lecture 05 roundabout ( traffic engineering prof.usama shahdah )
TRANSCRIPT
![Page 1: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/1.jpg)
TRAFFIC ENGINEERING COURSE
(PWE 8322)
ROUNDABOUTS
Instructor: Usama Elrawy Shahdah, PhDLecture # 05
![Page 2: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/2.jpg)
Conflict Points2
![Page 3: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/3.jpg)
Conflict points3
![Page 4: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/4.jpg)
Geometric Characteristics
Entry width
Inscribed
circle
diameter
Exit width
Splitter island width
Circulatory roadway width
![Page 5: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/5.jpg)
Geometric Characteristics5
![Page 6: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/6.jpg)
6
![Page 7: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/7.jpg)
7
![Page 8: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/8.jpg)
Number of Lanes8
vc
va
![Page 9: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/9.jpg)
Roundabout Volumes
Turning
movements
Roundabout
volumes
![Page 10: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/10.jpg)
Steps
Vehicle TypePassenger Car
Equivalent (pce)
Car 1.0
Single-unit truck or bus 1.5
Truck with trailer 2.0
Bicycle or motorcycle 0.5
Step 1: Convert trucks and other vehicle types to
passenger car equivalents (pce)
Step 2: PHF volume adjustment
Step 3: Entry volume
Step 4: Exit volume
Step 5: Circulating volume
![Page 11: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/11.jpg)
Entry Volume
Entry volume = sum of entering turning movements
![Page 12: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/12.jpg)
Exit Volume
Exit volume = sum of turning movements as shown
![Page 13: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/13.jpg)
Circulating Volume
Circulating volume = sum of turning movements as
shown
![Page 14: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/14.jpg)
Example: Volume Conversion
Turning
movements
Roundabout
volumes
110350140
50240100
North/south:
4% SU trucks/buses, 2%
combo trucks
East/west:
2% SU trucks/ buses
?
PHF = 0.94
![Page 15: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/15.jpg)
Example Step 1: PCE Calculation
SB TH: 530 veh (4% SU/bus, 2% combo)% cars (0.94) 1.0 pce/veh = 0.94
% SU/bus (0.04) 1.5 pce/veh = 0.06
% combo (0.02) 2.0 pce/veh = 0.04
fhv = 1.04
530 veh
551 pceVehicle Type
Passenger CarEquivalent (pce)
Car 1.0
Single-unit truck or bus 1.5
Truck with trailer 2.0
Bicycle or motorcycle 0.5
![Page 16: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/16.jpg)
Example Step 1: Completed PCE
Calculation
Raw Counts PCEs
110350140
50240100 111
354141
51242101
![Page 17: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/17.jpg)
Example Step 2: PHF Factor
PCEs (hourly)PCEs (peak 15
minutes)
118377150
54258107111
354141
51242101
141 / 0.94 = 150
![Page 18: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/18.jpg)
Example Step 3: Calculate Entry
Volume
Entry volume = sum of entering turning movements
118377150
54258107 645
?
? 419
?
64
2
79
7
![Page 19: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/19.jpg)
Example Step 4: Calculate Exit Volume
Exit volume = sum of turning movements as shown
645
?
? 419
?
64
2
79
7
118377150
54258107
![Page 20: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/20.jpg)
Example Step 5: Calculate Circulating
Volume
Circulating volume = sum of turning movements as
shown
645
628
82
6
419
453
64
2
79
7
118377150
54258107
![Page 21: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/21.jpg)
Example: Solution
Turning
movements
Roundabout
volumes
110350140
50240100
North/south:
4% SU trucks/buses, 2%
combo trucks
East/west:
2% SU trucks/ buses
645
628
82
6
419
453
64
2
79
7
PHF = 0.94
![Page 22: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/22.jpg)
22
Capacity Determination
![Page 23: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/23.jpg)
HCM 2000 Method
CCCrrriiitttiiicccaaalll gggaaappp
(((ssseeeccc)))
FFFooollllllooowww---uuuppp
TTTiiimmmeee (((ssseeeccc)))
UUUppppppeeerrr---bbbooouuunnnddd
sssooollluuutttiiiooonnn
444...111 222...666
LLLooowwweeerrr---bbbooouuunnnddd
sssooollluuutttiiiooonnn
444...666 333...111
)3600/(
)3600/(
1 fc
cc
tv
tv
cae
evc
vc
va
![Page 24: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/24.jpg)
HCM method24
![Page 25: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/25.jpg)
CONTROL DELAY & LOS25
![Page 26: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/26.jpg)
Kimber Method26
Qe (capacity of entry flow) is linearly dependent
upon circulating flow crossing the entry (Qc).
![Page 27: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/27.jpg)
Kimber Method27
Factors affecting the capacity of a roundabout:
Inscribed circle diameter D (m)
width of flare of each entry. e (m),
Approach width v (m)
effective length over which flare is developed l' (m)
entry angle (φ)
entry radius (r) (m)
![Page 28: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/28.jpg)
Kimber Method28
![Page 29: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/29.jpg)
Kimber Method29
Range of geometric variables in data set used by
Kimber to develop capacity expression
![Page 30: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/30.jpg)
Kimber Method (simplified method)30
Single-lane roundabouts
This constraint implies that the capacity of the
circulating roadway of the roundabout is 1800 pcph.
![Page 31: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/31.jpg)
Kimber Method (simplified method)31
Two lane roundabouts
![Page 32: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/32.jpg)
Example32
A single-lane roundabout having the following geometric characteristics:
e = 4 m
v = 4 m
l’ = 40 m
r = 20 m
Φ = 30 degrees
D = 40 m
circulating volume = 285 pcph
the entry leg demand = 315 pcph.
Compute the average delay
Use an analysis period of 15 minutes.
![Page 33: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/33.jpg)
Solution33
Use Simplified Kimber method
Delay
![Page 34: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/34.jpg)
Trafficware Synchro34
Demonstrated in Class
![Page 35: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/35.jpg)
Home Reading35
Synchro Studio 9 User Guide
NCHRPREPORT 672 “Design Roundabouts: An
Informational Guide”, Second Edition
![Page 36: Lecture 05 Roundabout ( Traffic Engineering Prof.Usama Shahdah )](https://reader034.vdocument.in/reader034/viewer/2022042515/58711fb71a28abe4448b4bed/html5/thumbnails/36.jpg)
36
Thanks for your time