Risk assessment should consider how often and how long the worker is alone, the time of day, the forms and reliability of communication including regular contact procedures and cover when away from a vehicle, the location including difficulty of rescue and what happens if a vehicle breaks down, the nature of the work (high risk activities, whether a second person is needed, fatigue, violence and aggression from clients, environmental extremes, animal attack), and the worker's experience, training, judgement and any known medical condition.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.