Length of the tunnel (in s-direction)
`lighting`	t_zeroOne	optional		Degree of artificial tunnel lighting. Depends on the application.
`name`	string	optional		Name of the tunnel. May be chosen freely.
`s`	t_grEqZero	required	m	s-coordinate
`type`	e_tunnelType	required		Type of tunnel

<validity> element

In ASAM OpenDRIVE, lane validity is represented by the <validity> element within the <object> element.

UML class: t_road_objects_object_laneValidity
XML tag:   <validity> (Multiplicity: 0..*)

Lane validities restrict signals and objects to specific lanes.

Table 103. Attributes of the <validity> element
Name	Type	Use	Description
`fromLane`	integer	required	Minimum ID of the lanes for which the object is valid
`toLane`	integer	required	Maximum ID of the lanes for which the object is valid

XML example

<objects>
    <tunnel s="50.0"
            length="100.0"
            name="ExampleTunnel"
            id="1"
            type="standard"
            lighting="0.2"
            daylight="0.9"/>
</objects>

Rules

The following rules apply to tunnel elements:

Tunnels may be restricted to certain lanes, using the <laneValidity> element.
The @type of the tunnel shall be specified.
The value of the @fromLane attribute shall be lower than or equal to the value of the @toLane attribute.

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