CEE 463/663 – Traffic Engineering
Fall 2006
Homework #1
Due: Tuesday, September 12, 2006
Problem 1: (Based on Problem 9-1 on Page 233 of the textbook)
Consider the following spot speed data, collected from a freeway site operating under
free-flow conditions (no congestion).
Speed Group, mph
15-20
20-25
25-30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
Number of vehicles
observided
0
3
6
18
45
48
18
12
4
3
0
(a) Plot the frequency and cumulative frequency curves for these data.
(b) Find and identify on the curves: median speed, modal speed, pace, percent
vehicles in pace
(c) Compute the mean and standard deviation of the speed distribution
(d) What is the 95% confidence interval of the true mean speed (review basic
statistics on how to calculate confidence intervals).
(e) Based on the results of this study, a second is to be conducted to achieve a
tolerance of ± 1.5 mph with 95% confidence. What sample size is needed?
CEE 463/663 – Traffic Engineering
Fall 2006
Problem 2.
Traffic flow rates measured upstream of a freeway bottleneck (free of queues) are shown
in the table below. Assume the freeway bottleneck has a capacity of 6400 vph. Calculate:
(1) Traffic demand, Measured flow rate downstream of the bottleneck, and Delay during
each interval. Indicate the units of each measure.
(2) What is the maximum queue length during the hour?
(3) Define the intervals when queue started and cleared.
Interval, min
4:00-4:05
4:05-4:10
4:10-4:15
4:15-4:20
4:20-4:25
4:25-4:30
4:30-4:35
4:35-4:40
4:40-4:45
4:45-4:50
4:50-4:55
4:55-5:00
Flow Rate (vph)
5000
6000
6100
6400
6600
7000
6800
6200
5800
5400
5000
4800
Problem 3.
Traffic volume counts were conducted at the intersection of Virginia Street/16th Street
between 7:30 a.m. and 10:00 a.m. on a typical weekday in 2003. Determine the
following:
(a) The PHFs for both the entire intersection and the westbound approach.
(b) Determine whether the intersection meets the MUTCD peak hour volume warrant.
CEE 463/663 – Traffic Engineering
TIME:
DATE:
PROJECT NO:
to
to
7:30 AM
to
10:00 AM
2/27/2003
9:45 AM
9:30 AM
J
K
INTERSECTION:
N. Virginia/16th
JURISDICTION:
City of Reno
PROJECT TITLE:
PEAK HOUR PERIOD:
8:45 AM
PEAK 15 MINUTE PERIOD:
9:15 AM
N. Virginia
Fall 2006
F
D
I
H
16th
N. Virginia
N
INTERSECTION
PEAK HOUR FACTOR:
RUNNING COUNTS
Period End
7:45 AM
8:00 AM
8:15 AM
8:30 AM
8:45 AM
9:00 AM
9:15 AM
9:30 AM
9:45 AM
10:00 AM
PERIOD COUNTS
Period End
7:45 AM
8:00 AM
8:15 AM
8:30 AM
8:45 AM
9:00 AM
9:15 AM
9:30 AM
9:45 AM
10:00 AM
HOURLY TOTALS
Beginning At
7:30 AM
7:45 AM
8:00 AM
8:15 AM
8:30 AM
8:45 AM
9:00 AM
.
Left
A
N/A
Eastbound
Thru
Right
B
C
16th
Westbound
Left
Thru
Right
D
E
F
0
0
4
5
6
8
6
9
6
10
8
12
11
13
11
15
13
15
18
16
N. Virginia
Northbound
Left
Thru
Right
G
H
I
129
4
219
12
309
30
405
43
494
47
609
55
757
61
883
71
980
74
1061
82
Left
J
7
23
30
35
38
39
47
73
79
87
N. Virginia
Southbound
Thru
Right
K
L
166
292
379
435
510
583
726
879
954
1033
TOTAL
306
555
762
933
1105
1306
1615
1932
2115
2297
A
B
C
D
0
4
2
0
0
2
3
0
2
5
E
F
0
5
3
1
1
2
1
2
0
1
G
H
129
90
90
96
89
115
148
126
97
81
I
4
8
18
13
4
8
6
10
3
8
J
7
16
7
5
3
1
8
26
6
8
K
166
126
87
56
75
73
143
153
75
79
L
TOTAL
306
249
207
171
172
201
309
317
183
182
A
B
C
D
6
6
4
5
5
7
10
E
F
9
10
7
5
6
5
4
G
H
405
365
390
448
478
486
452
I
43
43
43
31
28
27
27
J
35
31
16
17
38
41
48
K
435
344
291
347
444
444
450
L
TOTAL
933
799
751
853
999
1010
991