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179. Consecutive ego merge

Scenario location: $FTX_PACKAGES/base_scenarios/scenarios/ego_merge/consecutive_ego_merge/

The consecutive_ego_merge scenario simulates two forced merge maneuvers occurring in quick succession. It challenges the Ego’s ability to recover from the first merge and safely adapt to the second within a limited reaction time.

179.0.1 Actors

Actor Description Type Depiction
ego Vehicle under test vehicle
lane_1_lead_vehicle Vehicle driving ahead of the lane_1_traffic_vehicle in the first merging lane vehicle
lane_1_traffic_vehicle Vehicle in the first merging lane vehicle
lane_2_lead_vehicle Vehicle driving ahead of the lane_1_traffic_vehicle in the second merging lane vehicle
lane_2_traffic_vehicle Vehicle in the second merging lane vehicle
Figure 1: Initial phase of consecutive Ego merge

179.1 Prerequisites

Environmental requirements: A highway with a forced merge point, such as lane ending, road split, ramp exit, or on-ramp.

179.2 Scenario essence

179.2.1 phase_essence

179.2.1.1 phase_essence_first_merge

Ego: The Ego drives from the start of first_merge_road, changes to lane 1 to merge with traffic, and completes its drive at a specified offset from the end of traffic_road.

lane_1_lead_vehicle: At the start of the phase, the lane_1_lead_vehicle is positioned in lane 2, ahead of the Ego by a specified time gap, and drives along the traffic_road.

lane_1_traffic_vehicle: The lane_1_traffic_vehicle is positioned in the same lane as the lane_1_lead_vehicle and maintains a specified time gap behind it at both the start and end of the phase.

lane_2_lead_vehicle: The lane_2_lead_vehicle is positioned in the lane left of the lane_1_traffic_vehicle and maintains a consistent traffic_speed along the traffic_road.

lane_2_traffic_vehicle: The lane_2_traffic_vehicle is positioned in the same lane as the lane_2_lead_vehicle and maintains a specified time gap behind it at the end of the phase.

179.2.1.2 phase_essence_highway_traffic

Ego: The Ego drives from the start of first_merge_road, changes to lane 1 to merge with traffic, and completes its drive at a specified offset from the end of traffic_road.

lane_1_lead_vehicle: The lane_1_lead_vehicle continues to drive along the highway at a steady traffic_speed and completes its drive in the lane_2_lead_vehicle's lane.

lane_1_traffic_vehicle: The lane_1_traffic_vehicle continues to drive, maintaining a specified time gap behind the lane_1_lead_vehicle.

lane_2_lead_vehicle: The lane_2_lead_vehicle continues to drive along the highway, maintaining its lane and a steady traffic_speed.

lane_2_traffic_vehicle: The lane_2_traffic_vehicle continues to drive, maintaining a specified time gap behind the lane_2_lead_vehicle.

179.2.1.3 phase_essence_second_merge

Ego: The Ego continues to drive to the end of the second_merge_road.

lane_1_lead_vehicle: At the start of the phase, the lane_1_lead_vehicle maintains a constant speed and a specified combined time gap behind the lane_2_lead_vehicle.

lane_1_traffic_vehicle: The lane_1_traffic_vehicle continues to drive at a constant speed.

lane_2_lead_vehicle: The lane_2_lead_vehicle continues to drive at a constant speed.

lane_2_traffic_vehicle: The lane_2_traffic_vehicle continues to drive at a constant speed.

179.3 Scenario Main phases

The consecutive_ego_merge main scenario is structured into three distinct phases.

179.3.1 phase_ego_warm_up

The phase_ego_warm_up invokes the consecutive_ego_merge_ego_warm_up scenario.

179.3.2 phase_essence

The phase_essence invokes the phase_essence

179.3.3 phase_post

The phase_post invokes the consecutive_ego_merge_post scenario.

179.4 Parameters

Paths to the CSV file and the main CSV file are as follows:

$FTX_PACKAGES/base_scenarios/test_suites/test_suite_definitions/ego_merge/consecutive_ego_merge.csv
$FTX_PACKAGES/base_scenarios/test_suites/test_suite_definitions/ego_merge/consecutive_ego_merge_main.csv
The parameters you can constrain to create tests with the consecutive_ego_merge.csv file are as follows:

Parameter Description Range
gen_traffic_speed Generated speed of traffic vehicles [0..150]kph
gen_time_gap_between_lane_1_vehicles Generated time gap between vehicles in the first merging lane during first_merging_phase [1..5]s
gen_time_gap_between_lane_2_vehicles Generated time gap between vehicles in the second merging lane during first_merging_phase [1..5]s
gen_ego_lon_lane_dist_to_merge_location_at_start Generated longitudinal lane distance between the Ego and the merge location at the start [100..230]m
gen_combined_lane_time_gap Generated time gap between lead vehicles during second_merging_phase [1..5]s
gen_ego_speed_at_start Input speed of the Ego at the start of the scenario [0..150]kph

179.5 Events

Event Description
ego_stopped Ego speed is slower than 1kph for a delay of ego_complete_stand_still_time
ego_merge_to_highway_complete Ego completes the merge onto the highway

179.6 Metrics

Metrics collected during test execution are given below.

