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 Human Factors

Advanced training technology is easy to install and operate everyday.


 Teen Facts

LiveDrive, Inc. offers different versions of the trainer for various types of drivers, e.g. novice, impaired, commercial, police.


 Primer Minimize

   1st Concepts:

What is Headway?

Headway is the distance (D) you choose to follow behind a Leading Vehicle (D). When following another vehicle, Headway choice includes (A) the time it takes for the Following Vehicle to traverse the measured distance to the Leading Vehicle, (B) the time it takes for the Leading Vehicle to stop, and (C) the time it takes for the Following Vehicle to stop. Basically, if the sum of A and C is greater than B, then there will be a headway crash.

Much experience is required for a driver to anticipate and then act upon the moment to moment relationship between following Speed and Distance. Most students are taught the Following Time "Rule" for estimating a safe following distance. The Following Time "Rule" is the time it takes for the Leading Vehicle to pass a roadside object and then for that object to reach the Following Vehicle. A 1 or 2 Second Rule is usually suggested for passenger car drivers. Longer times are recommended for commercial drivers. So, in the figure, (A) is the Following Time, or simply just the time it takes for the Training Vehicle to traverse the measured distance. When (A) is less than the set "Rule", the Following Vehicle should increase the distance.

Even if a student is able to both drive and manually count Following Time seconds at various speeds, there is no guarantee that a driver can avoid a headway crash by acting within the 1 or 2 second "Rule". For example, the driver might be distracted or tired, or there may exist roadway hazards and changing traffic conditions. Drivers also differ in their readiness to apply braking force or to maneuver the vehicle to the exent necessary to avoid a crash. So, there are combinations of human, vehicle, and roadway factors that can cause a headway crash that are not easily separable, especially for a novice driver.

EasyDriver® is designed for a driving Instructor (professional, parent, coach, etc) to demonstrate safe headway distances by combining the effects of separate human, vehicle, and roadway factors. This is accomplished while the Student operates the Training Vehicle in actual traffic. For example, the Instructor might select the Following Time method, which continuously computes the Following Time, and then warns the driver when the Following Rule is exceeded. The Instructor can also use the Simulation Method to compute the Danger of Headway Collision Boundary by separately setting or directly measuring the Student's reaction time, the braking forces expected by the Student and Leading Vehicle drivers, and by selecting various traffic and roadway conditions. The technology is particularly adaptable for instructors to preset the Trainer for independent study in their absence.


Why a Trainer?

The National Highway Traffic Safety Administration has shown that rear-end crashes are the most frequent of all crash types. Rear-end crashes are also the most common among young drivers, who are also more likely to strike another vehicle than to be struck. The Trainer is useful because it teaches a Student "where" to observe changes in forward motion, "when" to anticipate danger, and "how" separate factors that can lead to a headway crash. Whereas, drivers might occasionally check their Following Time by counting, the Trainer is an ever vigilant companion that constantly monitors the driver's headway risk. With regular use, the Trainer helps the Student build an accurate mental model of the relationship between speed and distance, which is typically built over a lifetime of learning. It is also an advantage to provide headway training in the context of actual traffic, instead of through instructional CD's or costly driving simulators. The instructional environment and student experience produced by the Headway Trainer motivates Students to take an interest in their learning.

        Public Health Problem:

  • In 2002, Rear-End crashes were the most frequent, comprising about 29.7% of all crashes.
  • Motor vehicle crashes are the leading cause of death for 15 to 20 year olds.
  • Drivers younger than age 18 are the largest group involved in Rear-End striking crashes.
  • In 2002, the cost of crashes involving drivers between 15 and 20 years old was $32.8 billion.
  • In 2002, older people made up 9% of the U.S. population but accounted for 13% of all traffic fatalities.

        Training Problem:

  • Cues for traffic slowing are hidden in the relative motion of vehicles.
  • Leading vehicle motion is less perceptible at the very distance slowing must be detected.
  • Drivers must work to build a mental speed-distance model, achieved only by on-road trial, error, and practice.
  • Headway motion cues are obscured by poor weather, compelling faster speeds and closer headways.
  • Drivers take for granted traffic motion on dry and straight roadways, the condition of most rear-end crashes.
  • Drivers are poor estimators of their own alertness, and of the increasing reaction delay that can lead to a crash.
  • Drivers often underestimate how fast headway conditions change, and of the dangers of distraction.


