8.14 Traffic lights :: OpenSCENARIO

8.14.1 Overview

This chapter explains the implementation of traffic lights and how it enables the manipulation of traffic signals in ASAM OpenSCENARIO. The concept allows for the management of traffic lights within the map file, using semantic states and or bulb states.

8.14.2 Traffic light bulbs

ASAM OpenSCENARIO provides enumeration types for icon shape, color, and state to manage and define traffic light bulbs. The structure traffic_light_bulb encapsulates the properties of an individual traffic light bulb.

8.14.2.1 Enum bulb_icon

Available icons for traffic lights. Note that this enum only describes the icons, with the actual colors being irrelevant. For visual representations of the icons, refer to the OpenDRIVE traffic signal code number and table found in OpenDRIVE traffic signal files. Images of the icons can be found at usepastel.com/link/omxxxgy3/#/opendrive-group/opendrive-antora-gen/ASAM_OpenDRIVE_Signal_reference/latest/signal-catalog/01_road_signals/road_signals.html.

Basic information

Table 299. Basic information of enum bulb_icon
Instantiable	yes

Values

Table 300. Enum bulb_icon
Value	Comment
unknown	Unknown icon
circle	OpenDRIVE Type 1000020, 1000001, 1000008, 1000012
pedestrian_walking	OpenDRIVE Type 1000002-20 (a walking pedestrian)
pedestrian_standing	OpenDRIVE Type 1000002-10 (a pedestrian in standing position)
tram	OpenDRIVE Type 1000014 (tram)
bus	OpenDRIVE Type 1000015 (bus)
bicycle	OpenDRIVE Type 1000013-20 (bicycle)
horse_rider	OpenDRIVE Type 1000015 (a person riding a horse)
person_bicycle	OpenDRIVE Type 1000015 (a person riding a bicylce)
bicycle_left	OpenDRIVE Type 1000013-50 (a bicycle as seen driving to the left)
bicycle_right	OpenDRIVE Type 1000013-80 (a bicycle as seen driving to the right)
arrow_left	OpenDRIVE Type 1000020-10 (an arrow pointing left)
arrow_right	OpenDRIVE Type 1000020-20 (an arrow pointing right)
arrow_straight	OpenDRIVE Type 1000020-30 (an arrow pointing straight ahead)
arrow_left_straight	OpenDRIVE Type 1000020-40
arrow_right_straight	OpenDRIVE Type 1000020-50
arrow_diagonal_left	OpenDRIVE Type 1000020-60
arrow_diagonal_right	OpenDRIVE Type 1000020-70
arrow_u_turn_left	OpenDRIVE Type 1000008-80 (an arrow indicating a u-turn to the left)
arrow_u_turn_right	OpenDRIVE Type 1000008-90 (an arrow indicating a u-turn to the left)
arrow_left_right	OpenDRIVE Type 1000012-100
lane_arrow_down	OpenDRIVE Type 1000021
lane_arrow_down_right	OpenDRIVE Type 1000022-10
lane_arrow_down_left	OpenDRIVE Type 1000022-20
lane_cross	OpenDRIVE Type 1000022-23
txt_walk	A textual description meaning "walk"
txt_dont_walk	A textual description meaning "do not walk"
countdown	Numbers for counting down
pt_horizontal_bar	Public transportation OpenDRIVE Type F-0
pt_vertical_bar	Public transportation OpenDRIVE Type F-1
pt_slash_bar	Public transportation OpenDRIVE Type F-2
pt_backslash_bar	Public transportation OpenDRIVE Type F-3
pt_small_circle	Public transportation OpenDRIVE Type F-4
pt_triangle	Public transportation OpenDRIVE Type F-5
switch_x	Public transportation OpenDRIVE Type W-0
switch_v_flipped	Public transportation OpenDRIVE Type W-1
switch_v_left	Public transportation OpenDRIVE Type W-2
switch_v_right	Public transportation OpenDRIVE Type W-3
switch_t	Public transportation OpenDRIVE Type A-1
switch_a	Public transportation OpenDRIVE Type A-X
switch_bar_v	Public transportation OpenDRIVE Type W-14
switch_bar_v_flipped	Public transportation OpenDRIVE Type W-11
switch_bar_v_right	Public transportation OpenDRIVE Type W-12
switch_bar_v_left	Public transportation OpenDRIVE Type W-13
switch_dotted_circle	Public transportation OpenDRIVE Type A-2B

8.14.2.2 Enum bulb_color

The color of a traffic light bulb.

