This activity requires the Edheads Crash Scene
Printout. If you don't already have one click here.
Please turn on speakers or plug in headphones.
You may turn audio off and on using the button in
the bottom right corner.
Printout. If you don't already have one click here.
Please turn on speakers or plug in headphones.
You may turn audio off and on using the button in
the bottom right corner.
CONTINUE
Skip Intro
Interact:
Use the view buttons below to see each side of this unit. Record any damage you see
by circling the appropriate description in the Damages Areas section, pages 2 and
3 of your printout. Once you have recorded the damage for both units press Continue.
by circling the appropriate description in the Damages Areas section, pages 2 and
3 of your printout. Once you have recorded the damage for both units press Continue.
Front
Left
Rear
Right
Top
left
right
left
right
CONTINUE
Logically, what's the best way to
proceed with this investigation?
proceed with this investigation?
Start at point of impact and determine
which skids and marks go with which car.
which skids and marks go with which car.
Start in the middle and then work in both
directions.
directions.
Start with what the eye witnesses told you.
Start from the final resting place and
trace skids and marks back to point of
impact.
trace skids and marks back to point of
impact.
Interact:
Find the Crash Scene
Diagram template on page 4
of your printout.
Diagram template on page 4
of your printout.
Make your own sketch of
skids, scrapes and evidence,
along with any labels
discussed on this sheet.
skids, scrapes and evidence,
along with any labels
discussed on this sheet.
When you're ready press
Continue.
Continue.
CONTINUE
Use your mouse to click any
skid marks or scrapes you
think were caused by Unit 1
If your skid or scrape shows
up in blue. you are correct. but
if it turns green it belongs to
Unit 2. When done take notes
on your diagram and press
Continue.
skid marks or scrapes you
think were caused by Unit 1
If your skid or scrape shows
up in blue. you are correct. but
if it turns green it belongs to
Unit 2. When done take notes
on your diagram and press
Continue.
CONTINUE
J
I
E
F
16 Feet
15 Feet
Measuring Tutorial
- Drag the first orange dot to the beginning of
the skid, over marker H. - Drag the middle orange dot to the center of
the skid to follow the curve. - Drag the last orange dot to the end of the
skid, over marker J.
Click Continue to try.
CONTINUE
With your mouse, grab each
orange dot on the measuring
tool, and place the tool over
skid mark H-J.
When done, press Continue.
orange dot on the measuring
tool, and place the tool over
skid mark H-J.
When done, press Continue.
Add up the two measurements
to get the total length of this
skid mark, and record the
information on your diagram
to get the total length of this
skid mark, and record the
information on your diagram
CONTINUE
Interact:
When done, press Continue.
Add up the two measurements
to get the total length of skid
mark J-I, and record the
information on your diagram.
to get the total length of skid
mark J-I, and record the
information on your diagram.
CONTINUE
Interact:
With your mouse, grab eachorange dot on the measuring
tool, and place the tool over
skid mark G-F.
When done, press Continue.
When done, record the
distance on your diagram and
press Continue.
distance on your diagram and
press Continue.
CONTINUE
Interact:
Which car do you think madescrape C? Click your answer
below:
Interact:
Click the mark in theintersection that you think is a
possible point of impact.
Interact:
Click any other marks or evidance near the impact
point that you think might be
important.
Having seen the location and
relative positions of the cars
after the accident, what do you
think this small mark might be?
relative positions of the cars
after the accident, what do you
think this small mark might be?
This is a skid from Unit 1 putting on its
brakes.
brakes.
This is a skid resulting from the right
rear tire of Unit 1 being pushed west.
rear tire of Unit 1 being pushed west.
This is a skid from the front left tire of
Unit 1 being pushed west.
Unit 1 being pushed west.
This is a skid from Unit 2 putting on its
brakes.
brakes.
It is fairly clear that the back
tires of Unit 2 did not leave skid
marks on the road. Why do you think that is the case?
tires of Unit 2 did not leave skid
marks on the road. Why do you think that is the case?
Both tires are bald so could not leave a
skid mark.
skid mark.
They are made from a new kind of rubber
that doesn't leave marks.
that doesn't leave marks.
They were new tires and would have kept
their tread instead of leaving it on the
road.
their tread instead of leaving it on the
road.
These tires were most likely still rolling
normally. therefore would not leave skid
marks.
normally. therefore would not leave skid
marks.
