Preliminary Report SUTRA : Sustainable Urban Transportation for the City of Tomorrow WP 03: Multi-modal Transportation Modelling D03.1 Implementation Report Second Draft Karlsruhe, January 2002 PTV Planung Transport Verkehr AG Preliminary Report SUTRA : Sustainable Urban Transportation for the City of Tomorrow WP 03: Multi-modal Transportation Modelling D03.1 Implementation Report Second Draft Prepared for: Commission of the European Communities Research Directorate-General Prepared by: PTV Planung Transport Verkehr AG Author: Josef Janko Karlsruhe, January 2002 PTV Planung Transport Verkehr AG Error! No text of specified style in document. Executive Summary Transportation problems are among the most pressing strategic development problems in many cities, often a major constraint for long-term urban development in general. In SUTRA these problems are addressed with a consistent and comprehensive approach and planning methodology that helps to design strategies for sustainable cities. This includes an integration of socio-economic, environmental and technological concepts to improve forecasting, assessment and strategic policy level decision support. It uses traffic equilibrium modelling to evaluate alternative transportation policies, including multi-modal systems and their relations to land use, technological development, socio-economic development, and spatial and structural urban development in general. To evaluate scenarios for sustainable urban transportation an existing transport model software will be enabled to deal with multi-modal aspects like Park+Ride traffic. Special attention will be given to the prioritisation of high-occupancy vehicles and road user charging, but any other scheme of sustainable transportation may be considered, if it is of relevance for one of the demonstration sites in the project. As a number of decision support indicators will be estimated from dedicated models (for emissions, air quality, public health, economic and energy system analysis) relying on the output of the transport model, it has to be guaranteed, that their relevant input data are made available. Specifications and interface requirements have been defined between the developers of the models. Using the modelling software local transport models will be developed for the seven participating cities and applied to common and individual scenarios to reveal the influences and the consequences of transport schemes to socio-economic and environmental aspects of urban living conditions. PTV AG 07/00 page 3/25 Error! No text of specified style in document. Contents Executive Summary ................................................................................. 3 Contents.................................................................................................... 4 1 2 3 4 Introduction ..................................................................................... 6 1.1 Objectives ................................................................................ 6 1.2 Description of work ................................................................... 6 1.3 Deliverables ............................................................................. 7 1.4 Milestones and expected results .............................................. 7 Transport Model: Background and Methods ................................. 8 2.1 Structure of Transport Models .................................................. 8 2.2 Modelling of Traffic Demand ................................................... 10 2.3 Modelling of Traffic Impacts.................................................... 10 Modelling of Sustainable Transport Modes ................................. 12 3.1 Park+Ride .............................................................................. 12 3.2 High-Occupancy Vehicles ...................................................... 15 3.3 Road User Charging............................................................... 16 3.4 Other Strategies of Sustainable Urban Transport ................... 17 Model Interface .............................................................................. 18 4.1 Input Data .............................................................................. 19 4.1.1 Demand data .......................................................................... 19 4.1.2 Supply data............................................................................. 19 4.2 Output data ............................................................................ 20 PTV AG 07/00 page 4/25 Error! No text of specified style in document. 4.2.1 Emission model interface ........................................................ 21 4.2.2 Energy model interface ........................................................... 21 4.2.3 Public health model interface .................................................. 22 4.2.4 Environmental impacts model interface .................................. 22 4.2.5 Economy impacts model interface .......................................... 22 4.3 Data Exchange....................................................................... 22 5 Conclusions and Outlook ............................................................. 23 6 References ..................................................................................... 25 PTV AG 07/00 page 5/25 Error! No text of specified style in document. 1 Introduction 1.1 Objectives Workpackage 3 of SUTRA deals with multi-modal transportation modelling. The objectives are: To adapt an existing traffic equilibrium simulation model for multi-modal traffic including private and public mass transport systems, high-occupancy vehicles, and other trip-reducing strategies, based on the requirements and constraints analysis undertaken in workpackage 1. To develop the interfaces of the traffic simulation model to the related analytical components: emission model and near-field street canyon modelling (workpackage 4), air quality modelling (workpackage 5), general environmental impact assessment (workpackage 6), energy analysis (workpackage 7), economic assessment (workpackage 8), and public health impact assessment (workpackage 9). 