roundabout design and cappyacity analysis in … · this presentation highlights various aspects of...
TRANSCRIPT
Roundabout Design and Capacity g p yAnalysis in Australia and New Zealand
International Roundabout Design and Capacity Seminar6th International Symposium on Highway Capacity and6th International Symposium on Highway Capacity and Quality of Service, Stockholm, Sweden, 1 July 2011Presenter: Rahmi AkçelikPresenter: Rahmi Akç[email protected]
© Copyright 2000‐2011 Akcelik & Associates Pty Ltd
The objective of presentationj p
This presentation highlights various aspects of roundabouts inThis presentation highlights various aspects of roundabouts in AUSTRALIA and NEW ZEALAND in response to the following objective of the International Roundabout Design and Capacity Seminar:
Present an overview of typical roundabout designs in urban and rural environment and treatments of bicycles and pedestrians, capacity and level of service methods used and recent research on capacity andlevel‐of‐service methods used, and recent research on capacity and level‐of‐service.
This is by no means a complete account of the subject For more detailedThis is by no means a complete account of the subject. For more detailed information, please see the publications referred to in the presentation as well as other papers and presentations available for download from:
www.sidrasolutions.com/software_downloads_articles.aspx
Also refer to related guidelines used in Australia and New Zealand.
2 of 61
ACKNOWLEDGEMENTS
AUSTRALIA
VicRoads: Douglas Harley, Matthew Hallg y
Queensland Department of Transport and Main Roads: Owen Arndt, David Stewart, Robyn Davies, Mark McDonaldy
NEW ZEALAND
ViaStrada: Axel WilkeTraffic Engineering Solutions: Ivan Jurisichg g
3 of 61
Australia And New Zealand
• We drive on the left‐hand side of the road.• Private car ownership is very high.• Road use by commercial vehicles is substantial• Road use by commercial vehicles is substantial.• Traffic congestion due to limited road space is
a problem in large cities.• Roundabouts are common and there are many.
high‐capacity roundabouts.
4 of 61
All-Way Stop Control is rareTwo Way Give Way (Yield) Control is commonTwo-Way Give Way (Yield) Control is common
Thi i lik l t ff t it f d b tThis is likely to affect capacity of roundabouts
USA
Australia & UKAustralia & UK
5 of 61
Roundabout designRoundabout design
6 of 61
AUSTROADS (2009) Guide to Road Design Part 4B ROUNDABOUTSPart 4B ‐ ROUNDABOUTS
New Roundabout Guide
(replaces the 1993 AUSTROADS Guide to(replaces the 1993 AUSTROADS Guide to Traffic Engineering, Part 6)
7 of 61
Roundabout examples – lane markingsp g
8 of 61
Roundabout examples – lane markingsp g
9 of 61
Roundabout examples – lane markingsp g
10 of 61
Roundabout examples – lane markingsp g
11 of 61
Roundabout examplesp
12 of 61
Roundabout examplesp
13 of 61
Roundabout examples – bus bypass lanesp yp
14 of 61
Roundabout lane markingsg
15 of 61
Roundabouts in Australia –a survey of Australian professionals
Akçelik R (2008) Roundabouts in Australia Paper presented at theAkçelik, R. (2008). Roundabouts in Australia. Paper presented at the National Roundabout Conference, Transportation Research Board, Kansas City, MO, USA, 18‐21 May 2008.
O ll t d i t l d b t ith i l th
Replacing signals with roundabouts or roundabouts with signals?
Overall trend is to replace roundabouts with signals rather than the other way round. The reasons given include:
d b t it li it tiroundabout capacity limitationsunbalanced flow situationsbetter allowance for road users such as pedestrians and cyclists.