Skip Intro
Interact:
Questions will pause in
between to allow time for note
taking.
When you are ready press Continue.
Find pages 5 and 6 of your
Crash Scene printout.
Take down any important
information you hear from
each witness.
Crash Scene printout.
Take down any important
information you hear from
each witness.
CONTINUE
CONTINUE
CONTINUE
CONTINUE
CONTINUE
CONTINUE
CONTINUE
CONTINUE
CONTINUE
CONTINUE
You must ask all relevant
questions to continue.
questions to continue.
Click the question below you'd like to ask.
Where were you when the accident occurred?
What did you see?
Were there any obstructions in the road?
What color is the car you were driving?
Was there anything that prevented you from
seeing the green car?
seeing the green car?
What speed were you going?
What speed do you think the green car was
going?
going?
What happened after the crash?
What speed do you think the blue car was
going?
going?
Skip Intro
Interact:
Find the Officer's Notessection on page 10 of your
printout.
When you're ready press
Continue.
CONTINUE
Interact:
Find the Equations section onPage 8 of your printout.
When you're ready press
Continue.
CONTINUE
Interact:
Drag one end of yourmeasuring tool to Unit 1's
center of mass. and the other
end to the red arrow where
Unit 1 left the road.
Once you have your
measurement for distance(d).
write it down and press
Continue.
measurement for distance(d).
write it down and press
Continue.
CONTINUE
47 Feet
44 Feet
Average 40% and 100% to get percent braking (n) for this equation
Press Continue when done.
CONTINUE
30 X 0 X 0 X 0
0 miles per hour
CONTINUE
CONTINUE
Interact:
Drag one end of yourmeasuring tool to Unit 1's
center of mass. and the other
end to the red arrow where
Unit 1 stopped on the grass.
Once you have your
measurement for distance(d).
write it down and press
Continue.
measurement for distance(d).
write it down and press
Continue.
CONTINUE
Interact:
Once you are done pressContinue
Recard .45 as the drag factor
on grass for our variable (f)
on grass for our variable (f)
CONTINUE
20 Feet
19 Feet
30 X 0 X 0 X 0
0 miles per hour
CONTINUE
CONTINUE
CONTINUE
0 + 0
0 miles per hour
CONTINUE
CONTINUE
Why are we rounding down and using
the minimum post-collision speeds?
the minimum post-collision speeds?
To give the driver the benefit of the doubt.
So that a defense attorney can't argue that
we increased the speed by rounding up.
we increased the speed by rounding up.
Because that is the mathematically correct
thing to do.
thing to do.
To make it easier for a jury to understand
the math.
the math.
Interact:
When you are done press
Continue.
Write down the Approach
Angles for Unit 1(A1) and Unit
2 (A2) in the Worksheet
section of your printout.
Angles for Unit 1(A1) and Unit
2 (A2) in the Worksheet
section of your printout.
CONTINUE
2290
Interact:
Drag the orange dot to line upthe angle finder to the car's
red 'angle after impact' line.
Click Continue when ready
Once you have found the
Angle, write it down by (A3)
and (A4) in the Worksheet
section of your printout.
Angle, write it down by (A3)
and (A4) in the Worksheet
section of your printout.
CONTINUE
CONTINUE
CONTINUE
0 miles per hour
CONTINUE
CONTINUE
Write the answer for S2 down on page 9 of your printout.
Click Continue when done
Click Continue when done
0 miles per hour
Write the answer for S1 down on page 9 of your printout.
Click Continue when done
Click Continue when done
+
CONTINUE
CONTINUE
0 lbs of force
CONTINUE
CONTINUE
0 lbs of force
CONTINUE
CONTINUE
Force Results:
Drop the dummy from different
heights to see what forces of
impact are applied.
Press Continue when finished.
Drop the dummy from different
heights to see what forces of
impact are applied.
Press Continue when finished.
CONTINUE
Q: Is it likely that Unit 1 stopped at the stop sign?
Yes
No
Q: Is there any evidence that the driver of Unit 2 applied his
brakes before impact?
brakes before impact?
Yes
No
Q: Were there obstructions in the road or obstructions to
sight lines that could have contributed to this crash?
sight lines that could have contributed to this crash?