1.2 Description of work The workpackage will enable the modelling of inter-modal trip chains, park+ride traffic (including optimal choice of locations for mode interchanges), road user charging, and prioritisation of high-occupancy vehicles (HOV), in terms of their potential to lower the economic and environmental costs of mobility. Workpackage 3 will build on a widely used transport planning software that uses a modeintegrated network and demand model. For the full range of policy options the model will be extended with methods for inter-modal routing, Park+Ride, and HOV prioritisation. This will include public transport features where necessary. Interfaces will help transfer the results of the transport model to the economic and environmental models of the other project partners. This kind of model chaining has already been successfully demonstrated in an ESPRIT project where this model also played the role of the transport model in a transportation/environment context. While the workpackage is designed for an initial 12 months period, it is expected that modifications of the model will be an ongoing, though low-level activity throughout the whole duration of the project based on feedback provided by the city partners. PTV AG 07/00 page 6/25 Error! No text of specified style in document. 1.3 Deliverables The work undertaken in WP03 will be documented in three deliverables: D03.1 Multi-modal transportation modelling (Implementation Report) D03.2 Transportation Model prototype D03.3 Transportation model: User Manual and example test data sets 1.4 Milestones and expected results This workpackage will contribute to Milestone 2, which is due at PM 12. It is a description of the availability of the first model versions for the individual application sites. As final result of workpackage 3 it is expected, that the methods developed in SUTRA are available as normal features in the transport modelling software package VISUM. PTV AG 07/00 page 7/25 Error! No text of specified style in document. 2 Transport Model: Background and Methods 2.1 Structure of Transport Models Transport models consist in general of two main components (Figure 2.1): the data base as numerical input the software with the methods and algorithms of the transport planning process Transport Model Data base Structural data Behavioural data Network data Figure 2.1 : Software Demand model Assignment model Transport Model Components The design and application of a transport model is determined by the interdependency between algorithms and methods on one hand and the availability of data on the other hand. The application of the transport planning algorithms is generally structured into four separate processes: Trip generation Trip distribution Modal split Trip assignment Figure 2.2 shows the interactions between these four elements. The first three elements, trip generation, trip distribution, and model split define the demand model. The fourth element is the supply side defined by assignment of trips to the public transport and highway networks. A key feature of the model is that demand is inextricably linked to supply in an iterative process in which the performance of the transport networks resulting from the „loading“ of demand in the assignments is cycled back into further runs of modal choice, distribution and possibly generation. PTV AG 07/00 page 8/25 Error! No text of specified style in document. Demand Model Structural and Behavioural data Population, behavioural homogenous person groups Activity chains Structural data, attractiveness of zones Trip Generation (Activity Model) Activity related impedance matrices Trip Distribution (Trip Chains) Service Quality Mode Choice (LOGIT Model) Mode attribute matrices Matrix Mode 1 e.g. passenger cars Trip costs PrT Trip costs PuT Matrix Mode 2 e.g. road freight transport Matrix Mode n e.g. public transport Traffic Assignment Private Transport Traffic Assignment Public Transport Network description Assignment Model Figure 2.2 : PTV AG 07/00 Transport Model Interactions page 9/25 Error! No text of specified style in document. 2.2 Modelling of Traffic Demand There are two different categories of demand models, analytical and synthetic models. As their main difference can be noted, that analytical models describe the trip generation, while synthetic models try to explain demand: Analytical models use structural data like numbers of inhabitants, employees, workplaces, schoolplaces and generation rates to estimate origins and destinations of trips in zones for a particular time period. Synthetic models use beside structural data also behavioural data to model activity chains of so-called behaviourally homogenous person groups and to derive from these the origins and destinations of trips. As in synthetic models trip chains for a whole day are generated the trip distribution and the mode choice have to be linked to the trip generation [2]. 