179.6.1 Coverage

The coverage metrics are given below.

179.6.1.1 Coverage items

The multi-dimensional situations captured during the test execution are as follows:

Item Description Range Unit/Type
traffic_speed Speed of traffic vehicles [0..150), every: 10.0 kph
gen_traffic_speed Generated speed of traffic vehicles [0..150), every: 10.0 kph
gen_time_gap_between_lane_1_vehicles Generated time gap between vehicles in the first merging lane during first_merging_phase [1..5), every: 0.5 s
gen_time_gap_between_lane_2_vehicles Generated time gap between vehicles in the second merging lane during first_merging_phase [1..5), every: 0.5 s
gen_ego_lon_lane_dist_to_merge_location_at_start Generated longitudinal lane distance between the Ego and the merge location at the start [100..230), every: 20.0 m
gen_combined_lane_time_gap Generated time gap between lead vehicles during second_merging_phase [1..5), every: 0.5 s
time_gap_between_lane_1_vehicles Time gap between vehicles in the first merging lane during first_merging_phase [1..5), every: 0.5 s
ego_lon_lane_dist_to_merge_location_at_start Initial distance between the Ego and the merge location at the start [100..230), every: 20.0 m
time_gap_between_lane_2_vehicles Time gap between vehicles in the second merging lane during first_merging_phase [1..5), every: 0.5 s
ego_position_to_traffic_at_highway_merge Position of the Ego relative to traffic when merging onto the highway no_merge, before_traffic, within_traffic, after_traffic ego_position_to_traffic
combined_lane_time_gap Time gap between lead vehicles during second_merging_phase [1..5), every: 0.5 s
[Click] The coverage items inherited from the sut.ego_merge_family_base scenario are as follows:
Item Description Range Unit/Type
merge_location_type The Ego merge type (ramp/ lane end/ ramp exit/ road split) acceleration_lane, ramp_to_exit, lane_end, road_split force_merge_type
ego_merge_side The Ego merge side to the highway or lane end left, right av_side
merge_side_of_merging_vehicle The merge side of the merging vehicle left, right force_merge_side
[Click] The coverage items inherited from the sut.generic_base scenario are as follows:
Item Description Range Unit/Type
gen_ego_speed_at_start Input speed of the Ego at the start of the scenario [0..150), every: 10.0 kph
ego_speed_at_start Actual speed of the Ego at the start of the scenario [0..150), every: 10.0 kph

179.6.1.2 Cross coverage items

The test execution data for the combination of multiple coverage items is as follows:

Item Description Referred coverage items
-- -- --
[Click] The cross coverage items inherited from the sut.ego_merge_family_base scenario are as follows:
Item Description Referred coverage items
cross_ego_merge_side_merge_location_type The cross coverage of the Ego merge side and merge location type ego_merge_side, merge_location_type
[Click] The cross coverage items inherited from the sut.generic_base scenario are as follows:
Item Description Referred coverage items
-- -- --

179.6.2 KPI

The key performance indicators are given below.

179.6.2.1 Record items

The performance metrics and the data items captured during the test execution are as follows:

Item Description Range Unit/Type
gap_size_for_first_merge_of_ego Gap size for the Ego during the first merge [0..200), every: 25.0 m
gap_size_for_second_merge_of_ego Gap size for the Ego during the second merge [0..200), every: 25.0 m
max_time_gap_actors_first_merge Maximum time gap between actors during first merge (gap touched by ego) s
min_time_gap_actors_first_merge Minimum time gap between actors during first merge (gap touched by ego) s
max_time_gap_actors_second_merge Maximum time gap between actors during second merge (gap touched by ego) s
min_time_gap_actors_second_merge Minimum time gap between actors during second merge (gap touched by ego) s
speed_difference_actor_ego_and_first_lane_change Speed difference between ego and actor behind ego when changing lanes in first merge kph
speed_difference_actor_ego_and_second_lane_change Speed difference between ego and actor behind ego when changing lanes in second merge kph
ego_stopped_bool Did the Ego stop true, false bool
first_ego_merge First merge of the Ego true, false bool
[Click] The KPIs inherited from the sut.ego_merge_family_base scenario are as follows:
Item Description Range Unit/Type
-- -- -- --
[Click] The KPIs inherited from the sut.generic_base scenario are as follows:
Item Description Range Unit/Type
-- -- -- --

179.7 Checks

Default Severity Description Issue kind Threshold
warning A warning is issued if the Ego was not able to merge into the target lane ego_stopped_warning -