Yes
No
Q: What was the approximate distance that a west bound
driver, such as the driver of Unit 2, should have been able
to see a car entering the intersection as Unit 1 did?
driver, such as the driver of Unit 2, should have been able
to see a car entering the intersection as Unit 1 did?
150 feet
260 feet
380 feet
595 feet
Q: Tire analysis of the vehicles indicates that:
The accident could have been avoided with proper
inflation of tires
inflation of tires
Unit 1 had bald tires
All tires on both vehicles appeared to be in acceptable
condition
condition
Tire sizes were wrong for Unit 2 and should not have
been used
been used
Q: Analysis of the Crush Evaluation for Unit 1 indicates:
Glass shards were driven into passengers at impact
If the car met required safety standards, no one would
have died
have died
The seat belts of Unit 1 were faulty and did not hold the
passengers
passengers
The car met required safety standards for protecting
passengers
passengers
Q: The driver of Unit 2 reported that he was going 55 mph.
Do you agree with this statement?
Do you agree with this statement?
Yes
No
Q: If you were to charge one of the drivers with a violation,
which driver would it be?
which driver would it be?
Driver of Unit 1
Driver of Unit 2
Q: If you had to say that there was one primary contributing
factor to this accident, what was that factor?
factor to this accident, what was that factor?
Excessive speed
Driving under the influence
Passengers not wearing seat belts
Drivers not paying attention to weather and road conditions
Q: If there were lesser contributing factors to this accident,
what would you say they were?
what would you say they were?
Wet road conditions and fog
Posted speed limit and directional signs not being
clearly visible
clearly visible
Utility pole and vegetation blocking view of other traffic
for both drivers
for both drivers
Evidence that the driver of Unit 2 looked down at the
wrong moment
wrong moment
Q: Two of the three people in Unit 1 died within seconds of
the accident. The third died shortly thereafter. There was
some blood on the scene, but not enough to account for
the deaths. What killed these three people?
the accident. The third died shortly thereafter. There was
some blood on the scene, but not enough to account for
the deaths. What killed these three people?
They went into medical shock (blood pressure dropped)
The car crushed them
The force of the collision was sufficient to damage
internal organs and impair brain function
internal organs and impair brain function
They did bleed to death, but the blood soaked into the
ground
ground
Q: The two people in Unit 2 both survived. Why did they not
die as the people in Unit 1 did?
die as the people in Unit 1 did?
The people in Unit 2 saw what was happening and were
able to prepare themselves for the impact.
able to prepare themselves for the impact.
Unit 2 continued in the direction it was initially going
after impact. The crushing forces would not have been
nearly as high as those for Unit 1.
after impact. The crushing forces would not have been
nearly as high as those for Unit 1.
The people in Unit 2 jumped out of the car just
before impact, rolling away to safety.
before impact, rolling away to safety.
Their much higher body weight made them better able
to handle the forces of the impact.
to handle the forces of the impact.
Some questions can be answered by reviewing the Officer's Notes section in your printout, pages 10 through 13.
WHAT IF?
mph
55 mph
On the speed test course, we will recreate the accident already investigated, with Unit 1 being the blue car and Unit
2 being the green car, to show how speed played such a devastating role. Using the following simulation, test the
reaction time of the green car at different speeds.
The speed limit is 55 mph. What do you think will happen if we obey or break that speed limit?
Grab the slider to set the speed our test driver will be driving. Then press 'GO' to start!
2 being the green car, to show how speed played such a devastating role. Using the following simulation, test the
reaction time of the green car at different speeds.
The speed limit is 55 mph. What do you think will happen if we obey or break that speed limit?
Grab the slider to set the speed our test driver will be driving. Then press 'GO' to start!
270 feet to point of impact
VeloCity = ?
Thinking Distance = ?
Braking Distance = ?
Regardless of the speed of the green car, the distance to the point of impact with the blue car will remain the same
at 270 feet. Click 'Continue' when done.
at 270 feet. Click 'Continue' when done.
CONTINUE
Your first task is to convert Speed in miles per hour to Velocity
in feet per second. Type the speed of the green car into the
equation on the right to calculate its velocity.
Click 'Continue' when done.
in feet per second. Type the speed of the green car into the
equation on the right to calculate its velocity.
Click 'Continue' when done.
