The Direction of Life / Triangular Warning Signs

Triangular Warning Signs.
When a moving car runs into an accident and stops moving, we will place a triangle warning sign behind the car, so as to hint running vehicles behind to drive with caution.
But we can not guarantee that our cars are in the outside lane and our cars may stop when we are driving in the inner lane. Then we need to guide cars coming and going to the suitable direction to better protect our lives. At this time, the guided direction could be easily changed by flipping the triangle sign 180 degrees