16 of 61
Roundabouts in Australia –a survey of Australian professionals
A respondent commented: “Some see roundabouts as anA respondent commented: Some see roundabouts as an evolutionary step before signals. A saturated signalised intersection is often treated through the construction of extra e sec o s o e ea ed oug e co s uc o o e alanes, slip lanes and so on, rather than considering the option of a roundabout.”Replacing a roundabout with signals due to capacity reasons applies particularly to two‐lane roundabouts since it is not common to expand them to three‐lane roundabouts to improve capacity (although it occasionally happens).
17 of 61
Bicycle and pedestrian treatment examples
18 of 61
Bicycle and pedestrian treatments
Refer to: AUSTROADS (2009) Guide to Road Design, Part 4B – ROUNDABOUTS, Section 5.
y p
( ) gThis guide carries many warnings about possible treatments.
The official New Zealand Transport Agency guidance is not to use cycle lane markings within the roundabout. Refer to the New Zealand training material “Planning and Design for Cycling, Module 4, Section 4 – Roundabouts”: http://viastrada.co.nz/sites/viastrada.co.nz/files/Module4‐section4.pdf
19 of 61
Bicyle treatment examplesy p
Australia
20 of 61
Bicyle treatment examplesy p
Australia
21 of 61
Bicycle treatment examplesy p
New ZealandNew Zealand
22 of 61
Bicycle treatment examplesy p
New Zealand
23 of 61
New Zealand – The C‐Roundabout
Paper by Ivan Jurisich presented at the TRB Roundabout Conference Carmel INPaper by Ivan Jurisich presented at the TRB Roundabout Conference, Carmel, IN, USA, May 2011. For further information contact: [email protected]
VIDEOS are available.
Also refer to:Also refer to:Multi‐lane roundabout designs for cyclists. New Zealand Transport AgencyZealand Transport Agency, Research Report 287. Wellington, New Zealand, 2006.2006.www.nzta.govt.nz/resources/research/reports/287
24 of 61
New Zealand – The C‐Roundabout
25 of 61
Capacity and Level of Service Methods
26 of 61
Capacity and Level of Service Methodsp y
In Australia and New Zealand practice, SIDRA INTERSECTION software is the main method used for capacity, performance p y, pand level of service.
Information about the roundabout capacity model used in o at o about t e ou dabout capac ty ode usedSIDRA INTERSECTION is given in the following slides.
27 of 61
Features of SIDRA INTERSECTION
Model CONSISTENCY in evaluating alternative intersectionModel CONSISTENCY in evaluating alternative intersection treatments (e.g. Definition of delay, back of queue, stops, etc).
Total intersection analysis toolanalysis tool
28 of 61
SIDRA models for LOCAL CONDITIONS
SIDRA INTERSECTION provides facilities to calibrate the traffic model for local traffic
diticonditions:
• Standard models with various options are available for different countries.are available for different countries.
• Customised Models can be prepared by users.
• Various options and key input parameters can be used for detailed calibration.
HCM 2010 d b t it d l• HCM 2010 roundabout capacity model is fully integrated into the software.
29 of 61
Features of SIDRA INTERSECTION
Power‐based fuel and emission model
Distance
Four‐mode elemental model (drive cycles)• Emissions ‐ CO2 CO HC NOx• Emissions ‐ CO2, CO, HC, NOx• Fuel consumption• Operating COST
Time
p g
Speed
Time
30 of 61
Features of SIDRA INTERSECTION
Approach‐based models such as the UK (TRL) linear
more detailed model of traffic stream
Approach based models such as the UK (TRL) linear regression (“empirical”) model for roundabouts are not adequate for intersection analysis
Individual vehicles
Microsimulation models
Drive cycles
SIDRA cycles
INTERSECTION
Traffic flows
RODEL, ARCADY TRANSYT, SYNCHROUS Highway Capacity Software
Micro‐analytical model
Speed‐flow functions
Most transport planning and economic analysis models
Approaches Lane groups Individual LANES
more detailed model of road geometryLEVEL OF ANALYSIS DETAIL
31 of 61
ROUNDABOUT MODELS in SIDRA INTERSECTION
32 of 61
Papers presented at the International Roundabout Conference, Transportation Research Board Carmel Indiana USA May 2011Transportation Research Board, Carmel, Indiana, USA, May 2011
• Some common and differing aspects of alternative models for roundaboutSome common and differing aspects of alternative models for roundabout capacity and performance estimation
• An Assessment of the Highway Capacity Manual 2010 Roundabout Capacity Model
Table comparing the features three well‐known analytical models of roundabout capacity:
USA: HCM 2010 (Highway Capacity Manual 2010) model
Australia: SIDRA INTERSECTION model, and
UK: TRL (linear regression) model (RODEL /ARCADY). ( g ) ( / )
These models have some common features as well as significant differences.