2.3 Modelling of Traffic Impacts Transport systems have impacts in different forms on system operators, on individual users, and on the general public. The road network is usually operated by the state, federal states or municipalities and increasingly by private investors. These "operators" of the road network have to decide on investments for the construction and maintenance of road infrastructure. The Public transport operators are transport companies or transport associations. To offer a public transport service, Public transport operators develop line networks and timetables from which the user can then choose connections. Users of infrastructure for private transport are mostly car drivers and their passengers, but also non-motorised travellers such as cyclists and pedestrians. Users of public transport are public transport passengers. Important indicators for evaluating transport systems are journey times and travelling expenses. To evaluate a public transport system, additional indicators such as availability and frequency of service, number and quality of transfers, and seat availability have to be considered. Beside these direct individual aspects also impacts of travel demand on the general public have to be considered: Pollution. Combustion engines and power plants produce emissions with consequences to health and the environment. Energy consumption. Transport consumes energy Costs of accidents. Traffic accidents cause injuries and fatal casualties with damage to the economy. PTV AG 07/00 page 10/25 Error! No text of specified style in document. Impacts of traffic can be derived from the output of the assignment model. The principles and methods of traffic assignment have been developed over a long time [3, 5]. State of the art are different variations of equilibrium methods. This means, that the chosen routes for all the travels in a transport network meet the minimum of an objective function, which cannot be improved by shifting trips between routes. Examples for objective functions can be the total amount of time spent in the network or minimum journey times for all the travels in the network. Assignment methods allow basically estimates of transport related indicators like volumes or journey times on roads. The above mentioned impacts go beyond the scope of transport models and therefore have to be evaluated with separate models. PTV AG 07/00 page 11/25 Error! No text of specified style in document. 3 Modelling of Sustainable Transport Modes In this project work is focussed on sustainable transport modes. This particularly deals with all forms of public transport and means of restricting private transport. Special interest is directed to Modelling of Park+Ride Modelling of facilities for high-occupancy vehicles Modelling of road user charging schemes The following sections describe the way, in which the transport model can be enabled to evaluate the effects of such measures. 3.1 Park+Ride Figure 3.1 : Example for a P+R system Park+Ride describes travels in conurbations from the outskirts to the centre, which are undertaken partly by private and partly by public transport. The first part in the PTV AG 07/00 page 12/25 Error! No text of specified style in document. less dense outer areas with usually less density of public transport is made by car. The car is parked at a station or a stop of a bus or rail service, from where the second part of the journey is continued to the destination in the centre of the city. In this way one tries to combine the advantages and to avoid the disadvantages of both transport systems. Figure 3.1 shows an example for Park+Ride in an urban area with the private transport part of travel in red and dedicated P+R services in blue. To the potential clients four facilities are available, which are linked to the city centre with bus lines. Modelling of Park+Ride trips requires a sequence of steps. The approach can be outlined as follows: Definition of P+R sites Determination of P+R demand Split of P+R demand into private transport and public transport legs Assignment of P+R trips as parts of the demand segments for private and public transport The general modelling assumption is, that P+R trips are genuine private transport travels, which can be shifted to public transport as a consequence of an improved service. In the network model a P+R site has to be represented as a zone and a link. Zones are necessary as elements, where travels within a transport system start and end. A change between private and public transport therefore requires a zone. In the P+R links of the model two properties have to included, the capacity of the P+R facility and the costs for using P+R. The P+R links, like all the other links in the network model, have a limited capacity, which is here defined by the number of parking places and number of changes during a day. This allows to include different trip purposes with different durations of stay (commuters, shoppers). Also costs for parking and bus fares can be defined in the impedance of these P+R links. In a first step the impedances for the public transport legs of P+R trips have to be defined with the Assignment model. This requires a selection of potential destination zones of P+R trips by the modeller. Parameters for this determination would be the destinations and journey times of the available public transport services for the existing or potential P+R sites. The destination zones have to be connected to the P+R sites. A first assignment run is made in which the numbers of clients using the P+R sites are estimated for the whole modelling area in competition to private transport on the whole journey. Figure 3.2 depicts the transport model representation of a P+R facility with the real public transport service and the modelled connections to some of the zones in the city centre. PTV AG 07/00 page 13/25 Error! No text of specified style in document. Figure 3.2 : Transport model representation of a P+R facility A second assignment however is necessary to assign these travellers to the public transport leg and to provide their correct return trip. As it is not mandatory in the trip assignment that for both directions of a journey the same connection of a zone is used, it has to be guaranteed, that P+R customers start their private transport return trip from the same place where they left their car. Therefore the P+R return trips have to be removed from the original demand matrix for the private transport segment and have to be entered as new relations between the P+R site and their final destination. In this same model run the P+R clients have to be assigned to the public transport services between the P+R facilities and the city centre. In detail this requires the following steps: 1. Preparation of the network model Definition of the the P+R sites as links and zones Definition of the public transport services for these sites. Estimation of potential P+R destinations through determination of isochrones for the relevant public transport services Definiton of the relevant connectors between the P+R sites and the destinations PTV AG 07/00 page 14/25 Error! No text of specified style in document. 