The IPDE Method of Driving
The "foundation" of the IPDE method of driving, "IDENTIFY," is reliant upon a driver's implementation of scanning techniques that serve to discriminate between information that is useful to driving and "non-driving" visual information. To aid in this process, a driver must practice scanning the driving environment for the primary purpose of IDENTIFYING real and potential hazards, e.g., an oncoming vehicle in your lane of travel or a child playing near the roadway, respectively.
The second step in the IPDE method is to PREDICT what might happen should you encounter a real or potential hazard.
For real hazards, such as an oncoming vehicle that drifts into your lane of travel, simply predict whether the oncoming vehicle will continue toward your car and, if so, what consequences the oncoming car's path of travel might involve. As with any dynamic environment, your prediction process might require a re-assessment if another real hazard is identified between you and the oncoming vehicle — such as a child runs into the street chasing a ball directly in front of your vehicle.
The third step in the IPDE method is to DECIDE what driver action you will implement (accelerate, steer, decelerate, or any combination of these vehicle control maneuvers) to avoid a crash with a real (or potential) hazard. This process requires an understanding of the need for necessary time and space to implement the "decided-upon" vehicle control maneuver. Before you implement an avoidance maneuver, be certain that your chosen escape path is still available and access space is available (leaving the roadway) if you have to implement a "less desirable" emergency avoidance maneuver.
To EXECUTE is to carry out your decided-upon action. This process might range from gently moving toward the left portion of your lane when approaching a vehicle parked on the side of the roadway for repairs (a driver changing a flat tire) to implementing an emergency avoidance maneuver. Generally, your skill in implementing avoidance maneuvers will increase commensurably with driving experience.
The driver of a vehicle approaching an intersection must yield the right of way to a vehicle which has entered the intersection from a different highway. Before entering an intersection, the driver should:
- Identify that governing traffic control devices at the intersection are working appropriately
- Be aware that other drivers may or may not comply with their respective traffic control devices. Remember what you learned about scanning techniques — it only takes one person who disregards the law at an intersection to cause a devastating turn of events
- Determine when the intersection is safe to enter. Make certain that the device controlling the traffic in your lane is indicating that it is safe for you to proceed. As you enter and pass through the intersection, leave enough room in front of you to ensure a safe cushion for maneuverability
- Use your foot to "cover the brake" as you proceed through the intersection. By covering the brake pedal, you significantly reduce the reaction time necessary to respond to a hazard and also allow the vehicle to slow by removing your foot from the accelerator. The "covering the brake" technique can be used effectively in the following situations: (1) When driving next to parked cars, (2) when you see the brake lights of other cars, and (3) when approaching signal lights.
Remain aware and continually scan the intersection. In a worst case scenario, you want to be prepared to take whatever action may be necessary to avoid a crash by ensuring that you have the minimum stopping or maneuvering distance available if necessary.
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This article was written by SafeMotorist.com defensive driving staff writers and reviewed for accuracy by defensive driving instructors. All articles are based on current traffic laws and defensive driving practices. This article is intended for educational purposes only, and should not be taken as legal advice or literal interpretation of any specific traffic law.