Basic information

Table 301. Basic information of enum bulb_color
Instantiable	yes

Values

Table 302. Enum bulb_color
Value	Comment
unknown	Unknown color
red	Red color
yellow	Yellow color
green	Green color
blue	Blue color
white	White color

8.14.2.3 Enum bulb_state

The state of a traffic light bulb.

Basic information

Table 303. Basic information of enum bulb_state
Instantiable	yes

Values

Table 304. Enum bulb_state
Value	Comment
unknown	Unknown state
is_off	Bulb is off
is_on	Bulb is on
is_flashing	Bulb is flashing

8.14.2.4 Struct traffic_light_bulb

A traffic light bulb.

Basic information

Table 305. Basic information of struct traffic_light_bulb
Instantiable	yes

Parameters

Table 306. Struct traffic_light_bulb
Parameter	Type	Mandatory	Description
map_id	string	no	Unique identifier of the traffic light bulb in the context of the map actor
icon	bulb_icon	yes	The type of traffic light bulb icon
color	bulb_color	yes	The color of the traffic light bulb
icon_positive	bool	yes	True if icon is illuminated (and background is dark), false if icon is dark (and background is illuminated).

State variables

Table 307. State variables of struct traffic_light_bulb
Variable	Type	Mandatory	Description
state	bulb_state	yes	State of the traffic light bulb

Figure 26. Example of icon_positive==false (left) and icon_positive==true (right)

8.14.3 Semantic states

The semantic state of a signal belongs to the rules governing traffic behavior in relation to the signal at a specific point in time. For instance, a signal might be in a semantic stop state, indicating that compliant traffic must not cross a designated stop line associated with the signal. Alternatively, it could be in a semantic caution state, allowing compliant traffic to proceed past the signal but requiring it to yield to other traffic and pedestrians.

8.14.3.1 Enum semantic_traffic_light_state

Rules imposed on traffic obeying the signal at a given point in time.

Basic information

Table 308. Basic information of enum semantic_traffic_light_state
Instantiable	yes

Values

Table 309. Enum semantic_traffic_light_state
Value	Comment
off	Traffic light is turned off
stop	Stop motion
attention	Traffic signal is going to change to go
caution	Obeying traffic may pass the signal but must yield to other traffic
stop_attention	Traffic signal is going to switch to stop
go	Obeying traffic is allowed to drive
go_exclusive	Obeying traffic has exclusive rights to pass. Other crossing traffic members have semantic state stop.
non_functional	Non-functional traffic light. Can be used when a traffic light is in an unrecognizable state (for example, when red and green lights are on together).

The mapping between semantic and physical (bulb) states can vary, especially across regional standards. The traffic_light struct uses the semantic_state_to_state and state_to_semantic_state methods to enable conversion between these representations. The specific conversion mapping can be defined in a separate file, such as 'xxx_regional_settings.osc'.

8.14.4 Traffic light

The traffic_light struct represents a singular traffic light box, such as one with red, yellow, and green bulbs. The order of the bulbs reflects the arrangement of the traffic light. For vertically oriented traffic light boxes the order is from top to bottom. For horizontally oriented traffic light boxes the order is from left to right.

8.14.4.1 Struct traffic_light

A single traffic light box.

Basic information

Table 310. Basic information of struct traffic_light
Instantiable	yes

Parameters

Table 311. Struct traffic_light
Parameter	Type	Mandatory	Description
map_id	string	no	Unique identifier of the traffic light box in the context of the map actor
bulbs	list of traffic_light_bulb	yes	List of traffic light bulbs that are contained in the traffic light box
pose	pose_3d	yes	The physical position and orientation of the traffic light box
height	length	yes	Height of the traffic light box
width	length	yes	Width of the traffic light box
group	traffic_light_group	yes	The traffic light group the traffic light box belongs to

8.14.4.1.1 Methods

Method state_equal()

Checks whether the current bulb states of the traffic light bulbs of this traffic light are equal to the bulb states of the traffic light bulbs in bulbs.

