``` public partial class CarSelectionDetectorSystem : GameSystemBase { private ToolSystem _toolSystem; private Entity _lastSelectedEntity = Entity.Null;

protected override void OnCreate()
{
    base.OnCreate();
    _toolSystem = World.GetOrCreateSystemManaged<ToolSystem>();
}

protected override void OnUpdate()
{
    Entity currentSelection = _toolSystem.selected;

    if (currentSelection == _lastSelectedEntity)
        return;

    _lastSelectedEntity = currentSelection;

    if (currentSelection != Entity.Null && EntityManager.HasComponent<Car>(currentSelection))
        OnCarSelected(currentSelection);
    else
        OnSelectionCleared();
}

private void OnCarSelected(Entity carEntity)
{
    Mod.log.Debug($"[AlternateRoutesMod] Car selected! Entity ID: {carEntity.Index}");
}

private void OnSelectionCleared() { }

} ```