33 of 61
LANE – BASED methodLANE BASED method
Short lane analysis
• Lane flows• Unequal lane use
(flaring)
• Unequal lane use• De facto exclusive lanes• Approach short lanespp• Exit short lanes (lane use effects)• Roundabout circulating lane use
Effectiveness of flaring (shortEffectiveness of flaring (short lanes) depends on flow conditionsThese cannot be modelled using an
APPROACH‐BASED method
34 of 61
Observed at UK Roundabouts
Lane use at flared approachesLane use at flared approaches (short lanes) depends on flows
Unequal lane utilisation
These cannot be modelled using an APPROACH‐BASED method
35 of 61
Observed at UK Roundabouts
Continuous lane without island causingContinuous lane without island causing lane underutilisation on another approach
This cannot beThis cannot be modelled using an APPROACH‐BASED method
36 of 61
Observed at UK Roundabouts
Mini roundabouts operate effectively as all‐way give‐way controlMini roundabouts operate effectively as all way give way control
37 of 61
SIDRA INTERSECTION features
Follow‐up Headway and Critical Gap values decrease with increased GEOMETRY and DRIVER BEHAVIOUR
flow rates, and depend on roundabout geometry
4.0 Di = 30 ne = 18.0
Di 30 1
2.5
3.0
3.5
up h
eadw
ay (s
) Di = 30, ne = 1
Di = 50, ne = 2
Di = 80, ne = 3
More capacity
5.0
6.0
7.0
tical
gap
(s)
Di = 30, ne = 1
Di = 50, ne = 2
Di = 80, ne = 3More capacity
1.0
1.5
2.0
nant
lane
follo
w-
2.0
3.0
4.0
omin
ant l
ane
crit
0.0
0.5
0 300 600 900 1200 1500 1800 2100 2400 2700
Dom
in
Circulating flow (pcu/h)
0.0
1.0
0 300 600 900 1200 1500 1800 2100 2400 2700
Do
Circulating flow (pcu/h)
38 of 61
SIDRA INTERSECTION features
GEOMETRY parameters that affect capacity• inscribed diameter• number of entry lanes
GEOMETRY parameters that affect capacity
number of entry lanes• average entry lane width• number of circulating lanes• entry radius• entry angle• “flaring” as short lanes• flaring as short lanes• bypass (slip and continuous) lanes
39 of 61
SIDRA INTERSECTION features
FLOW parameters that affect capacity• circulating flow rate: increased values decrease the follow‐up headway and critical gap
FLOW parameters that affect capacity
increased values decrease the follow up headway and critical gap• circulating stream bunching characteristics (circulating lane flows)• origin‐destination flow patterns and queuing on approach lanes (for modelling unbalanced flow conditions)
• ratio of arrival flow to circulating flow• ratio of dominant lane flow rate to subdominant lane flow rate• ratio of dominant lane flow rate to subdominant lane flow rate• heavy vehicles in the entry lane and circulating lane• Environment Factor (general calibration parameter)(g p )
40 of 61
SIDRA INTERSECTION features
SIDRA INTERSECTION models negotiation radius, speed Roundabout model – LOW DEMAND
g , pand distance allowing for path smoothing by drivers
41 of 61
SIDRA INTERSECTION features