Prototype

extend traffic_light:
    def state_equal(bulbs: list of traffic_light_bulb)-> bool

Return value

True if the current traffic light bulb states of the traffic light are equal to the bulb states of the bulbs in bulbs, otherwise false.

Parameters

Table 312. Parameter for method state_equal()
Parameter	Type	Description
bulbs	list of traffic_light_bulb	List of traffic light bulbs to be compared to the bulbs of the current traffic light in regard to their state.

Method semantic_state_to_state()

Converts the semantic state to a list of traffic light bulbs with the correct bulb icons, colors and states.

Prototype

extend traffic_light:
    def semantic_state_to_state(state: semantic_traffic_light_state)-> list of traffic_light_bulb

Return value

A list of elements of type traffic_light_bulb, ordered according to the position of the bulbs in the traffic light.

Parameters

Table 313. Parameter for method semantic_state_to_state()
Parameter	Type	Description
state	semantic_traffic_light_state	state of the traffic light in semantic representation

Method state_to_semantic_state()

Converts a list of traffic light bulbs to a semantic state of a traffic light by evaluating their icons, colors, and states.

Prototype

extend traffic_light:
    def state_to_semantic_state(bulbs: list of traffic_light_bulb)-> semantic_traffic_light_state

Return value

The semantic state of the traffic light.

Parameters

Table 314. Parameter for method state_state_to_semantic_stateequal()
Parameter	Type	Description
bulbs	list of traffic_light_bulb	A list of traffic light bulbs, ordered according to the position of the bulbs in the traffic light.

The struct traffic_light_group describes a set of traffic light boxes that control the same element of the road. This can either be a single traffic light, or multiple traffic lights that duplicate each other. An example are multiple traffic light boxes facing the same segment of the road, but hanging at different positions. All traffic lights in the traffic light group must have exactly the same state at any given moment of time, unless there is a malfunction or one of the bulbs is burned.

8.14.4.2 Struct traffic_light_group

A set of traffic light boxes that control the same incoming lanes.

Basic information

Table 315. Basic information of struct traffic_light_group
Instantiable	yes

Parameters

Table 316. Struct traffic_light_group
Parameter	Type	Mandatory	Description
map_id	string	no	Unique identifier of the traffic light group in the context of the map actor
bulbs	list of traffic_light_bulb	yes	Union of all traffic light bulbs that are contained in all traffic light boxes of the group
traffic_lights	list of traffic_light	yes	List of traffic lights in the traffic light group
cycle	traffic_light_cycle	yes	Activation_cycle may be null if not specified by the provided control plan (see map.set_traffic_lights_control_file)

8.14.4.2.1 Methods

Method state_equal()

Checks whether the current bulb states of the traffic light bulbs of this traffic light group are equal to the bulb states of the traffic light bulbs in bulbs.

Prototype

extend traffic_light:
    def state_equal(bulbs: list of traffic_light_bulb)-> bool

Return value

True if the current traffic light bulb states of the traffic light group are equal to the bulb states of the bulbs in bulbs, otherwise false.

Parameters

Table 317. Parameter for method state_equal()
Parameter	Type	Description
bulbs	list of traffic_light_bulb	List of traffic light bulbs to be compared to the bulbs of the current traffic light group in regard to their state.

8.14.5 Stop-line

A stop line, whether imaginary or real, indicates the position at which traffic is required to halt when the traffic light is in the semantic stop state. The marking of the stop line is defined by the following enumeration type.

8.14.5.1 Enum stop_line_marking

Type of imaginary or real line that describes the position where the traffic shall stop if the traffic light is in the semantic state stop.

Basic information

Table 318. Basic information of enum stop_line_marking
Instantiable	yes

Values

Table 319. Enum stop_line_marking
Value	Comment
none	No line drawn on the ground.
solid	Stop line is a solid line.
broken	Stop line is a broken (dashed) line.

The following structure represents the stop_line of a traffic_light_group.

8.14.5.2 Struct traffic_light_stop_line

The stop_line of a traffic_light_group.

