Radar Speed Gun Handout4
L
Data collection is recorded at all selected locations based on recommendations
from schools. Due to the geography of local streets, some schools may not
recommend any streets.
A preliminary survey of car speeds will be made at each location. Locations that
do not have significant speeding (greater than 5 mph above the limit) will be
dropped from the list of streets for data collection.
Data will be collected from both directions that approach the school. In
consultation with the schools and Sheriff Department, a decision to collect from
only one direction may be made if the predominate number of cars or the high
speed only comes from one direction.
Data collection times:
® In the morning, data collection begins at the time the playground is open and
will continue for 15 minutes after the school bell rings to start school.
® In the afternoon, data collection begins 10 minutes before the school bell that
ends school and continues until 15 minutes after the school bell ends school
(at elementary schools, the afternoon data collection will be 55 minutes,
except on Tuesdays.)
Data collection duties:
® Radar gun operator — uses the radar gun to determine the speed of
approaching cars, also counts the number of cars that are closely following
the measured car.
® Data recorder — records the measured speed and the number of cars
travelling at that speed on the data collection form.
Data analysis:
® The recorded data are entered into a Microsoft Excel data sheet (same form
as used to record the measured data)
® The Excel data sheet presents the measured data as histograms of the speed
and number of cars. The formulas in the Excel data sheet calculate the total
number of cars that were observed, the averages speed of the cars and the
standard deviation of the measured speed of all cars.
Data collection schedule:
® Data should be collected at least two times at each location and both in the
morning and afternoon. If there are 20 streets selected, this results in 160
data collections if traffic in both directions is collected.
Radar Speed Gun Data Procedure.doc
School: Lincoln Location: McClellan at Imperial (W) ®ate: June 9, 2009
Min.
Sec
# of Cars
Speed
r
Min.
Sec
# of Cars
Speed
8:45
0
18
36
8:35
0
4
28
10
10
20
20
30
2
29
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30
2
32
40
1
30
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40
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50
8:36
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2
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8:46
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1
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50
50
8:37
0
5
29
8:47
0
19
36
10
10
20
2
30
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1
33
30
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1
34
40
1
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40
50
1
35
50
8:38
0
1
33
8:48
0
3
31
10
10
2
34
20
20
30=:
30
2
31
40
40
50
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50
3
32
8:39
0
10
31
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0
27
31
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20
30
30
1
35
40
3
36
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40
50
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32
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8:40
0
8:50
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10
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40
40
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8:41
0
14
29
8:51
0
25
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50
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0
16
30
; 8:53
0
17
30
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20
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20
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34
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School: Lincoln
Location: McClellan at Imperial (W) Date: June 9, 2009
30
25
20
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40
35
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0
A.M. Car Traffic at Lincoln School - Before Bell
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8:35 8:37 8:39 8:41 8:43 8:45 8:47 8:49 8:51 8:53
Arrival Time
A.M. Car 'traffic a4 Lincoln School - Before Bell
0 Car Speed
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8:35 8:37 8:39 8:41 8:43 8:45 8:47 8:49 8:51 8:53
Arrival Time
Total Cars before Sell:
244
Average Speed:
32.1
Standard Deviation:
2.1