Georgia Aifandopoulou, Teti Nathanail, Demetrios Panayotakopoulos

ETIS : A GIS technology based tool for supporting strategic environmentally friendly planning of urban transport infrastructure development

1. Introduction

Strategic transportation planning for an urban area constitutes a complicated process which requires extensive data collection and analysis, and the implementation of a number of travel demand forecasting, environmental assessment models and evaluation methodologies.

At present, there is a number of available software packages supporting individual tasks of the strategic transportation planning process. However, these tasks, heavily interrelated to each other, indicate the need for an integrated computer environment which facilitates the overall planning process by providing automated data exchange among the packages, scenarios development and simultaneous evaluation of the results obtained by each package.

ETIS (Environment Transport Integrated planning System) constitutes a state-of-the-art system which supports the integrated application of all the tasks involved in the transportation planning process, i.e. travel demand forecasting, development of alternative transport infrastructure and policy scenarios, evaluation of the socioeconomic, traffic, and environmental impacts of the scenarios, cost-benefit analysis, comparison of alternative scenarios, and graphical representation of the involved evaluation indices.

The system has been developed by the TransEuropean Consulting Unit of Thessaloniki (TRUTh S.A.) for the purposes of the EEC financed study (PHARE No. 604/91) entitled "Master Plan Study for an Environmentally-friendly Transport System in Budapest" undertaken by the company. The study included the development of travel demand forecasting models and the testing and evaluation of different alternative Transport Infrastructure development schemes for the city. The time horizon of the planning process was extended to the year 2010. The consultant undertook the task of developing alternative test-networks and evaluate them on the basis of the impacts the proposed infrastructure development may have to the traffic conditions of the city and the environment.

Finally the prioritisation of the proposed developments was based on the predicted economic benefits and costs associated with them. This last task imposed the expression of environmental impacts of each scenario in monetary terms, fact which directly led to the calculation of evaluation indices which are not taken into account by the conventional traffic impact and environmental assessment forecasting tools. The integration of the ArcInfo functionalities in ETIS was made in order to support the calculation of these specific evaluation indices and to provide decision support for transport infrastructure development.

2. Main Issues of the Strategic Transportation Planning

Strategic Planning of Urban Transport Infrastructure Development has always been a critical issue for decision makers since it involves :

• analysis of the interrelation between land use and transport infrastructure development
• travel demand forecasting and modelling
• formulation of alternative transport infrastructure development scenarios
• assessment of the impacts of the scenarios on the traffic and environmental conditions of the study area.
• evaluation of alternative solutions which includes prioritisation of the objectives and measurement of the performance of the solution for achieving the objectives.

Transport Planners involved to strategic Environmentally friendly Planning of Transport Infrastructure are usually conformed with time consuming and respective tasks, which involve :

• handling of big volume of data (i.e. socio-economic data, land use data, transport cost data etc.) used for Traffic modelling and forecasting,
• creation of transport infrastructure supply inventory (including all geometrical and operational characteristics of the Road and Public Transport network)
• specification of alternative solutions, (sets of road and Public Transport Infrastructure with all the operational characteristics the planner desires to test on them)
• calculation of indices for assessing the impacts of alternative proposals,
  • traffic indices are: V/C ratio, traffic flow, delay, transit time between specific OD pairs, Total passenger-Kms, Total passenger-hours on the network etc.
  • environmental indices are: emission rates by link, noise levels by link, population exposed to different pollution and noise levels, percentage of urban surface where pollution conditions have been improved.
• testing of alternatives scenarios and evaluation of the results (calculation of traffic and environmental conditions)
• presentation of results and justification of the proposed solutions (compare traffic and environmental results)

For supporting some of the specific tasks of the above mentioned planning process specialised software packages are available, for Traffic modelling (EMME/2, MOTORS etc.) and Environmental Impact assessment (PAL, MARS, MEMO, etc.). Although this type of software packages are usually implemented parallel for the purpose of the Transport Infrastructure planning process, they have never been integrated in a single computer environment in order to provide assistance during all the steps of the planning and decision making process related to the Transport Infrastructure development.

Since the different types of data involved in the Transport Infrastructure Planning process follow a spatial distribution i.e. refer to geographical entities such as links, nodes, areas (zones), the application of GIS technology for developing an Integrated Transportation Planning Tool with special attention to the Environmental Protection is more than evident.