Basic information

Table 320. Basic information of struct traffic_light_stop_line
Instantiable	yes
Parents	route_element

Parameters

Table 321. Struct traffic_light_stop_line
Parameter	Type	Mandatory	Description
traffic_light_group	traffic_light_group	yes	Group of traffic lights that is related to the stop line
route	route	yes	Route on which the stop line is located
rightmost_lane	uint	yes	The lane index for the rightmost relevant lane controlled by `traffic_light_group`
leftmost_lane	uint	yes	The lane index for the leftmost relevant lane controlled by the `traffic_light_group`
offset	length	yes	The position of the stop line in s-coordinates along the route
secondary_stop_offset	length	yes	The position of the secondary stop line in s-coordinates along the route. By default, only one stop line per traffic_light_group exists, and `secondary_stop_offset` == `offset`
primary_stop_line_marking	stop_line_marking	yes	Type of stop line marking
secondary_stop_line_marking	stop_line_marking	yes	Type of stop line marking for secondary stop line. By default, only one stop line per traffic_light_group exists, and `secondary_stop_line_marking` == `primary_stop_line_marking`

Inherited parameters and variables

Table 322. Inherited parameters and variables of struct traffic_light_stop_line
Parent	Inherited parameters and variables
route	length, directionality, min_lanes, max_lanes, anchors

8.14.6 Traffic light phase

A phase of a traffic light is its state for a certain duration.

8.14.6.1 Struct traffic_light_phase

Definition of the states of a list of traffic light bulbs of a specific traffic light group for a defined time span.

Basic information

Table 323. Basic information of struct traffic_light_phase
Instantiable	yes

Parameters

Table 324. Struct traffic_light_phase
Parameter	Type	Mandatory	Description
group	traffic_light_group	yes	Traffic light group that is addressed by the phase
bulbs_state	list of traffic_light_bulb	yes	List of traffic light bulbs that should be set for the specific group
duration	time	yes	Duration of the phase in seconds

A list of traffic_light_phase elements arranged in chronological order form the struct traffic_light_cycle.

8.14.6.2 Struct traffic_light_cycle

Different possible phases of type traffic_light_phase arranged in chronological order.

Basic information

Table 325. Basic information of struct traffic_light_cycle
Instantiable	yes

Parameters

Table 326. Struct traffic_light_cycle
Parameter	Type	Mandatory	Description
phases	list of traffic_light_phase	yes	The different phases of the cycle in chronological order
synchronization_group_id	uint	yes	Identifier used to synchronize different traffic light groups. All traffic light groups with the same `synchronization_group_id` shall be synchronized, for example in a crossing: If traffic in one direction has a green light, the traffic in the perpendicular direction must have a red light
start_offset	time	yes	Temporal offset of the start of the cycle

8.14.7 Interaction with the map

The traffic lights are located in the map. The map itself is described by the map file.

extend map:
    traffic_light_groups: list of traffic_light_group
    traffic_light_control: list of traffic_light_cycle

Here, the traffic_light_groups is a list of all traffic_light_group defined in the map file. In case the map file or any other source contains information about the corresponding entities of traffic_light_cycle, these shall be kept in the traffic_light_control list. Note that traffic_light_control does not necessarily contain control plans for all traffic_light_groups and can also be empty.

The set_traffic_lights_control_file modifier is used to specify traffic light control cycles with an external file. See map modifier set_traffic_lights_control_file for details.

8.14.8 Actor for controlling traffic_lights

Traffic lights are controlled by an actor traffic_light_controller, which inherits from osc_actor.

8.14.8.1 Actor traffic_light_controller

Actor for controlling traffic lights and traffic light groups

Basic information

Table 327. Basic information of actor traffic_light_controller
Instantiable	yes
Parents	osc_actor

8.14.9 Actions for controlling traffic lights

8.14.9.1 Setting traffic light bulb states

The set_bulb_state action sets the state of a bulb of a single traffic light.

8.14.9.1.1 Action set_bulb_state

Set the state of a single traffic light bulb.

Basic information

Table 328. Basic information of action set_bulb_state
Action ending	The action is instantaneous.