SIDRA INTERSECTION identifies congestion caused by heavy Roundabout model – HIGH DEMAND
circulating flows especially with UNBALANCED flow patterns
Roundabout Metering Signals
42 of 61
SIDRA aaSIDRA SIDRA INTERSECTION
• First released in 1984• First released in 1984• SIDRA INTERSECTION 5.1 released two months ago
43 of 61
SIDRA NETWORK >> SIDRA INTERSECTION 6.0
• Backward spread of congestion (queue blockage)• Capacity constraint
44 of 61
SIDRA interlinking with major software packages g j p g
VISUMT f S l i VISUMTransoft Solutions
VISSIM
45 of 61
SIDRA INTERSECTION Users
1979
2634
559
USA
Australia
South Africa
407
284
80
USA
Australia
South Africa 559
316
406
159
356
Sout ca
Canada
New Zealand
Arabian Peninsula
Malaysia
80
70
49
48
40
Canada
Arabian Peninsula
New Zealand
Malaysia
88
32
171
165
31
Slovenia
Spain
Singapore
Norway
It l
31
19
18
16
15
Slovenia
Spain
Singapore
Norway
It l
Over 7700 Licences U i 5 1 5 0 4 0 d 3 U O l
Over 1200 Organisationsin 67 Countries 31
58
411
133
134
Italy
Chile
Turkey
Other Asia and Africa
Other Europe
15
10
6
44
45
Italy
Chile
Turkey
Other Asia and Africa
Other Europe
Unique 5.1, 5.0, 4.0 and 3.x Users Only (23 June 2011)
in 67 CountriesLatest Version 5.1, 5.0, 4.0 and 3.x Users Only (23 June2011)
134
87
Other Europe
Other Latin America
45
23
Other Europe
Other Latin America
46 of 61
New ResearchNew Research
47 of 61
Entry Radius and Entry Angle i SIDRA S d d d l (SIDRA INTERSECTION 5 1)in SIDRA Standardmodel (SIDRA INTERSECTION 5.1)
fr = 0.95 + 1 / re
f 0 94 0 00026 / φ 1 6fa = 0.94 + 0.00026 / φe1.6
re is the entry radius (m) φe is the entry angle (degrees) φe y g ( g )Customary units: fr = 0.95 + 3.28 / rere is the entry radius (ft)
48 of 61
e y ( )
Roundabout Size: Inscribed Diameter
SIDRA Standard model UK TRL model (RODEL, ARCADY)
2000
2100
y (v
eh/h
)
1800
1900
proa
ch c
apac
ity
Capacity drops for very large Capacity does not
1600
1700
Tota
l app
y groundabouts
p ydrop
20 40 60 80 100 120 140 160 180 200Inscribed diameter (m)
49 of 61
Model calibration issue with the TRL model (RODEL ARCADY)(RODEL, ARCADY)
A “fatal flaw”: when the y‐intercept is fixed:
Capacity decreases withCapacity decreases with improved geometry (increased entry radius, decreased entry angle etc)decreased entry angle, etc) if the capacity at zero circulating flow (y i t t) i fi dintercept) is fixed.
Refer to: LENTERS, M. and RUDY, C. (2010). HCM Roundabout Capacity Methods and Alternative CapacityMethods and Alternative Capacity Models. ITE Journal, 80 (7), pp. 22‐27.
50 of 61
Roundabout Metering Signals CASE STUDY: Nepean Hwy – McDonald St, Melbourne, Australia, AM Peak
AKÇELIK, R. (2011). Roundabout metering signals:Metered Approach: AKÇELIK, R. (2011). Roundabout metering signals: capacity, performance and timing. Paper presented at the 6th International Symposium on Highway Capacity and Quality of Service, Transportation R h B d St kh l S d
Metered Approach: McDonald St
Research Board, Stockholm, Sweden.