2. First assignment to estimate the demand matrix for the P+R clients; validation against reference data. 3. Modification of travel demand Select link analyses for the P+R site links generate the matrices of P+R trips from the origins to the final destinations in the city centre (original P+R trips). These trips are removed from the private transport matrix. The P+R facilities are defined as destinations of the original P+R trips, and these trips are added to the private transport demand. The P+R facilities are defined as origins of the original P+R trips, and these trips are added to the public transport demand. The return trips have to be treated in the same way. 4. Second assignment with modified demand for the public and private transport systems. The whole procedure has to be calibrated in a possible iterative process, if the shift from private to public transport is of a magnitude which has influence on the mode choice decision: if the reduction of private traffic is so big, that congestion is relieved, car usage might be encouraged again. 3.2 High-Occupancy Vehicles The term „High-occupancy vehicle“ (HOV) can include buses, vanpools, carpools, and other authorised vehicles. The focus of projects to promote HOV lies on carpools; most facilities use a two person (2+) per vehicle carpool definition, but some require three person (3+) carpools. Incentives for participating in a carpool can be Availability of dedicated HOV lanes Parking spaces at convenient locations only for HOV Exemption from road user charging for HOV In the transport model high-occupancy vehicles also are regarded as carpools. They have to be defined as a transport system of their own. Dedicated HOV links can be prepared in the network model which are blocked for other vehicles. Where no particular HOV links are available, these vehicles join the other vehicles in common links. Demand for carpooling has to be determined in a demand model. These trips may be defined in two categories: PTV AG 07/00 page 15/25 Error! No text of specified style in document. The whole trip is done in a carpool. An estimated share of demand for private travel has to be split from the private transport matrix and moved to an HOV matrix. Carpool members start their trips separately, meet at an agreed place (e.g. beginning of a HOV lane), and travel then together. In this case the treatment of HOV demand is similar to the processing of P+R trips. The demand has to be removed from the private transport matrices first and then added back again for the private transport legs of the trips, while the HOV legs are part of the HOV demand. 3.3 Road User Charging Road user charging has been applied on motorways in a number of countries for a long time. In cities or dense urban areas however road user charging has been not been applied widely. Prominent exception is the city of Singapore, where a charging scheme is effective now since 30 years. Few cities in Europe have installed similar projects as case studies during the last years. Genoa, one of the SUTRA city partners, prepares an area wide scheme for its centre. Conventional methods to model road user charges apply a constant value of time which can be included in a generalised cost function of a monocriterion assignment method [4]. TRIBUT is a bicriterion traffic assignment method which equally considers travel time and cost. The trip choice between different paths is modeled by defining the value of time as a random variable with a distribution of the log-normal type, thus considering that each trip has a specific willingness to pay toll for travel time reduction. This approach offers a significantly better price elasticity than monocriterion methods. Its most prominent features are randomly distributed values of time, the principles of path search and path choice. Furthermore it presents different aspects of the application in practice, in particular the definition of different demand classes, the modelling of linear or non-linear pricing schemes and the value of time estimation. A detailed description of the TRIBUT method can be found in [1]. Within the transport model a wide range of scenarios can be tested: Charging for entering areas (city centre) Charging for use of single parts of the road network (bridges, motorways) Charging of particular users (goods vehicles, passenger cars with only one person in it) Charging at peak hours Combinations of all these PTV AG 07/00 page 16/25 Error! No text of specified style in document. 3.4 Other Strategies of Sustainable Urban Transport Sustainable urban transport is not restricted to the application of policies described above. Other strategies to reduce negative consequences of motorised private transport can be modelled without any major limitations, e.g. Modifications of the road network including area wide traffic calming as well as removal of local bottlenecks Traffic management schemes (including transport telematics) Increased use of environmentally friendly transport modes Introduction of new public transport systems Reductions of emissions and energy consumption caused by technological development Travel demand reductions due to changes in land use It must be stated however, that the quality of the results of the transport model depends to a great extent on the precision of the input data, in particular the data for travel demand. PTV AG 07/00 page 17/25 Error! No text of specified style in document. 