Parameters

Table 329. Action set_bulb_state
Parameter	Type	Mandatory	Description
traffic_light	traffic_light	no	The traffic light to which the bulb belongs. Some bulbs can be independent of traffic lights
bulb_color	bulb_color	yes	Color of the bulb
bulb_kind	bulb_icon	yes	Icon type of the bulb
bulb_state	bulb_state	yes	Bulb state to be set
sync	bool	yes	If true, bulb states of all traffic lights in the same synchronization group are set to a bulb state that is consistent according to map.traffic_light_control

This action is instantaneous, meaning that the state change is immediate and permanent unless another set action is executed. Here sync==true implies that all bulbs in the synchronization group will be set to a state that is consistent according to map.traffic_light_control cycles.

8.14.9.2. Setting traffic light states with a list of `bulb_states`

The set_state action sets the state of a single traffic light.

8.14.9.2.1 Action set_state

Set the state of a single traffic light.

Basic information

Table 330. Basic information of action set_state
Action ending	The action is instantaneous.

Parameters

Table 331. Action set_state
Parameter	Type	Mandatory	Description
traffic_light	traffic_light	yes	The traffic light affected by the action
state	list of bulb_state	yes	List of bulb states to be set by the action
sync	bool	yes	If true, states of all traffic lights in the same synchronization group are set to a state that is consistent according to map.traffic_light_control

This action is instantaneous, meaning that the state change is immediate and permanent unless another set action is executed. Here sync==true implies that all bulbs in the synchronization group will be set to a state that is consistent according to map.traffic_light_control cycles.

8.14.9.3. Setting `semantic_state` of a traffic_light

The set_semantic_state action sets the semantic state of a single traffic light.

8.14.9.3.1 Action set_semantic_state

Set the semantic-state of a single traffic light. If the state is not applicable to the given traffic light, then its state is left unchanged.

Basic information

Table 332. Basic information of action set_semantic_state
Action ending	The action is instantaneous.

Parameters

Table 333. Action set_semantic_state
Parameter	Type	Mandatory	Description
traffic_light	traffic_light	yes	The traffic light affected by the action
state	semantic_traffic_light_state	yes	Semantic state to be set by the action
sync	bool	yes	If true, states of all traffic lights in the same synchronization group are set to a state that is consistent according to map.traffic_light_control

This action is instantaneous, meaning that the state change is immediate and permanent unless another set action is executed. Here sync==true implies that all bulbs in the synchronization group will be set to a state that is consistent according to map.traffic_light_control cycles. If the state is not applicable to the traffic_light then its state will remain unchanged.

8.14.9.4. Setting state of a single bulb in a `traffic_light_group`

The set_group_bulb_state action sets the state of a bulb for all traffic lights of a traffic light group.

8.14.9.4.1 Action set_group_bulb_state

Set state of a single bulb for all traffic lights of a traffic light group.

Basic information

Table 334. Basic information of action set_group_bulb_state
Action ending	The action is instantaneous.

Parameters

Table 335. Action set_group_bulb_state
Parameter	Type	Mandatory	Description
traffic_light	traffic_light	yes	The traffic light group affected by the action
bulb_color	bulb_color	yes	Color of the bulb
bulb_kind	bulb_icon	yes	Icon type of the bulb
bulb_state	bulb_state	yes	Bulb state to be set
sync	bool	yes	If true, states of all traffic lights in the same synchronization group are set to a state that is consistent according to map.traffic_light_control

This action is instantaneous, meaning that the state change is immediate and permanent unless another set action is executed. Here sync==true implies that all bulbs in the synchronization group will be set to a state that is consistent according to map.traffic_light_control cycles. If the state is not applicable to the traffic_light_group then its state will remain unchanged.

8.14.9.5. Setting state of a `traffic_light_group` with a list of `bulb_states`

The set_group_state action sets the state of all traffic lights of a traffic light group.

8.14.9.5.1 Action set_group_state

Set the state for all traffic lights in a traffic light group. If the state is not applicable to the given traffic light, then its state is left unchanged.

Basic information

Table 336. Basic information of action set_group_state
Action ending	The action is instantaneous.

