Enhanced analytical decision support tools

The Scheme levelFinal workshop of the DISTILLATE programme

Great Minster House, LondonTuesday 22nd January 2008

Dr Simon ShepherdITS, University of Leeds

ObjectivesObjectives/Indicators

(7)

Assess problems (8)

Possible instruments (9)

Predict impacts (12)

Compare solutions (13)

Implement (15)

Evaluate performance (15)

Monitor (15)

Barriers (10)

Possible strategies (11)

Optimisation (14)

Appraisal (13)

Scenarios (11)

• To enhance existing predictive models to represent a wider range of policy instruments

• To improve the ability of users to apply models

Suggested Themes

1. Demand restraint measures 2. Public transport improvements3. Land use measures4. Soft measures (attitudinal)5. Slow modes and small scheme

impacts6. Data issues7. Model use

Demand restraint modelling

• Cordon location –short cut approach

• Area based charging

• Parking choice model

Cordon Location Problem

Top 15 links – high marginal cost tolls

A short cut approach• Aim to develop a method between

judgement and GA based approach• Use fact that Top 15 MC tolls gave high

proportion of first best benefits• Charge a high cost trip somewhere – not

necessarily on the high cost links• Use SLA to design where best to place

cordon and catch the high cost flows

Display SLA using bandwidths

Summary cordon location

• Proven for networks of Cambridge, York, Leeds and Edinburgh

• Adapted for simulation networks of Shrewsbury and Cambridge

• Approach included in DfT webtag advice

• Now being used on Nottingham network

Area based charging

• Adapt models to charge for trips within an area rather than per crossing of a cordon

• Allow exemptions or discounts for residents

• Implemented in SATURN

• Tested on a Cambridge network

Example for a given cordon

Cambridge Inner Cordon: Cordon Charging vs Area Charging

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Area based charging benefit surface

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Benefits, £

Cordon Fee, Pence

Area Fee, Pence

Surface of Benefits12000-13000

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Parking model - Aims

• Develop a simple parking location choice model with the demand spread over multiple time periods

• Integrate within assignment stage of the transport modelling process

• Develop a modelling framework that can be used to test parking demand management policies

• Illustrate the method with practically available data for a realistic network of Leeds

Implemented for Leeds SATURN model

Car park 1

Car park 2

Parking summary

• Car park choice for multiple user classes and across time periods has been incorporated within an equilibrium assignment approach (matching Lam et al)

• Impact of car park pricing structures/capacity can be modelled with the approach

• Further possible extensions – departure time choice, elastic demand, etc.

Improved Public transport modelling

1. DRACULA – Bus reliability

2. STM Partial modelling of Trip chaining (extended park and ride)

DRACULA – Bus reliability

• Incorporates interactions between bus operation, passenger arrivals, boarding times and private traffic.

• Simulation helps understand impacts on reliability and tested alternatives to increase reliability

• York case study

The DRACULA model of Route 4

• The bus route in red

• DRACULA model: – 138

junctions (39 signalised)

– 260 links– 21 bus

stops– 2 bus lanes

Results of model validation

• Ten simulation runs, over a period of 1.5 hours, 12 services each run• Modelled average journey times correspond well with observation• Model correctly predicting journey time delays at the key sections en-route

Travel time between bus-stops

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Modelled Vs Observed Average Link Travel times in different

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Modelled Vs Observed Average Link Travel times in different

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Summary of results• Headway variation and number of passengers boarding

interrelated:

• Unreliability increases with congestion and passenger demand

• Passenger demand has more serious impact on headway variability than on total journey time

• Extension of bus-lane itself does not improve reliability, but combined with signal gating strategy will bring benefit

• Reduced boarding time (advanced ticketing system) brings in most significant improvements

STM – Park and Ride• Treats trip chaining in terms of park and ride at

Glasgow underground stations (Subway system). The entire Subway system can be modelled.

• Uses model of capacity constraint including ‘overflow’ model to transfer excess demand at car parks.

• Used to investigate interaction between direct travel to Glasgow centre and by Subway park and ride in context of strategic model.

Subway choice sets

• Additional program used to generate viable Subways for choice for each OD movement.

• Based on routes for direct travel

• Currently up to 5 Subways possible ( a middle possibility and 2 side alternatives)

Subway catchment zones

Subway catchment area (blue) and mode shares for this

Run I (50% increase in jobs) – impact on Subway system

% mode share increases for all the catchment zones – Subway increases by about 16%

QUESTIONS?

Contact : Dr Simon Shepherd

Institute for Transport Studies

University of Leeds

S.P.Shepherd@its.leeds.ac.uk

Tel : 0113 343 6616