4 Model Interface In the SUTRA context the transport model is the first in the chain of models to evaluate city development scenarios. Figure 4.1 gives an overview of the data exchange between the transport model and the other subsequent models. Public Health Environment Volumes, link lengths, journey times Emission Volumes, speeds, trip lengths, number of cold starts, ratio hot/ cold driving Volumes, trip lengths, journey times Volumes, trip lengths, journey times Transport Model Demand: OD-matrices for different segments Economy Volumes, speeds Energy Supply: networks for different modes City Infrastructure Figure 4.1 : SUTRA Transport Model Interfaces Expanding the point of view beyond SUTRA, a transport model also needs an input data base for demand and supply modelling. It is assumed, that these data are available from external sources and can be imported into the transport model. The transport model software applied in SUTRA, VISUM, is part of a comprehensive software package for traffic planning and traffic engineering. It is running under a Windows environment. PTV AG 07/00 page 18/25 Error! No text of specified style in document. 4.1 Input Data The transportation model determines the impacts of existing or planned transport supply which can encompass both the private transport network and the public transport network. The transport planner is supported in developing a supply design, in analysing the supply, and in evaluating network variants. A transport model in VISUM consists of supply data and demand data. The following sections give an overview of these data. A complete description can be found in the software documentation. 4.1.1 Demand data Transport demand data have to be generated separately from the traffic assignment model. The most important method is the application of a dedicated traffic demand model software to produce the required data. Demand data must be made available in a matrix form describing travel demand, i.e. the number of trips for every relation between zones in the network model for the considered time period, e.g. a complete day or a peak hour for all considered demand segments In general, demand segments represent the different modes of transport, e.g. passenger cars, bus, light or heavy rail. 4.1.2 Supply data Transport supply data are represented in a network model. The integrated network model distinguishes between "private transport" and "public transport" modes. By combining different means of transportation and modes, the planner can define different transport systems. Basically the network model includes the following network objects which can be modified interactively: Transport systems, modes, demand segments Nodes: junctions with name, coordinates, type, and a public-transport-stopflag. Zones: name, type, centroid and boundary coordinates Global Zones: name, type, centroid and boundary coordinates Assignment of zones to global zones Link types: principal capacities and speeds, permission of transport systems PTV AG 07/00 page 19/25 Error! No text of specified style in document. Links: nodes at the beginning and the end, capacities and speeds, permission of transport systems, one-way-flag Major flows to reflect priority rules at junctions Connectors between zones and nodes: type, length, journey time, permitted modes Turning standards:node type, turning relation, initial waiting time, capacity Turning relations: permitted transport systems, initial turning penalty, capacity. Public transport operators Public transport vehicle types: name, code, transport system, number of seats, total capacity, number of vehicles, costs/km, costs/hr Lines: line name, variant, direction Sublines: line name, variant, direction, transport system, operator Lineroutes: line name, variant, direction, node, boarding and exiting flags, arrival and departure times Timetables: line name, variant, direction, first departure, headway, last departure, vehicle type Census points in links for evaluation of traffic counts Additional cost parameters for public transport links, stops, and operators user-defined areas (representing e.g. administrative units), for which indicators can be determined. Only a small part of these data is necessary to generate a functional network model which is able to produce results: transport systems, nodes, zones, links, connectors. Additional data help to manage the work efficiently and to achieve more precise results. Data can be retrieved from different sources and entered in different ways. The principal method is the input of data through the GUI of VISUM. For very large networks however it is easier to import the links and nodes from GIS databases. Also public transport data may be imported from external databases of the operators. Other objects like connectors can be generated algorithmically. 4.2 Output data The basic output of assignment models is produced in the form of maps with referenced indicators, e.g. link volumes, local speeds or chosen routes. In SUTRA this however is a task of only minor importance. As a number of other models rely on the output of the transport model it has to be ensured, that the necessary data are available with the required precision. PTV AG 07/00 page 20/25 Error! No text of specified style in document. 