rudimentary transport science: ceiling capacities for urban roads
DESCRIPTION
Submission to the Joint Select Committee on the Cross City Tunnel 1 February 2006 Michelle Zeibots, CMILT Riga Consulting. Presentation overview. Rudimentary transport science: ceiling capacities for urban roads. Terms of reference and CCT traffic volume estimates. - PowerPoint PPT PresentationTRANSCRIPT
Submission to theJoint Select Committee
on the Cross City Tunnel
1 February 2006
Michelle Zeibots, CMILT
Riga Consulting
2. Rudimentary transport science: ceiling capacities for urban roads
1. Terms of reference and CCT traffic volume estimates
3. CCT traffic estimates areabove the ceiling capacity
4. Reform of processes for technicalscrutiny of projects
Presentation overview
Current Cross City Tunnel traffic volumesare well below forecasts
Consortium forecasts 98,000 AADT for 2006
EIS forecasts 52,700 (tunnel) AADT69,600 (SJY Cres) AADT for 2006
Actual volumes 25,000 - 35,000 AADT for 2006
Public perception of the project:
1. Not value for money
2. Private sector involvement means: • manipulation of surface roads • reduced public transport services to increase road traffic and tollway revenue
3. Tollway building is about private sector business opportunities not meeting community transport needs
Consortium forecast 98,000 AADT for 2006
The Consortium’s forecast is above the ceiling capacity of the road.
It is unlikely the facility will ever carry 98,000 AADT.
Sydney Harbour Bridge and Tunnel
An
nu
al
Av
era
ge
Da
ily
Tra
ffic
(A
AD
T)
Sydney HarbourBridge + Tunnel
1971 134,7401973 139,4301975 145,3501976 150,8401979 159,2701981 166,4301983 172,5701985 178,1701986 180,6501987 180,3661988 184,2301989 182,0241990 180,5001991 181,8781992 165,1901993 138,3981994 1445101995 149,391
Sydney Harbour Tunnel(opens August 1992)
50,000
70,000
90,000
110,000
130,000
150,000
170,000
190,000
210,000
230,000
250,000
Sydney Harbour Bridge
Sydney Harbour Tunnel
1971 1975 1979 1983 1987 1991 1995 1999
ceiling capacity ramp-up
ceiling capacity for SHB is 180,000
mlc x lanes x ef = ceiling capacity
1. mlc is max. lane capacity / hour
2. lanes is number of road lanes
3. ef is the expansion factor
How is the ceiling capacity calculated?
1. Maximum lane capacity
Source: Austroads, 1999, Guide to traffic engineering: roadway capacity. Vol.2, Austroads Publication No.AP–11.2/88, Sydney, p.20.
maximum lane capacity for SHB is 2,000
2. Lane numbers
8 lanes operating under tidal flow conditions
number of operating lanes on SHB is 9
3. Expansion factor
0
2,000
4,000
6,000
8,000
10,000
12,000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
1985
1989
1996Ho
url
y T
raff
ic V
olu
mes
60,000
65,000
70,000
75,000
80,000
85,000
90,000
95,000
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51
Ave
rag
e W
eekl
y D
aily
Tra
ffic
expansion factor for SHB is 10
What is the ceiling capacity of the Sydney Harbour Bridge?
1. Maximum lane capacity = 2,000
2. Number of lanes = 9
3. Expansion factor = 10
2,000 x 9 x 10 = 180,000
1971 134,7401973 139,4301975 145,3501976 150,8401979 159,2701981 166,4301983 172,5701985 178,1701986 180,6501987 180,3661988 184,2301989 182,0241990 180,5001991 181,8781992 165,1901993 138,3981994 1445101995 149,391
Cross City Tunnel configuration
two lanes in each direction
What is the ceiling capacity of theCross City Tunnel?
1. Maximum lane capacity is 2,000
2. Number of lanes is 4
3. Expansion factor is 10
2,000 x 4 x 10 = 80,000
Consortium estimate of 98,000 AADTConsortium estimate of 98,000 AADTis 18,000 above the ceiling capacityis 18,000 above the ceiling capacity HOW?
HOW?
EIS forecast 52,700 (tunnel) AADT 69,600 (SJY Cres) AADTfor 2006
This EIS figures are below the ceiling capacitybut higher than historical volumes forWilliam Street traffic with destinations not in the CBD.
Linear ramp-up pattern proposed by the RTA’sConsultants after opening, is not indicative ofhistorical data for ramp-up periods in Sydney.
2.0012.001William StreetWilliam StreetKings Cross TunnelKings Cross Tunnel
2.0012.001William StreetWilliam StreetKings Cross TunnelKings Cross Tunnel
30,000
35,000
40,000
45,000
50,000
55,000
60,000
1985 1987 1989 1991 1993 1996 1999 2002
An
nu
al A
vera
ge
Da
ily T
raff
ic (
AA
DT
)
ceiling capacity
1985 44,899
1987 47,942
1989 50,939
1991 51,491
1993 52,619
1996 55,110
1999 53,085
2002 52,935
2.0012.001William StreetWilliam StreetKings Cross TunnelKings Cross Tunnel
choke point with ceiling capacity of 52 – 53,000
Source: Masson, Wilson, Twiney. 2005, Review of post opening traffic demand for Cross City Tunnel. Roads & Traffic Authority of NSW, Sydney, p.4.
RTA traffic projections after ramp-up period
SUTHERLAND
CAMPBELLTOWN
HURSTVILLE
LIVERPOOL
SYDNEY
CHATSWOOD
HORNSBY
Lidcomb
Parramatta
PenrithBlacktown
Richmond
M4
M4 Motorway & Great Western Highway: Average Weekly Traffic
M4 Motorway & Great Western Highway : Daily Traffic Volumes
What should be done?
Under Terms of Reference 1 (e) & (f)
1. A mechanism (process or organisation)be established to check technical acumen of traffic forecasts and othercritical points of analysis
2. The mechanism should function independently of the proponent agency and commercial consortium
Suggested models
1. SACTRA — Standing Advisory Committee on Trunk Route Assessmenta group of experts that report directly to the UK Minister for Transport
2. NATA 5 — assessment process that replaced the EIS processIncludes Multi-model and Economic Impact statements