Transcript Lecture 8 - Diamond Interchanges

Topic 8
Diamond Interchanges
CEE 764 – Fall 2010
At Grade Interchange Types



Diamond Interchange (>70%)
Partial Cloverleaf
Single-point Urban Interchange (SPUI)
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Diamond Interchange



Tight Diamond (<400 ft)
Compressed (400~800 ft)
Conventional (>800 ft)
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SPUI
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Partial Cloverleaf
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Diamond Interchange
Standard Intersection
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Diamond Interchange
Signal Phases at a Diamond Interchange
4
A=1 + 2
1
2
6
5
B=5 + 6
+2
Diamond Signal
8
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Basic Three-Phase Operation
ф5
ф5
Traffic Progression Line
A
A
B
B
ф1
ф6
ф2
B
ф4
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ф6
A
Time
A
TT
ф2,1
8
B
TT
4 1,2
Distance
Time
ф1
ф8
Phase Split and Capacity
Basic Three Phase
1  2  4  C
 5   6  8  C
g 4  g 8  max[
y4
y8
 ( C  3l ),
 ( C  3l )]
y1  y2  y4
y5  y6  y8
 yi
 y  y  ( C  g 4  3l ), for i  1,2
 1
2
gi  
 yi  ( C  g  3l ), for i  5 ,6
8
 y5  y6
CEE 764 – Fall 2010
Example: Three Phase
440
950
600
930
125
575
300
+2
740
CEE 764 – Fall 2010
Example: Three Phase
Movement
Demand
vph
Sat. Flow
vph
Flow Ratio
1
600
1700
0.35
2
300
3600
0.08
4
440
5400
0.08
5
125
800
0.16
6
930
3600
0.26
8
740
5400
0.14
1+2
950
3600
5+6
575
3600
CEE 764 – Fall 2010
Phase
Time, sec
Capacity
vph
v/c Ratio
Time
Other Three Phase
Favor West Side
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Time
Other Three Phase
Favor East Side
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TTI-4 Phase
Φ (12)
4=’4 + Φ
’4
A=1 + 2
1
2
6
5
B=5 + 6
+2
Diamond Signal
’8
Φ (16)
8=’8 + Φ
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TTI-four-Phase Operation
Traffic Progression Line
A
ф1
ф1
B
ф44
ф5
A
Overlap
ф88

ФФ8
ф5
ф2
A = ф1 + ф2
B = ф5 + ф6
CEE 764 – Fall 2010
B
ф4
A
Distance
8 = 8 + Ф
4 = 4 + Ф
Ф4
B
ф2
ф6
Time
Ф
Ф4
Time
Overlap
A
B
Ф
Ф8
Overlap
* Overlap = T.T. - 2
Phase Split and Capacity
Four Phase
2  4  6  8  C      C  2
1  5  C  2
1   2   4  5   6  8  2C
1  2  4  5  6  8  C
gi 
yi
y
 (C  2  4l )  i  (C  2  4l ),
y 2  y 4  y 6  y8
Y
g1  C   2   4  l
g 5  C   6  8  l
CEE 764 – Fall 2010
for i  2,4,6,8
Example: Four Phase
440
950
600
930
125
575
300
+2
740
CEE 764 – Fall 2010
Example: Four Phase
Movement
Demand
vph
Sat. Flow
vph
Flow Ratio
1
600
1700
0.35
2
300
3600
0.08
4
440
5400
0.08
5
125
800
0.16
6
930
3600
0.26
8
740
5400
0.14
1+2
950
3600
5+6
575
3600
CEE 764 – Fall 2010
Phase
Time, sec
Capacity
vph
v/c Ratio