Parameters

Table 337. Action set_group_state
Parameter	Type	Mandatory	Description
group	traffic_light_group	yes	The traffic light group affected by the action
state	list of bulb_state	yes	List of bulb states to be set by the action
sync	bool	yes	If true, states of all traffic lights in the same synchronization group are set to a state that is consistent according to map.traffic_light_control

This action is instantaneous, meaning that the state change is immediate and permanent unless another set action is executed. Here sync==true implies that all bulbs in the synchronization group will be set to a state that is consistent according to map.traffic_light_control cycles. If the state is not applicable to the traffic_light_group then its state will remain unchanged.

8.14.9.6. Setting semantic state of a `traffic_light_group`

The set_group_semantic_state action sets the semantic state of all traffic lights of a traffic light group.

8.14.9.6.1 Action set_group_semantic_state

Set the semantic state for all traffic lights of a traffic light group.

Basic information

Table 338. Basic information of action set_group_semantic_state
Action ending	The action is instantaneous.

Parameters

Table 339. Action set_group_semantic_state
Parameter	Type	Mandatory	Description
traffic_light_group	traffic_light_group	yes	The traffic light group affected by the action
state	semantic_traffic_light_state	yes	List of semantic states to be set by the action
sync	bool	yes	If true, states of all traffic lights in the same synchronization group are set to a state that is consistent according to map.traffic_light_control

This action is instantaneous, meaning that the state change is immediate and permanent unless another set action is executed. Here sync==true implies that all bulbs in the synchronization group will be set to a state that is consistent according to map.traffic_light_control cycles. If the state is not applicable to the traffic_light then its state will remain unchanged.

8.14.9.7 Setting activation cycles

The following action can be used to start the execution of traffic light cycles of any number of traffic_light_group.

8.14.9.7.1 Action play_cycles

This action receives a list of traffic light cycles to control the temporal sequence of the traffic light states of any number of traffic light groups. For each traffic light group the shall be only one cycle.

Basic information

Table 340. Basic information of action play_cycles
Action ending	The action ends when another action that affects the state of any traffic light that is controlled by the current cycles is invoked.

Parameters

Table 341. Action play_cycles
Parameter	Type	Mandatory	Description
cycles	list of traffic_light_cycle	yes	list of traffic light cycles to be executed

The states of the traffic_lights in the groups will be changed according to the specified cycles.

8.14.10 Examples

8.14.10.1 Example 1

The following example shows how to control a traffic light by setting its bulb_states.

Code 74. Control a traffic light by its bulb states

scenario sut.traffic_light_bulb_state_control:
    # traffic light with 4 bulbs, 2 red, 1 yellow and 1 green.
    # This can be either 1 OpenDrive dynamic signal with with 4 bulbs in one line or 3 vertical and one on a side.
    # This can also be 4 separated OpenDrive traffic light signals with one bulb each.

    # define my_traffic_light, constrain it to be any traffic light on the map that has 4 bulbs,
    # with the first two being red, the third yellow and the fourth green
    my_traffic_light: traffic_light with:
        keep(it.bulbs.size() == 4)
        keep(it.bulbs[0].color == red)
        keep(it.bulbs[1].color == red)
        keep(it.bulbs[2].color == yellow)
        keep(it.bulbs[3].color == green)

    # define stop_line, constrain it to be the stop line of the traffic light group that my_traffic_light belongs to
    stop_line: traffic_light_stop_line with:
        keep(it.traffic_light_group == my_traffic_light.group)

    # define a traffic light controller
    my_traffic_light_controller: traffic_light_controller

    # define two times, yellow_time and red_time
    red_time: time with:
        keep(it in [5s..20s])

    yellow_time: time with:
        keep(it in [1s..3s])

    do parallel():
        # let sut travel the whole length of the road that stop_line is located on
        sut_drive: sut.car.drive() with:
            along(stop_line.road, start_offset: 0m, at: start)
            along(stop_line.road, end_offset: 0m, at: end)

        traffic_light_change: serial():
            # Start traffic light with the red bulb turned on
            set_red: my_traffic_light_controller.set_state(my_traffic_light, [is_on ,is_on, is_off, is_off])

            wait elapsed(red_time)

            # Turn off red bulb and turn on yellow bulb, then wait for 2s
            set_yellow: my_traffic_light_controller.set_state(my_traffic_light, [is_off, is_off, is_on, is_off])

            wait elapsed(yellow_time)

            # Turn off yellow bulb and turn on green bulb
            my_traffic_light_controller.set_state(my_traffic_light, [is_off, is_off, is_off, is_on])

8.14.10.2 Example 2

The following example shows how to control a traffic light by setting its semantic state.

