IPDE – How a Driver Foresees Where Points of Conflict Can Develop
A driver is software that provides an interface between a computer’s operating system and hardware devices. It allows a device to work with the operating system without the application software knowing how to interact with it.
When a driver foresees where points of conflict can develop in a driving situation they are using the predicting step of the IPDE process. This capability is the most important for safe driving.
Conflict events are defined as situations where a crossing vehicle interrupts the progress of a through vehicle for a specific point in time and space – a conflict point – or over a period of time – a conflict line. Algorithms are needed to identify and process this data to determine surrogate measures of safety for these situations. TTC, PET, DR, MaxS, and DeltaS are some of the desired measurements.
The TTC for a conflict event is defined as the difference between the projected arrival time of the through vehicle at its destination with the right-of-way and the time when it realized that it was on a collision course with the crossing vehicle (projected departure time – PT). A minimum TTC value is recorded at each location during this time period.
The PET for a conflict line event is defined as the average of the PETs calculated at each location for this time period. A minimum PET is recorded at each location. The locations of these points – starting and ending latitude and longitude – should be noted for each conflict line event in order to indicate which areas are risk areas.
Identifying traffic conflicts requires a complex combination of a variety of factors. Some of these factors include the defining pattern of a conflict and performed evasive maneuvers. However, they also depend on the environment and driving style of other road users. Moreover, they can be affected by factors such as the line of sight restrictions caused by a hill or the presence of obstacles.
In addition to identifying vehicle trajectory, traffic conflict prediction methods also need to be able to detect when the risk of collision exceeds safety thresholds. These safety thresholds can be defined by the arrival time to collision (TTC), postencroachment time, gap time, and other parameters.
A simulated traffic conflict identification method was developed using vehicle detections and lane-geometry identification, and safety metrics were defined for each scenario. The derived scenarios were then transferred to an integrated simulation framework that consisted of a submicroscopic simulator and a microscopic traffic simulator. This enabled the evasive maneuvers and lane-change and rear-end predictions of the prediction algorithm to be evaluated in an objective and reliable way.
Once you have identified and predicted a possible conflict, you must decide on what you should do. This is the step of the IPDE process called deciding. Deciding is a mental task, much like identifying and predicting.
Finally, you must execute the plan you have decided upon. To execute is to carry out the plan you have decided on, in full. If you execute all of the difficult steps in a dance perfectly, your instructor will be proud. The word execute has a negative connotation in the sense that it is sometimes used to refer to capital punishment for criminal actions. However, this usage is outdated. More commonly, it is used to mean that you are carrying out a duty or obligation.
All of these steps of the IPDE process combine to form a comprehensive driving strategy that is the key to safe, low-risk driving. The area of space all around your vehicle is called the space cushion.