Controlling Approach: Nepean Hwy SENepean Hwy SE
51 of 61
Metering Signals Project : Akcelik & Associates for VIC ROADSAkcelik & Associates for VIC ROADS
A j j t d t k b Ak lik & A i t fA major project was undertaken by Akcelik & Associates for VIC ROADS, the state transport authority in Victoria, to investigate the performance of roundabouts with metering signals inthe performance of roundabouts with metering signals in Melbourne, Australia.
The project included comprehensive surveys of traffic and driverThe project included comprehensive surveys of traffic and driver behaviour at roundabouts with metering signals.
Twenty roundabouts with metering signals were considered asTwenty roundabouts with metering signals were considered as candidates for the project. Five multi‐lane roundabout sites were chosen for surveys (1 to 3 circulating lanes).
The peak 15‐min intersection volumes at these sites were in the range approximately 3300 to 6000 veh/h.
52 of 61
g pp y /
Metering Signals Project ‐ A&A for VIC ROADS:S
Video
Surveys
Video
Automatic traffic counter
Vid t il
Automatic traffic counter for circulating traffic
Manual turning
Video trailer
volume counts
53 of 61
Metering Signals Project ‐ A&A for VIC ROADSg g j
The roundabouts covered by the VIC ROADS project are shown in following slides.
For further information:AKÇELIK, R. (2008). An investigation of the performance of roundabouts with Ç , ( ) g pmetering signals. Paper presented at the National Roundabout Conference, Transportation Research Board, Kansas City, MO, USA.
www.sidrasolutions.com/software downloads articles.aspxwww.sidrasolutions.com/software_downloads_articles.aspx
54 of 61
Metering Signals Project ‐ A&A for VIC ROADS:FindingsFindings
Circulating Traffic Entry Lane Traffic Measured Estimated
Flow Flow Follow up Follow upFlow Rate
(veh/h)HVs
Flow Rate
(veh/h)HVs Critical
Gap (s)
Follow-up Headway
(s)
Critical Gap (s)
Follow-up Headway
(s)
Metered and controlling approaches togetherMetered and controlling approaches together
Minimum 134 0.0% 174 0.0% 2.13 1.44 2.17 1.4315th
percentile 356 1.1% 288 0.7% 2.79 2.02 2.54 1.84pe ce t e
Mean 674 4.6% 677 3.4% 3.20 2.30 3.37 2.1085th
percentile 984 8.6% 985 6.7% 3.60 2.59 3.98 2.38p
Maximum 1365 14.5% 1130 12.5% 4.31 3.25 4.83 3.11
55 of 61
Unbalanced flows and metering signals : Mickleham Rd Broadmeadows Rd AM PeakMickleham Rd ‐ Broadmeadows Rd, AM Peak
C t lli A hControlling Approach: Mickleham Rd North
Metered Approach: Mickleham Rd South
56 of 61
Boundary Road / Governor Road, PM Peak
Controlling approach:
y / ,
Controlling approach: Boundary Rd South
Metered approach: Governor Rd
57 of 61
Greensborough Bypass / Diamond Creek Rd, AM Peak
Controlling approach:
g yp / ,
g ppDiamond Creek Rd
Metered approach: Civic Dve
58 of 61
South Gippsland Hwy / Pound Rd, PM Peak
Controlling approach:
pp y / ,
Controlling approach: South Gippsland Hwy North
Metered approach: South Gippsland Hwy South
59 of 61
South Gippsland Hwy / Pound Rd, PM Peakpp y / ,
F ll i li d t t tFully signalised treatment http://vicroads.vic.gov.au/Home/RoadProjects/MelbourneRoadProjects/SouthEasternSuburbs/PoundRoadDandenongSouth.htm
60 of 61
END OF PRESENTATIONEND OF PRESENTATION
Thank you ...
© Copyright 2000‐2011 Akcelik & Associates Pty Ltd