Code 75. Control a traffic light by its semantic state

scenario sut.traffic_light_semantic_state_control:
    # define my_traffic_light, constrain it to be any traffic light on the map that has at least 3 bulbs
    my_traffic_light: traffic_light with:
        keep(it.bulbs.size() >= 3)

    # define stop_line, constrain it to be the stop line of the traffic light group that my_traffic_light belongs to
    stop_line: traffic_light_stop_line with:
        keep(it.traffic_light_group == my_traffic_light.group)

    # define a traffic light controller
    my_traffic_light_controller: traffic_light_controller

    # define a time stop_time
    stop_time: time with:
        keep(it in [5s..20s])

    do parallel():
        # let sut travel the whole length of the road that stop_line is located on
        sut_drive: sut.car.drive() with:
            along(stop_line.road, start_offset: 0m, at: start)
            along(stop_line.road, end_offset: 0m, at: end)

        traffic_light_change: serial():
            # Start traffic light in semantic state stop
            set_stop: my_traffic_light_controller.set_semantic_state(my_traffic_light, stop)

            wait elapsed(stop_time)

            # Change traffic_light to semantic state go_exclusive
            set_go_exclusive: my_traffic_light_controller.set_semantic_state(my_traffic_light, go_exclusive)

8.14.10.3 Example 3

This example demonstrates event-based triggering of traffic light states.

Code 76. Trigger traffic light states based on events

scenario sut.go_to_stop_by_event:
    # define my_traffic_light to be any traffic light on the map
    my_traffic_light: traffic_light

    # define stop_line, constrain it to be the stop line of the traffic light group that my_traffic_light belongs to
    stop_line: traffic_light_stop_line with:
        keep(it.traffic_light_group == my_traffic_light.group)

    # define a traffic light controller
    my_traffic_light_controller: traffic_light_controller

    # trigger event 'sut_at_my_traffic_light' when sut distance to stop_line is 10 m and semantic state of my_traffic_light is still go
    event sut_at_my_traffic_light is (sut.car.distance_along_route(stop_line.road, from: from_start) > (stop_line.offset - 10m)) and my_traffic_light.state_equal(my_traffic_light.semantic_state_to_state(go))

    do parallel():
        # let sut travel the whole length of the road that stop_line is located on
        sut_drive: sut.car.drive() with:
            along(stop_line.road, start_offset: 0m, at: start)
            along(stop_line.road, end_offset: 0m, at: end)

        traffic_light_change: serial():
            # Start traffic light in semantic state go
            set_go: my_traffic_light_controller.set_semantic_state(my_traffic_light, go)

            wait @sut_at_my_traffic_light

            # Change traffic_light to semantic state go_exclusive
            set_stop: my_traffic_light_controller.set_semantic_state(my_traffic_light, stop)

8.14.10.4 Example 4

This example shows how to let the traffic light controller play the traffic light control plan defined by the map.

Code 77. Execute the traffic light control plan of a map

scenario sut.drive_with_traffic_lights:

    # define my_traffic_light to be any traffic light on the map
    my_traffic_light: traffic_light

    # define stop_line, constrain it to be the stop line of the traffic light group that my_traffic_light belongs to
    stop_line: traffic_light_stop_line with:
        keep(it.traffic_light_group == my_traffic_light.group)

    # define a traffic light controller
    my_traffic_light_controller: traffic_light_controller

    do parallel():
        # play traffic light control plan for all traffic lights
        play_traffic_light_cycles: my_traffic_light_controller.play_cycles(map.traffic_light_control)
        # let sut travel the whole length of the road that stop_line is located on
        sut_drive: sut.car.drive() with:
            along(stop_line.road, start_offset: 0m, at: start)
            along(stop_line.road, end_offset: 0m, at: end)

8.14.10.5 Example 5

This example illustrates how to create a traffic light control plan for a map.

