A near miss is a statistically significant speed and g-force event. It shows where drivers are losing friction with the road.
A near miss is a statistically significant speed and g-force event that falls under one of three categories of causation: braking, steering, or a combination of both. This algorithm is based on substantial road safety literature, and a series of real-world experiments.
A near-miss acts as a leading indicator, identifying where potentially high-risk intersections or roads exist across a transport network.
It typically implies that the vehicles involved were in a potentially dangerous situation where an accident could have occurred, but due to timely actions by the drivers or other factors, a collision was prevented. Despite the absence of a collision, a near miss is considered a serious incident that highlights the importance of safe driving practices and situational awareness on the road.
There is a difference to the typical definition of a near miss and how near miss is described in Compass data. Compass refers to near misses as:
An occurrence involving a rapid evasive maneuvre (from braking or steering or a combination of both)
This means that the near miss values shown in the data outputs indicate that above or below a certain threshold the ‘near miss’ algorithm is triggered as the vehicle is about or has lost friction with the pavement during a braking, accelerating or swerving event.
The ‘near miss’ algorithm uses a range of different acceleration (g force) and speed thresholds depending on the vehicle type i.e. whether it is a HCV, LCV, car, or bus. These thresholds are shown in the next slide
The Role of g-forces
A “G-Force” is a measure of acceleration. 1 G is the acceleration due to the force of gravity. It is measured in m/sec2. The acceleration of braking and swerving is the equivalent force to gravity. G-forces provide a measure of the intensity of a near-miss and the direction or data (i.e., left vs right or acceleration vs deceleration)
In the Compass data, there are 3 types of g-forces showed in the Compass outputs:
- Braking: -x
- Accelerating: + x
- Swerving: – y (left swerving) and + y (right swerving)
The thresholds for different types of vehicles are shown below:
