When it comes to journey management teaching staff how to avoid accidents you need to re-learn the alphabet and think acronyms. Because when it comes to reacting experts in the field say they only have between 1.5 and 2.3 seconds to react! So what do ATV drivers and motor cycle drives do to assist them in accident avoidance and PREVENTION and how can you apply this to your fleet drivers!
Having the right workplace culture is essential when it comes to ensuring rules are followed. Those firms that create an ‘awareness culture’, where employees feel comfortable reporting incidents rather than having to hide their mistakes, tend to be able to better manage behavioral risk. “Drawing attention to incidents helps to raise awareness and enables employees to change their behaviour, so that the probability of an incident recurring is reduced. Spotting potential problems at this stage is important: an incident is an accident waiting to happen,”
When you teach accident avoidance in your journey management talks add in, Stopping Sight distance is one of several types of sight distance used in road design. It is a near worst-case distance a vehicle driver needs to be able to see in order have room to stop before colliding with something in the roadway, such as a pedestrian in a crosswalk, a stopped vehicle, or road debris
Add in The average reaction time for humans is 0.25 seconds to a visual stimulus,0.17 for an audio stimulus, and 0.15 seconds for a touch stimulus.
Plus a few variables: Many factors have been shown to affect reaction times, including age, gender, physical fitness, fatigue, distraction, alcohol, personality type, and whether the stimulus is auditory or visual.
Reaction Time Components
When a person responds to something s/he hears, sees or feels, the total reaction time can be decomposed into a sequence of components.
Mental Processing Time
This is the time it takes for the responder to perceive that a signal has occurred and to decide upon a response. For example, it is the time required for a driver to detect that a pedestrian is walking across the roadway directly ahead and to decide that the brakes should be applied. Mental processing time is itself a composite of four substages:
- Sensation: the time it takes to detect the sensory input from an object. (“There is a shape in the road.”) All things being equal, reaction time decreases with greater signal intensity (brightness, contrast, size, loudness, etc.), foveal viewing, and better visibility conditions. Best reaction times are also faster for auditory signals than for visual ones. This stage likely does not result in conscious awareness.
- Perception/recognition: the time needed to recognize the meaning of the sensation. (“The shape is a person.”) This requires the application of information from memory to interpret the sensory input. In some cases, “automatic response,” this stage is very fast. In others, “controlled response,” it may take considerable time. In general, novel input slows response, as does low signal probability, uncertainty (signal location, time or form), and surprise.
- Situational awareness: the time needed to recognize and interpret the scene, extract its meaning and possibly extrapolate into the future. For example, once a driver recognizes a pedestrian in the road, and combines that percept with knowledge of his own speed and distance, then he realizes what is happening and what will happen next – the car is heading toward the pedestrian and will possibly result in a collision unless action is taken. As with perception/recognition, novelty slows this mental processing stage. Selection of the wrong memory schema may result in misinterpretation.
- Response selection and programming: the time necessary to decide which if any response to make and to mentally program the movement. (“I should steer left instead of braking.”) Response selection slows under choice reaction time when there are multiple possible signals. Conversely, practice decreases the required time. Lastly, electrophysiological studies show that most people exhibit preparatory muscle potentials prior to the actual movement. In other words, the decision to respond occurs appreciably faster than any recordable response can be observed or measured.
These four stages are usually lumped together as “perception time,” a misnomer since response selection and some aspects of situational awareness are decision, not perception.
Once a response is selected, the responder must perform the required muscle movement. For example, it takes time to lift the foot off the accelerator pedal, move it laterally to the brake and then to depress the pedal.
Several factors affect movement times. In general, more complex movements require longer movement times while practice lowers movement times. Finally the Yerkes-Dodson Law says that high emotional arousal, which may be created by an emergency, speeds gross motor movements but impairs fine detailed movements.
Device Response Time
Mechanical devices take time to engage, even after the responder has acted. For example, a driver stepping on the brake pedal does not stop the car immediately. Instead, the stopping is a function of physical forces, gravity and friction.
Here’s a simple example. Suppose a person is driving a car at 55 mph (80.67 feet/sec) during the day on a dry, level road. He sees a pedestrian and applies the brakes. What is the shortest stopping distance that can reasonably be expected? Total stopping distance consists of three components:
- Reaction Distance. First. Suppose the reaction time is 1.5 seconds. This means that the car will travel 1.5 x80.67 or 120.9 feet before the brakes are even applied.
- Brake Engagement Distance. Most reaction time studies consider the response completed at the moment the foot touches the brake pedal. However, brakes do not engage instantaneously. There is an additional time required for the pedal to depress and for the brakes to engage. This is variable and difficult to summarize in a single number because it depends on urgency and braking style. In an emergency, a reasonable estimate is .3 second, adding another 24.2 feet.
- Physical Force Distance. Once the brakes engage, the stopping distance is determined by physical forces (D=S²/(30*f) where S is mph) as 134.4 feet.
Total Stopping Distance = 120.9 ft + 24.2 ft + 134.4 ft = 279.5 ft
Almost half the distance is created by driver reaction time. This is one reason that it is vital to have a good estimate of speed of human response.
People brake faster when there is great urgency, when the time to collision is briefer. The driver is travelling faster and/or the obstacle is near when first seen. While brake times generally fall with greater urgency, there are circumstances where reaction time becomes very long when time-to-collision is very short. The most common situation is that the driver has the option of steering into the oncoming lane into order to avoid the obstacle. The driver then must consider alternative responses, braking vs. steering, weigh the dangers of each response, check the left lane for traffic, etc.
When other driving or nondriving matters consume the driver’s attention, then brake time becomes longer. For example, on a winding road, the driver must attend more to steering the car through the turns. Another major load on attention is the use of in-car displays and cell phones. There is no doubt that both cause delays in reaction times, with estimates ranging from 0.3 to as high a second or more, depending on the circumstances.
Humans have some highly built-in connections between percepts and responses. Pairings with high “stimulus-response compatibility” tend to be made very fast, with little need for thinking and with low error. Low stimulus-response incompatibility usually means slow response and high likelihood of error.
Psychological Refractory Period
Following a response, people exhibit a “psychological refractory period.” During this period, new responses are made more slowly than if there had been no previous behavior. For example, suppose a driver suddenly steers left and then right. The steer-right response will occur more slowly because it immediately followed the steer-left.
Although most basic research finds that older people respond slower than younger ones, the data on older drivers’ braking times are not entirely clear. One problem is that different studies have used different definitions of older; that is, sometimes “older means 50, sometimes it could mean 70.
Although the data are not clear, it seems likely that females respond slightly slower than males.
Nature of the Signal
In the examples cited above, the driver detected a distinct signal such as a brake light, the appearance of a clear obstacle in the path, etc. Some braking cues are subtler and more difficult to detect, causing slower braking times.
One of the most difficult situations occurs when a driver must detect motion of the car immediately ahead, its acceleration or deceleration. Accidents frequently occur because the driver fails to notice that the car ahead has stopped and does not apply brakes until it is too late.
Reaction time increases in poor visibility. Low contrast, peripheral viewing, bad weather, etc. slow response. Moreover, virtually all reaction time studies have been performed in high light, photopic visibility conditions. At night in urban areas, vision operates in the mesopic range, so there is mixed rod-cone activation. The few existing data suggest that reaction time sharply increases as the rods become the primary photoreceptor.
More complex muscular responses take longer. For example, braking requires lifting the foot from the accelerator, moving laterally to the brake pedal and then depressing. This is far more complex than turning the steering wheel. While there have been relatively few studies of steering reaction time, they find steering to be 0.15 to 0.3 second faster. Perception times are presumably the same, but assuming the hands are on the steering wheel, the movement required to turn a wheel is performed much faster than that required to move the foot from accelerator to brake pedal.
Reaction Time At Night
The same factors affecting reaction in daylight conditions operate at night. Light level per se, has little effect on reaction time. For example, one study found that under scotopic vision, decreasing light levels by a factor of ten only slowed reaction time by 20-25 msec (1/40 to 1/50 second.)
When driving, you are constantly searching the area immediately around your car, far ahead of your car, to the left, right, and rear for potential hazards. You’re looking at other vehicles and trying to determine what they’re doing, what they’re about to do, and what they may do. Lastly, you’re making adjustments to your speed and lane position based upon the information you’ve gathered. You may even activate some of the communication devices in your car. No, not your cell phone. By “communication devices”, we mean your turn signal, brake lights, head lights, and horn ( not your fingers and hands).
IPDE process are:
· I—Identify—Locate potential hazards within the driving scene.
· P—Predict—Judge where the possible points of conflict may occur.
· D—Decide—Determine what action to take, when, and where to take it.
· E—Execute—Act by maneuvering the car to avoid conflicts.
IPDE can help you avoid collisions.
I call the area immediately around the car and within 2-5 seconds of you the “instinctual range” because dangers that arise in this area require an immediate, instinctual reaction. You don’t have time to plan or think at this point. You must react quickly.
Your teen should be scanning this area approximately 50% of the time.
Scan and evaluate range
This is the area about 5-15 seconds ahead of your car. In this range, you have the time to make changes to your speed and lane position in order to minimize potentially dangerous situations. Essentially, you have the time to think, plan, and execute.
Your teen should be scanning this area approximately 35% of the time.
