VIKING Workshop

8 May 2001

Dr. Klaus Nökel

PTV

Planung TransportVerkehr AG

Stumpfstr. 1

D-76131 Karlsruhe

Tel. +49 721 96 51-0

Fax +49 721 96 51- 699

Internet: www.ptv.de

EXPO 2000 traffic management with VISUM-Online

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What is Visum-Online ?

basic traffic estimation / forecasting algorithms for traffic management centres

extension of proven VISUM platform

jointly developed by PTV and Siemens

fully integrated with PTV Vision and Siemens Concert

Installations Hannover (move GmbH) München (part of federally funded research project MoTIV) Antwerp, Belgium (under development) Berlin, Germany (under development) Shenzhen, China (in preparation)

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Why VISUM-online?

Numerous ITS facilities are deployed to improve traffic conditions, e.g. in Hannover:

32 VMS for dynamic route guidance on motor way 80 km of motorway with VMS speed control twice daily tidal flow one-way traffic on major highway 3 parking guidance systems (City, EXPO, P&R) direct access to signal control programs Links to

Roadworks Information System

Command & Control System of police and fire brigade

Operations control system for public transport

Call Centre for mobility services

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Why VISUM-online?

Support decisions about traffic management measures through display of current level of service (LOS) preview of LOS for 30 - 60 minutes forecast of effects on LOS of proposed traffic management

measures

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Architecture of Visum-Online

Transportation Modelling (VISUM-online)Input

Networks

A: Navigation

B: Planung

C: Prognose

relational database (Oracle)

graphical UI

OD

BC

OD

BC

InputDemand

Fij-Matrizen:

• Normalverkehr

• Veranstalt-ungsverkehr

graphical UI

Model

• Datenvervoll-ständigung

• Kurzfrist Prog.

• Tagesprognose

Output

• Verkehrslage

• Verkehrslage in 15,30,45,60 min

• Prognose nächster Tag

SubsystemInterface

External Data (Subsystems)

Network

Dynamische Daten

• Baustellen

• Richtungswechsel

OD

BC

OD

BC

SubsystemInterface

TrafficControl

LSA

Parkleitsystem

Park+Ride Info

SubsystemInterface

TrafficCounts

Schleifen

Video

Infrarot.

SubsystemInterface

Incidents

RDS-TMC

Polizei ELR

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Hannover: Available Data Sources

Traffic volume at selected detector loops (motorway, signal controlled junctions)

Speed at delected detector loops (motorway)

State of variable message signs and route guidance

Messages from RDS/TMC radio warning system

Current roadworks and incidents

Car park status (percentage filled)

Major cultural events (with impact on demand)

During EXPO 2000: advance ticketing information

Weather

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Volume

Volume

Impedance

Impedance

Demand

Demand

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Hannover: Output

Sensor fusion: GIS system allows simultaneous viewing of all traffic-related information

Level of service (LOS): interpolation of most recent measurements produces volume + speed on all network links

Short-term forecast: extrapolation of current LOS for next 30 minutes (traffic flow simulation)

What-if forecast: like short-term forecast, but with the assumed effects of a proposed traffic management measure

Medium-term forecast: LOS for the next day based on historic trend lines and current information about events, road closures etc.

Visualisation for traffic management operator and distribution of traffic information via Internet, TV, Fax, email, print media

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VISUM-online

Data Completion

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Algorithm for Data Completion (1)

Input OD matrix as initial solution volume from isolated detectors

Algorithm Path Flow Estimator (PFE) by Mike Bell, University of

Newcastle on Tyne, UK

Principle Iterated equilibrium assignment with simultaneous adjustment

of impedances

Result Estimated current OD matrix Routes

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Algorithm for Data Completion (2)

Input Routes with volumes from PFE measured volume and speed from detectors

Algorithm Propagation algorithm by PTV

Principle propagate q and v onto links in the neighborhood of detectors,

degree of confidence decreases with distance from detector

Result volume and speed on all network links reproduces inhomogenous distribution of vehicles along routes

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Propagation algorithm: initial state

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Propagation algorithm : Result

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Algorithm for Short-Term Forecast

Input Link volumes from propagation algorithm OD matrices and routes from PFE „Effects of measures“, e.g. roadworks, signal programs

Algorithm mesoscopic traffic flow simulation (Dynemo)

Principle movement of individual vehicles in accordance with

macroscopic indicators of traffic situation (density, avg. speed)

Result 30 - 60 minute forecast of volume and speed on network links travel time forecasts on fixed routes

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Short-term Forecast under scenario assumptions

30 min

Strategy A

30 min

Strategy B

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Algorithm for Day Forecast

Input static network „Effects of measures“, e.g. roadworks, signal programs hourly OD matrices (base traffic + visitor traffic)

Algorithm dynamic assignment

Principle assignment in 15 min slices, taking into account unfinished

trips from previous slices, vehicles „jump“ in 15 minute steps

Result 1 day forecast of volume and speed on network links

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Day Forecast: Result

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Architecture of Hannover System

Editor PoliceLAN

Traffic Volume, Weather, Incidents, Events

Data Flow

Actuators

Sensor FusionAnalysis

ForecastsCore

Database User Interfaces toSubsystems

ParkingGuidance

Variable Message Signs

Traffic

Management

LAN

Multivision Display Wall

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Display of detector readings

Visum-Online

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Case 2: Link is part of subordinate network, therefore only present in navigation network

Case 1: Link represents future network, therefore only present in planning network

Case 3: Main road, therefore present in all 3 layers, but with varying number of intermediate nodes

Navigationsnetz

Planungsnetz

Prognosenetz

Networks differ in level of detail:Forecast network:~3800 links~220 zones

Planning network:~12000 links~650 zones

Hierarchy of Networks

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Traffic flow effects of incidents

Incidents and roadworks decrease the capacity of the infrastructure and potentially lead to congestion.

This effect is uniformly modelled by decreasing qmax (capacity) and v0 (free flow speed)

Subsystems do not attach resulting qmax and v0 to roadworks and incident messages, therefore traffic engineer in managament centre appends this information

Generating complete alternate network versions for temporary effects is too much overhead and complicates modelling simultaneous measures

Solution: Effects are stored as „infrastructure effect lists“ (German: Netzwirkungslisten, NWL). Each NWL contains a list of tuples(Network element, attribute, new value, validity period)

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create new NWL root node

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set name and default validity period

commit

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select link

add to NWL root

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appears in NWL tree view

set validity period

commit

set effect

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Hannover system: further functionality

demand editor (visitor traffic)

editor for scenario definition (incl. simulation)

difference view for comparing two simulation results

aggregation of detail data to historic trendlines

display of operating status, control of subsystem converters

user administration, user rights

...

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Hannover system: initial experience

Phased deployment CeBIT 1999: basic visualisation of traffic counts Autumn 1999: data completion and short-term forecast CeBIT 2000: day forecast

Quality of results Data completion and day forecast good, but detector coverage

still sparse in many areas Short-term forecast currently only on motorways and freeways,

will be extended as more detectors come on-stream

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Quality of Results

Measured and predicted (in absence of detector) traffic volumes are almost identical (Flow_real vs. Vol_PFE)

Predicted speed has correct profile, but consistently too low (-> v0 needs to be recalibrated)

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Volume [veh/h] Speed [km/h]

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VISUM-online: a traffic manager‘s dream

for more information: klaus.noekel@ptv.de