Flow vehicle problems: collision avoidance behavior

Question

In main_UrbanRoadway.py, I generate 3 types of vehicle flows with the help of vehicle.add() defined in flow.core.params.py

Requirements

My requirements for vehicle flows are shown as follows:

1. Follow the specified acceleration and speed range even under emergency situations which may lead to collisions;

2. Allow for possible collisions to take place.

Problems occurred

1. If I set the speed mode as "aggressive"(e.g. SumoCarFollowingParams(speed_mode='aggressive')), will the generated flow follow the acceleration & speed limit set by me in additional_params?

2. According to the docs, the "obey_safe_speed" mode prevents vehicles from colliding longitudinally, but can fail in cases where vehicles are allowed to lane change. If I set the speed mode as "obey_safe_speed", will the generated flow goes beyond the limit in avoidance with possible longitudinal collisions?

One of my vehicle types is shown below:

vehicles = VehicleParams()

vehicles.add(veh_id="hdv",
             lane_change_params=SumoLaneChangeParams('only_strategic_safe'),
             car_following_params=SumoCarFollowingParams(speed_mode='aggressive', min_gap=5, tau=1, max_speed=MAX_HDV_SPEED),
             acceleration_controller=(IDMController, {})
             )