[Autoware] What the magic number 3.6 mean?

edit

Hello, experts. What the magic number 3.6 on astar_avoid.cpp mean?

avoid_start_velocity_ / 3.6

the avoid_velocity value is a flag to switch the planning logic like this.

bool avoid_velocity = (current_velocity_.twist.linear.x < avoid_start_velocity_ / 3.6);  
....
else if (state_ == AstarAvoid::STATE::STOPPING)
{
  bool replan = ((ros::WallTime::now() - start_plan_time).toSec() > replan_interval_);

  if (!found_obstacle)
  {
    ROS_INFO("STOPPING -> RELAYING, Obstacle disappers");
    state_ = AstarAvoid::STATE::RELAYING;
  }
  else if (replan && avoid_velocity)
  {
    ROS_INFO("STOPPING -> PLANNING, Start A* planning");
    state_ = AstarAvoid::STATE::PLANNING;
  }
}

I couldn't understand why it have to be 3.6. Does it have a reason mathmatically?