You might have observed placards in vantage points of our highways like 'Accident-prone zones. Go Slow'. Interestingly that section of the road would be quite clear devoid of complex highways and ambient lighting. The road would also be perfectly bitumen-topped. So from where on earth is this section succumbing to traffic hazards? The most nearest cause of this might be a negative (black) energy that is haunting this place.
When some one dies in an accident the subtle body of the deceased is angered by it and possesses the place. It keeps growing its circle by creating more such accidents in that spot. Building memorials at that spot would only increase the distress of the subtle body thus accelerating the trouble even more.