Missing your forecast

| 2 Comments

From today's Sydney Morning Herald: Cross City Tunnel receivers put tollroad on sale block . The tollroad tunnel went under (so to speak) in part because they missed their forecast, getting 30000 travelers per day instead of 90000.
Oops.

Another article on this in Toll Roads News The firm responsible for the forecast was Hyder Consulting who remarkably still claim credit for the project on their website.
Oops.

Forecasting traffic is not easy, but there are established methods that should get freeway demand estimates within 20-30% or better (i.e. one lane) of actual values (not 300% off) and one is not convinced these guys used them. In fact, even with no tolls, traffic was still only 60% of the predicted flow.

Unfortunately, there is really no liability for poor forecasts, at least not for the forecasters.

Of course this points out the advantages to private sector assuming the risk, the public is not on the hook for a bailout. It also argues for higher returns to compensate for the risk, otherwise projects won't get built.

2 Comments

We note your comments indicating that Hyder Consulting conducted traffic modelling on Cross City Tunnel on behalf of the Cross City Motorway consortium ('CCM').

By way of clarification, Hyder Consulting was engaged by CCM to prepare a traffic study co-ordinating the outputs from CCM's other consultants and to assist in communicating the contents of the study.

CCM engaged another organisation to undertake traffic modelling that formed the basis for traffic forecasts in that study. CCM is best placed to provide information regarding the model utilised.

Please contact cindy.lee@hyderconsulting.com for further information.

From Hyder's website below ... it looks like as lead consulant and project manager they should be takingsome responsibility for the forecasts.

From their site:
http://www.hyderconsulting.com/proj_datasheets/proj_1647_data1_FB24598B-410E-4F5D-A843-2.pdf

Date July – December 2002
Client Cross City Motorway
Consortium (CCM)
Responsibilities
Lead consultant and project manager for
Netanal modelling to produce traffic forecasts
for revenue modelling
A total of approximately 580,000 vehicles
access the Sydney CBD daily, over half of
which is through traffic. Sydney’s existing
transport network provides good connections
for traffic travelling north/south and
north/west, but poor connections on
east/north and east/west routes. As a result
traffic flow through the CBD is highly
inefficient and time consuming.
Additional problems such as bus lanes along
principal travel routes, on-street parking,
access to driveways and alleyways,
pedestrian “scramble? phases at signalised
intersections and pedestrian operated
crossings and general CBD activity
throughout Sydney’s complex system of one-
way streets has resulted in the RTA
identifying the need for a major new east-
west road connection across the CBD with
connections to major access routes. Cross
City Tunnel (CCT) serves this need and
relieves traffic congestion and infiltration into
local streets through the CBD.
The CCM Consortium appointed Hyder
Consulting to lead a team of consultants –
the Patronage Team – to undertake a
detailed analysis of the patronage forecasts
and implications for potential traffic using
CCT. The identified benefits of CCT
included:

Diversion into the tunnel of most traffic
currently using the east/west network


Improved operational and functional
capacity at key intersections in the CBD
to lower congestion and improve travel
efficiency

Travel time reductions of approximately
20 minutes from east to west Sydney

Improved bus travel times and less
delays for pedestrians at traffic signals

Reduced traffic noise and improved air
quality.

David Levinson

Network Reliability in Practice

Evolving Transportation Networks

Place and Plexus

The Transportation Experience

Access to Destinations

Assessing the Benefits and Costs of Intelligent Transportation Systems

Financing Transportation Networks

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This page contains a single entry by David Levinson published on April 2, 2007 2:07 AM.

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