Code 78. Set up a traffic light control plan for a map

extend top.main:
    # cycles for traffic_light_group 42
    group42_cycle_phase1: traffic_light_phase with:
        # red for 30 seconds
        keep(it.group.map_id == "42")
        keep(it.bulbs_state == [is_on, is_off, is_off])
        keep(it.duration == 19s)
    group42_cycle_phase2: traffic_light_phase with:
        # yellow for 2 seconds
        keep(it.group.map_id == "42")
        keep(it.bulbs_state == [is_off, is_on, is_off])
        keep(it.duration == 2s)
    group42_cycle_phase3: traffic_light_phase with:
        # green for 30 seconds
        keep(it.group.map_id == "42")
        keep(it.bulbs_state == [is_off, is_off, is_on])
        keep(it.duration == 30s)

    group42_cycle: traffic_light_cycle with:
        keep(it.phases == [group42_cycle_phase1, group42_cycle_phase2, group42_cycle_phase3])

    # cycles for traffic_light_group 43
    group43_cycle_phase1: traffic_light_phase with:
        # green for 30 seconds
        keep(it.group.map_id == "43")
        keep(it.bulbs_state == [is_off, is_off, is_on])
        keep(it.duration == 19s)
    group43_cycle_phase2: traffic_light_phase with:
        # yellow for 2 seconds
        keep(it.group.map_id == "43")
        keep(it.bulbs_state == [is_off, is_on, is_off])
        keep(it.duration == 2s)
    group43_cycle_phase3: traffic_light_phase with:
        # red for 30 seconds
        keep(it.group.map_id == "43")
        keep(it.bulbs_state == [is_on, is_off, is_off])
        keep(it.duration == 30s)

    group43_cycle: traffic_light_cycle with:
        keep(it.phases == [group43_cycle_phase1, group43_cycle_phase2, group43_cycle_phase3])

    keep(map.traffic_light_control == [group42_cycle, group43_cycle])

8.14 Traffic lights

8.14.1 Overview

8.14.2 Traffic light bulbs

8.14.2.1 Enum bulb_icon

8.14.2.2 Enum bulb_color

8.14.2.3 Enum bulb_state

8.14.2.4 Struct traffic_light_bulb

8.14.3 Semantic states

8.14.3.1 Enum semantic_traffic_light_state

8.14.4 Traffic light

8.14.4.1 Struct traffic_light

8.14.4.1.1 Methods

Method state_equal()

Method semantic_state_to_state()

Method state_to_semantic_state()

8.14.4.2 Struct traffic_light_group

8.14.4.2.1 Methods

Method state_equal()

8.14.5 Stop-line

8.14.5.1 Enum stop_line_marking

8.14.5.2 Struct traffic_light_stop_line

8.14.6 Traffic light phase

8.14.6.1 Struct traffic_light_phase

8.14.6.2 Struct traffic_light_cycle

8.14.7 Interaction with the map

8.14.8 Actor for controlling traffic_lights

8.14.8.1 Actor traffic_light_controller

8.14.9 Actions for controlling traffic lights

8.14.9.1 Setting traffic light bulb states

8.14.9.1.1 Action set_bulb_state

8.14.9.2. Setting traffic light states with a list of bulb_states

8.14.9.2.1 Action set_state

8.14.9.3. Setting semantic_state of a traffic_light

8.14.9.3.1 Action set_semantic_state

8.14.9.4. Setting state of a single bulb in a traffic_light_group

8.14.9.4.1 Action set_group_bulb_state

8.14.9.5. Setting state of a traffic_light_group with a list of bulb_states

8.14.9.5.1 Action set_group_state

8.14.9.6. Setting semantic state of a traffic_light_group

8.14.9.6.1 Action set_group_semantic_state

8.14.9.7 Setting activation cycles

8.14.9.7.1 Action play_cycles

8.14.10 Examples

8.14.10.1 Example 1

8.14.10.2 Example 2

8.14.10.3 Example 3

8.14.10.4 Example 4

8.14.10.5 Example 5

8.14.9.2. Setting traffic light states with a list of `bulb_states`

8.14.9.3. Setting `semantic_state` of a traffic_light

8.14.9.4. Setting state of a single bulb in a `traffic_light_group`

8.14.9.5. Setting state of a `traffic_light_group` with a list of `bulb_states`

8.14.9.6. Setting semantic state of a `traffic_light_group`