How does it work?

Headway warnings occur when a Leading Vehicle is detected within a crash detection zone or "Envelop", located immediately in front of the Training Vehicle. The envelop is created mathematically from speed and distance measurements. It's length includes two separate regions, one in front of and one behind a 'danger of headway collision boundary'. The boundary is computed by the selected training method. As the Training Vehicle is driven, the envelop "turns on" in front of the Training Vehicle. The speed of the Training Vehicle determines the envelop length. The faster the speed, the longer the envelop. Headway Training begins when a Leading Vehicle is detected within the envelop.

The "Crash Detection Envelop" operates like a rubber band with one end fixed to the front bumper of the following vehicle. Somewhere in the middle of the rubber band is drawn a mark or line. As the rubber band is stretched outward, you can observe: 1) The "envelop" is flexible and changes length; 2) The position of the mark in the middle of the band changes (representing the danger of collision boundary); and 3) The segments on each side of the center mark (representing the detection zones) change in length but remain proportional. So, when driving, imagine the Envelop stretching outward as speed and other risks increase.

The Figures below show the 2 main detection zones that comprise the Crash Detection Envelop. Different warnings occur depending on where the Leading Vehicle is located inside the Envelop. The "Imminent" zone is located closest to the Training Vehicle, and is the zone where headway warnings become persistent. The forward "Cautionary" zone provides advance detection of Leading Vehicle motion prior to the vehicle crossing the Danger of Headway Collision Boundary. The length of the Envelop depends on the speed of the Training Vehicle. In the first Figure, the Leading Vehicle lies just outside the Envelop.

The second Figure illustrates that the Leading Vehicle has slowed or that the Training Vehicle has accelerated. In each case, the Leading Vehicle is detected inside the Envelop projected in front of the Training Vehicle. The Leading Vehicle is shown located within the "Cautionary" warning zone. If the Training Vehicle reduces speed, the Envelop will shrink proportionally and perhaps locate the Leading Vehicle outside of the Crash Envelop. In the "Cautionary" zone, the student receives periodic messages of encouragement and praise. Inside the "Imminent" crash zone, the student receives danger of headway collision warnings and instructional messages designed to encourage the student to increase their headway distance.

In addition to alarms and messages related to the location of the Leading Vehicle near the Crash Boundary, the Trainer also provides messages about the motion of the Leading Vehicle. There is a second rubberband-like projection, which stretches based only on the actual distance to the Leading Vehicle. In the forward segment, messages inform the student that the Leading Vehicle is Slowing or that the forward Path is blocked (e.g. Leading Vehicle is stopped). In the rearward segment, another message will inform the student of a Cutting-In-Front motion.

Our last figure shows the Leading Vehicle inside the Imminent danger zone. Depending on the type of warning selected, the Student hears either an alarm sound or a verbal warning. Simultaneously, the Trainer detects and announces the movement of the Leading Vehicle as slowing, whether another vehicle just cut-in front, or if the forward path is blocked. If the Leading Vehicle remains in the Imminent crash zone, the Trainer will issue frequent statements to coax the driver to increase the distance. If the driver persists in closing the distance, a separate alarm is provided to indicate tailgating. If the Student pushes beyond the tailgate zone, the Trainer shuts down until a reasonable following distance is detected. EasyDriver® is intended not to distract a Student from responding to an emergency situation.

Basically, while the Student is tracking a forward vehicle the Trainer issues warnings about the danger of a headway crash and alerts the Student about the forward motion of that vehicle. Depending on the response of the Student, the Trainer provides either rewarding praise for keeping a safe distance or negative chiding for following too close. Along with the behavioral conditioning, the Trainer issues safety messages that suggest ways to handle a variety of traffic situations.

EasyDriver® addresses speed management in terms of the skill to keep a safe distance. Speed control is additionally taught by way of the Instructor setting a fixed limit (providing a warning if exceeded), by an automatic Curve-Speed alarm (when driving too fast in a curve), by telling the Student when the general pace of traffic has slowed, and by providing a warning when forward acceleration is too high.


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 Science Links



Rear-end crashes result in the highest economic and human cost than any other crash type. Different editions target special driver groups.


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