4.2.1 Emission model interface Estimations of emission productions are carried out in the framework of this project with TREM (Transport Emission Model for Line Sources). A description of this model can be found in Deliverable D04.1 [6]. It requires as input from the transport model the numbers of vehicles in each link of the network, and the information, whether these vehicles are driven under hot or cold engine conditions. These conditions are defined as so-called cold distances individually for different pollutants and vehicle categories. An interface has been developed, which outputs the required data in a table format to an Excel spreadsheet. An example with three vehicle categories and five pollutants is given below. Percentage of Cold Percentage of Cold Engine Petrol Vehicles Engine Diesel Vehicles for for LinkNr 25 109 110 114 115 116 Flow CO2 CO HC NOx FC CO2 CO 4891 43 33 14 33 30 4806 90 90 90 90 90 6726 90 90 57 90 90 HC NOx FC Percentage of Cold Engine Diesel Cat Vehicles for CO2 CO HC NOx FC 40 90 90 90 90 25 50 90 90 90 9069 56 47 11 47 45 10239 59 47 36 47 50 2683 43 11 7 11 10 10239 76 49 37 49 50 2683 43 9 7 9 10 8526 67 49 30 49 50 8876 87 60 50 60 60 5 5 35 50 10 90 8897 86 59 49 59 60 10 10 30 40 10 90 7929 66 50 34 50 50 9 10 5 5 15 20 50 10 10 5 5 15 20 60 40 10 10 60 40 70 5 70 Treatment of additional vehicle categories and pollutants is possible. 4.2.2 Energy model interface In the MARKAL-LITE specification as input is required the total distance covered by the vehicles of the different transport systems over the period of one year. The transport model produces link volumes as constant values over the given simulation period. The link volumes can be disaggregated into the different demand segments. The required data can be calculated by first summing up the PTV AG 07/00 page 21/25 Error! No text of specified style in document. figures for the whole network and then expanding them to the desired time period. These expansion factors have to be provided by the city partners. 4.2.3 Public health model interface No written specification is given for the public health model input data requirements. It is assumed that the required data can be derived from the parameters link volumes, link lengths, and journey times. 4.2.4 Environmental impacts model interface No specification is available for the environmental impacts model input data requirements. It is assumed that the required data (if any) can be derived from the parameters link volumes, link lengths, and journey times. 4.2.5 Economy impacts model interface No specification is available for the economy impacts model input data requirements. It is assumed that the required data (if any) can be derived from the parameters link volumes, link lengths, and journey times. 4.3 Data Exchange Processing of the results of traffic assignments usually cannot be done manually, as one has to deal with parameters and indicators from thousands of links. Within the Windows environment there are basically two methods available for a communication between VISUM and other programs: Clipboard: VISUM can generate lists of indicators and assignment results. The user can select the items which should be included in such a list. This list can be stored as an ASCII file or copied into the clipboard and then imported to other applications, e.g. spreadsheets or data base applications. COM interface: this feature allows the access to the data structures of the transport model software with Visual Basic applications. The user can control the application of the transport model software and extract and process data according to his requirements. PTV AG 07/00 page 22/25 Error! No text of specified style in document. 5 Conclusions and Outlook Discussions with the city partners in the SUTRA project have shown, that the transport model software is able to simulate the possible scenarios and to produce the data required from the other models. Work on multi-modal transportation modelling will continue in SUTRA with establishing demonstrators for the features described in this deliverable in various test sites. These activities will be documented in the deliverables D03.2 Transportation Model Prototype D03.3 Transportation Model: User Manual and Example Test Data Sets Features of Test Sites Buenos Aires Gdansk Area-wide road user charging, Public transport fare strategies Geneva Genoa Road user charging in the city centre Lisbon Tel Aviv Parking policies, Road user charging (Congestion Pricing) Thessaloniki Public Transport Improvements: Underwater vehicle tunnel which links the west entrance of the city with the center and extension of it to the East Basic subway line in the center of the city PTV AG 07/00 page 23/25 Error! No text of specified style in document. Tramway in the center of the city, east and west Thessaloniki. Suburban railway linking the industrial area of Thessaloniki with the west part of the city. Private transport Improvements: Upgrading of the major arteries Upgrading of the other types of roads (ring roads and suburban roads) PTV AG 07/00 page 24/25 Error! No text of specified style in document. 6 References [1] Barbier-Saint-Hilaire, F., M. Friedrich, I. Hofsäß, W. Scherr : TRIBUT – a Bicriterion Approach for Equilibrium Assignment. Traffic Engineering & Control, April 2000. [2] Fellendorf, M., T. Haupt, U. Heidl, W. Scherr: ptv vision: Activity-Based Demand Forecasting in Daily Practice. In: Activity-Based Approaches To Travel Analysis, Elsevier, Oxford 1997, pp 55-72. [3] Lohse, D. : Traffic Assignment. In Schnabel, W., D. Lohse (ed.), Grundlagen der Straßenverkehrstechnik und der Verkehrsplanung, Berlin (1997), vol. 2, pp 317-325. [4] U.S. Department of Commerce, Bureau of Public Roads (ed.): Traffic Assignment Manual. Washington, D.C. (1964) [5] Wardrop, J. G. : Some Theoretical Aspects of Road Traffic Research. Proceedings of the Institute of Civil Engineers, London (1952), pp 335 ff [6] anon., Department of Environment and Planning, University of Aveiro [ed.] : TREM – Transport Emission Model for Line Sources – Methodology. 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