Long term range
Long term range is the area beyond 15 seconds ahead of your car. This long term range allows your teen ample time to evaluate different driving options as situations unfold. If your teen sees a car stopped in the middle of the road with its hazards on, they have time to check all of their space management zones to determine what course of action they should take.
Search, Identify, Predict, Decide and Execute (defensive driving method)
Scan, Identify, Predict, Decide, and Execute (defensive driving method)
You must be aware of the area surrounding your car. By dividing this space into different zones, you can easily search these areas. There are six zones and each zone is the width of a lane and extends as far as you can see: There are six zones and each zone is the width of a lane and extends as far as you can see:
- Left Front
- Right Front
- Left Rear
- Right Rear
Line of Sight Zone Changes. A red traffic light is a closed front zone , A motorcyclist to your right is a closed right zone . Oncoming traffic is a closed left zone . A vehicle following too closely is a closed rear zone .
Space management is the management of spaces – control and supervision of the physical spaces a business or organization occupies. This could be a single floor, multiple floors within a building, or multiple floors within multiple buildings. Space management is simple in concept yet far more complicated in practice.
“SEE”. This stands for Search, Evaluate, andExecute. It requires that you continuously search your surroundings, evaluate your changing driving environment, and execute necessary changes to your speed, lane position, and communication.
- Look at your front, left front, and right front zones 12-15 seconds ahead. Make sure you look for possible problem areas such as intersections or driveways.
- Check your rear zones.
- Check your front zone 4-6 seconds ahead for any immediate problems.
- Check your speed.
Remember to check each search area for a very short period of time. Your eyes should constantly be moving.
The next step is to evaluate each of the zones to determine which ones are open, closed, or changing.
Open zone: The zone has no restrictions to your line of sight or path of travel.
§ Your target area is the area 25-30 seconds ahead of you.
§ Your path of travel is the section of roadway that will get you from where you are to your target area.
§ Your line of sight is your ability to see the center of your path of travel from your car to your target area.
So, in other words, an “open zone” is one in which there’s nothing standing in the way of your car. Basically, the zone is clear of any obstacles, obstructions, or other cars.
Closed zone: Your path of travel is obstructed due to some condition (red light, construction, boulder in the road, etc). There may also be restriction to your line of sight. A closed zone indicates that you need to find an alternate path of travel.
Changing zone: This is most often an open zone that is changing into a closed zone. An example of this would be a yellow light at an intersection.
If you find a zone to be closed or changing, make sure you evaluate other zones for possible closed or changing conditions that might affect the action you wish to execute.
Executing requires that you adjust speed, determine lane position, and decide if communication is needed. These decisions should be based upon your evaluation. Remember that you will be making these adjustments continuously.
The safest place when driving is the place with the fewest cars. Try to keep as much space between you and the surrounding vehicles as possible. Other drivers might not always do the right thing. You should attempt to determine what other drivers are going to do and to leave space to escape if a dangerous situation arises.
Speed is your best friend when it comes to driving safely. If there is an obstacle in your path, a change in speed should be your first response. Don’t forget that your car will respond differently depending on the conditions of the road and the <condition of your tires>.
Some conditions which would require action are:
§ Traffic flow
§ Time of day
§ Traffic controls
§ Weather conditions
§ Lane width
§ Roadway conditions
§ Speed limits
By controlling your speed, you can control the space between your car and other cars or obstacles. If a car or obstacle moves dangerously close, you have the following options:
§ Continue at the same speed.
§ Increase your speed.
§ Reduce your speed.
§ Take your foot off the accelerator and cover the brake.
§ Take your foot off the accelerator and apply pressure to the brake pedal.
Lane Position Adjustments
Changing your position within the lane is a great way to avoid driving conflicts. Most of these lane position changes will be minor. For example, moving from the center of the lane to the left side of the lane to avoid a small pothole on the right side of the road.
By appropriately using communication, you make it easier for other drivers to see you. You also make it easier for you to see other drivers. Ensuring that you can see other drivers and that they can see you will drastically reduce the chance of an accident. The following communication devices are part of your “execution arsenal”:
§ Turn signals can be used to let other drivers know that you are turning, changing lanes, pulling out of a parking space or pulling out from the curb. You should signal at least four seconds before you plan to take action.
§ Hazard lights should be used to warn other drivers that you are experiencing car trouble. This is a warning to other drivers to give you more space.
§ The horn should be tapped lightly when trying to gain the attention of another driver or pedestrian. It should not be used to vent frustration at other drivers’ actions.
§ Headlights: Many new vehicles have daytime running lights that turn on automatically. These help other drivers see you. You can flash your lights to oncoming traffic to warn them of dangers up ahead such as accidents or obstructions in the roadway. They should not be used to warn other drivers of the location of police cars.