CE 474
Traffic Systems Design
Fall 2006
Homework #3
Objectives
 Design a detector location for an advanced detector
 Describe how an intersection operates using basic signal terminology
Due: Wednesday, 8/30/06 at the beginning of class.
(1) Design the location of an advanced detector for an actuated signalized
intersection approach. The detector is 6 ft long and the average approach speed is
40 mph. Assume there is no stop bar detection, an 18 ft vehicle length, and the
distribution of headways is the same as the data used in Lab #1. (find (X)
X
(2) Design the location of an advanced detector for an actuated signalized
intersection approach. The detector is 6 ft long and the average approach speed is
40 mph. Assume there is no stop bar detection, an 18 ft vehicle length, and the
desired maximum allowable headway for the corresponding phase is 5 seconds.
(find X)
X
(3) Determine the passage time for a phase served by an advanced detector located as
shown in the figure below. There is no stop bar detection, the detector is 12 ft
long, vehicles are 18 ft long, and the average approach speed is 35 mph. What
ramifications does this detector location have on intersection efficiency?
254 ft
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CE 474
Traffic Systems Design
Fall 2006
Homework #3
(4) Describe the operations of the 6th street and Deakin Avenue intersection using the
basic signal terminology that we covered in class. Use all of the terms correctly
and to the fullest extent possible.
a. Create an electronic plan view of the intersection to show the intersection
geometry, signal masts and mast heads, signal indications, vehicle turning
movements, and crosswalks.
b. Define the phase and phase sequence using a NEMA phase diagram,
modified to only include protected turning movements that exist at the
intersection.
c. Time and illustrate the intervals for a typical sequence of phases using a
time line. If there is a specific term for the type of interval then use it on
the illustration. Your illustration should look similar to the following
diagram.
3
R (Clearance
Int.) phase 4
4
R (Clearance
Int.) phase 8
22
Y (change
int.) phase 4
3
Y (change
int.) phase 8
4
G phase 4
10
G phase 8
3
R (Clearance
Int.) Phase 2
4
R (Clearance
Int.) phase 6
8
Y (change
int.) phase 2
3
Y (change
int.) phase 6
4
G phase 2
15
G phase 6
12
R (Clearance
Int.) phase 1
11
G phase 6
10
Y (change
int.) phase 1
9
G phase 6
8
G phase 1
7
G phase 6
6
G phase 1
5
R (Clearance
Int.) phase 5
4
G phase 1
3
Y (change
int.) phase 5
2
G phase 1
1
G phase 5
Interval
number
Time (sec)
Ring 1
Ring 2
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