0 fps
CONTINUE
It takes time to realize something is wrong and then react to it
while driving. The average reaction time is around 1.75
seconds for most unimpaired drivers. The Thinking Distance
is the distance the vehicle travels in the time it takes the driver
to react to a situation. Using the equation on the right, enter
the Velocity of the green car and the reaction time of 1.75
while driving. The average reaction time is around 1.75
seconds for most unimpaired drivers. The Thinking Distance
is the distance the vehicle travels in the time it takes the driver
to react to a situation. Using the equation on the right, enter
the Velocity of the green car and the reaction time of 1.75
0 fps
CONTINUE
Now calculate how far the green car would take to brake to a
stop at our speed of 55 mph. Complete the Braking Distance
equation to the right using 55 mph, a drag factor of 0.71 and
a braking factor of 1 Click 'Continue' when done.
stop at our speed of 55 mph. Complete the Braking Distance
equation to the right using 55 mph, a drag factor of 0.71 and
a braking factor of 1 Click 'Continue' when done.
0 feet
CONTINUE
CONTINUE
MENU
55 mph
95 lbs
Seat belts prevent deaths, but don't take our word for it - check out the math and science for yourself! This
simulation will allow you to set up your own accident to show the force and injury sustained with various outcomes.
First drag the speed slider to set our speed at impact in miles per hour. Next drag the weight slider to change the
weight of the driver. Finally, put seatbelts on or take seatbelts off. When you're ready press 'GO' to watch the
accident.
simulation will allow you to set up your own accident to show the force and injury sustained with various outcomes.
First drag the speed slider to set our speed at impact in miles per hour. Next drag the weight slider to change the
weight of the driver. Finally, put seatbelts on or take seatbelts off. When you're ready press 'GO' to watch the
accident.
CONTINUE
MENU
Speed = 0 mph
Velocity = 80 fps
Driver's Weight = 0 lbs
Seatbelt = OFF
DRUNK
SOBER
55 mph
Driver is SOBER
320 feet to point of impact
VeloCity = ?
Thinking Distance = ?
Braking Distance = ?
On the alcohol test course, we will test out how drinking alcohol effects driving response time.
The green car is obeying the speed limit, going 55 mph. You decide if the driver is drunk or sober to see
how drinking can effect reaction time.
When you're ready press 'GO' to start!
The green car is obeying the speed limit, going 55 mph. You decide if the driver is drunk or sober to see
how drinking can effect reaction time.
When you're ready press 'GO' to start!
The distance to the stop sign and intersection will remain the same at 320 feet. Click 'Continue' when done.
CONTINUE
Your first task is to convert Speed in miles per hour to Velocity
in feet per second. Type the speed of the green car into the
equation on the right to calculate its velocity.
Click 'Continue' when done.
in feet per second. Type the speed of the green car into the
equation on the right to calculate its velocity.
Click 'Continue' when done.
0 fps
CONTINUE
It takes time to realize something is wrong and react to it.
This time is much longer for an impaired driver. The Thinking
Distance is the distance the vehicle travels in the time it takes
the driver to react to a situation. Using the equation on the right,
enter the Velocity of the green car and the reaction time of 2.5
seconds for a legally drunk driver to perceive and react. It takes time to realize something is wrong and then react to it
while driving. The average reaction time is around 1.75
seconds for most unimpaired drivers. The Thinking Distance
is the distance the vehicle travels in the time it takes the driver
to react to a situation. Using the equation on the right, enter
the Velocity of the green car and the reaction time of 1.75
This time is much longer for an impaired driver. The Thinking
Distance is the distance the vehicle travels in the time it takes
the driver to react to a situation. Using the equation on the right,
enter the Velocity of the green car and the reaction time of 2.5
seconds for a legally drunk driver to perceive and react. It takes time to realize something is wrong and then react to it
while driving. The average reaction time is around 1.75
seconds for most unimpaired drivers. The Thinking Distance
is the distance the vehicle travels in the time it takes the driver
to react to a situation. Using the equation on the right, enter
the Velocity of the green car and the reaction time of 1.75
0 fps
CONTINUE
Now calculate how far the green car would take to brake to a
stop at our speed of 55 mph. Complete the Braking Distance
equation to the right using 55 mph, a drag factor of 0.71 and
a braking factor of 1 Click 'Continue' when done.
stop at our speed of 55 mph. Complete the Braking Distance
equation to the right using 55 mph, a drag factor of 0.71 and
a braking factor of 1 Click 'Continue' when done.
0 feet
CONTINUE
CONTINUE
MENU
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