Auto Safety Distance Parameter for NPS vehicles

This section describes about the Auto Safety Distance function, related terms and more.

At first, Auto Safety Distance value was automatically applied to prevent collisions between NPC vehicles, but we now aimed to provide a better testing environment for users to customize it.

Additionally, we added a parameter for the distance interval among NPC vehicles.

NPC vehicle Parameter

You can switch on/off the Auto Safety Distance toggle.

• When OFF the Auto Safety Distance,

  • Safety Distance (m)

    • Click Safety Distance (m) and directly input the value.

  • Time To Collision (s)

    • Click Time To Collision (s) and directly input the value.

When disenable the Auto Safety Distance (OFF) and switch to the Safety Distance Custom Mode,
“If Auto Safety Distance Mode is turned off, collisions between NPCs may occur“ notice comes out.

Safety Distance

[NPC Spawn Point - Safety Distance Custom Mode]

Terms

• User Custom Safety Distance

  • If the direction is forward, the range from the front bumper of the Spawned Vehicle to the entered distance in the parameter.

  • If the direction is Backward, the range from the rear bumper of the Spawned Vehicle to the entered distance in the parameter.

• Leading Vehicle Distance

  • Defined as the distance between the front bumper of the spawned Vehicle and the rear bumper of the closest vehicle in front.

  • It can be calculated using the following formula:

    Leading Vehicle Distance=(Distance between Leading Vehicle Position and Spawn Vehicle Position)−((Distance from Leading Vehicle’s rear axle to its rear bumper)+(Distance from Spawn Vehicle’s rear axle to its front bumper))

• Following Vehicle Distance

  • Defined as the distance between the rear bumper of the spawned vehicle and the front pumper of the closest vehicle in front.

  • It can be calculated using the following formula:
    Following Vehicle Distance=(Distance between the Following Vehicle Position and Spawn Vehicle Position)−(Distance from Spawn Vehicle’s rear axle to its rear bumper)+(Distance from Following Vehicle’s rear axle to its front bumper)

• Minimum Safety Distance Range

  • Required minimum safety distance range for a vehicle to spawn

    • In the Forward direction: The distance from the Spawn Point to the front bumper of the spawning vehicle.

    • In the Backward direction: The distance from the Spawn Point to the rear bumper of the spawning vehicle.

Spawn Condition

• There should be no vehicles in the Minimum Safety Distance Range.

• Both the Forward Spawn Condition and the Backward Spawn Condition must be satisfied, with variations based on the specified modes. The modes are as follows:

  • Auto Safety Distance Mode

  • Safety Distance Custom Mode - Safety Distance (m) Mode

  • Safety Distance Custom Mode - TTC (Time To Collision) (s) Mode
    

Auto Safety Distance Mode

• Internally set MORAI SIM safety distance

  • Forward Safety Distance

    • Braking Distance of spawn velocity (Spawned vehicle) + 2.1 seconds Brake Reaction Distance + 1m Buffer Margin

  • Backward Safety Distance

    • Braking Distance of current velocity (Following Vehicle) + 2.1 seconds Brake Reaction Distance + 1m Buffer Margin
      

Safety Distance Custom Mode

Safety Distance (m) Mode

• A mode which the User Custom Safety Distance value that the user entered is applied in spawn condition.

• Spawn if there is no NPC vehicles in Minimum Safety Distance Range, and both the Forward Spawn Condition and the Backward Spawn Condition are satisfied.

  • Forward Spawn Condition

    • User Custom Safety Distance < Leading Vehicle Distance

  • Backward Spawn Condition

    • User Custom Safety Distance < Following Vehicle Distance

• The maximum value of Safety Distance (m)= (Link Velocity where the current spawn point is located) X (Max TTC : 20s)
  

TTC (Time To Collision) (s) Mode

• A mode which the User Custom Safety Distance is applied based on the distance value calculated from the TTC (s) value entered by the user and the vehicle's speed.

• Spawn if there is no NPC vehicles in Minimum Safety Distance Range, and both Forward Spawn Condition and Backward Spawn Condition are satisfied.

  • Forward Spawn Condition

    • Forward User Custom Safety Distance < Leading Vehicle Distance

    • Forward User Custom Safety Distance = [(Spawn Vehicle의 spawn velocity(m/s)) - (Leading Vehicle의 current velocity(m/s))] X TTC(s)

    • If the current velocity of the Leading Vehicle is faster than the spawn velocity of the Spawn Vehicle, the User Custom Safety Distance value is applied as 0.

  • Backward Spawn Condition

    • Backward User Custom Safety Distance < Following Vehicle Distance

    • Backward User Custom Safety Distance = [(Following Vehicle의 current velocity(m/s)) - (Spawn Vehicle의 spawn velocity(m/s))] X TTC(s)

    • If the current velocity of the Following Vehicle is faster than the spawn velocity of the Spawn Vehicle, the User Custom Safety Distance value is applied as 0.

• The maximum value of TTC (s) is 20s.