3. The ETIS Architecture

ETIS constitutes a computer environment in which ArcInfo workstation version 6.1.2 (Geographical Information System), EMME/2 workstation version 6.0 (Traffic Modelling Software), and PAL workstation version 2.1 (environmental pollution model) has been fully integrated for supporting:

• Planning of Transport Infrastructure and
• Management of transport operations in urban areas (i.e. Management of Public Transport Networks).

Since each one of the above software packages provides functionalities for supporting the same type of user generations (such as Transportation network description, results' presentation, etc.), it was critical for the ETIS design to assign specific roles to each one of the integrated software which corresponds to the support of concrete steps of the considered Planning Process. The role allocation among the integrated software application presented in the following paragraphs was based on :

• the evaluation of the efficiency and user friendliness of the functionalities provided by each software package for a specific task i.e. data modelling
• the minimisation of the necessary data transfer and data conversion actions throughout the process
• the facilitation of data updating.

The role of each software package as a component of the integrated architecture can be identified as follows:

• ArcInfo handles all geographical and descriptive data related with the areas of the city involved in the Planning process and also the data related with the geometrical and operational characteristics of the Public Transport and Road Network. It also supports the evaluation of the traffic and environmental results for each scenario of the transport infrastructure development scheme and the comparative presentation of these results.
• EMME/2 supports the modelling and forecasting activity i.e. the estimation of traffic volumes on the proposed transport Infrastructure, based on the forecasted evolution of socio-economic indices of the urban area, the transport cost predicted for the specific time horizon and also the modal split patterns for this horizon.
• PAL software performs, on the basis of the traffic volumes estimated on each specific link by EMME/2, the calculation of the emission rates for each major air pollutant and also the emission concentrations of the study area.

The overall system architecture is presented in figure 1.

Figure 1. ETIS Architecture

3.1 Database design

Taking into account that EMME/2 and PAL application have their own internal database structure the integration of them with ArcInfo was based on the development of an Integrated Data Base Management System and specific interfaces for data transfer and conversion.

The ETIS database structure is shown in figure 1. It comprises :

• external database including network functional and descriptive data, historic of traffic and socio-economic, and environmental data in different data formats (ASCII files, DBASE files etc.)
• ArcInfo Database organised in different layers for road Network, Public Transport Networks, alternative zoning systems, alternative infrastructure development scenarios. The geographical database comprises geometrical and functional characteristics for each link, node and zone involved in the network Management Process.
• EMME/2 database organised according to the EMME/2 internal data structures, comprising network descriptive characteristics, public transport transit lines, functional characteristics, origin- destination demand matrices, traffic forecasting models expressed as mathematical functions.
• PAL database including orography data, weather conditions data, summary of network descriptive data, emission and concentration pollution level prediction models, in the format of mathematical functions.
• Geographical database of results including the appropriate data structure for storing traffic and environmental results for each transport network development scenario.

3.2 ETIS functional modules

The Operational diagram of ETIS is shown in figure 2.

Figure 2. ETIS Operational Diagram

The functional modules of ETIS has been formulated as follows :

• NETWORK MANAGER : Developed fully in ArcInfo Environment, by using ArcInfo macro language, this module supports data manipulation for automatic creation of test-networks (alternative sets of Road and Public Transport Proposals), for which the planner wishes to estimate and evaluate the traffic and environment impacts on the urban area under study. The module supports data entry, proposals selection and illustration of the network of different modes (Road / Bus Network / Tram Network / Metro Network / Pedestrian Network / Parking areas etc.). The module also creates automatically the data structure required for the successive steps of the Traffic Modelling and Forecasting process.
• ArcInfo to EMME/2 interface : Developed in ArcInfo AML and C programming languages, this module transforms the data stored in the ArcInfo data base and creates automatically the input files for EMME/2 in the appropriate format. This data conversion eliminates errors usually occurred when the EMME/2 data base is formulated manually and from scratch every time a test network is to be checked.
• EMME/2 Traffic Modelling and Forecasting module. This is a macro file easily addressed by the user, comprising series of EMME/2 macro commands which read the necessary EMME/2 input process files, performs matrix calculations involved in each step of the traffic forecasting (trip generation/ trip distribution / modal split) and runs the corresponding EMME/2 modules for traffic assignments. The macro files give the capability to the user to estimate the travel patterns of the city for different time horizons. The knowledge of the socio-economic and land-use indices of a considered time horizon is a prerequisite for the implementation of the travel forecasting models incorporated in the EMME/2 macros. Based on the future socioeconomic indices provided by ArcInfo, the macro estimates the passenger trip productions and attractions and reserves this information for the implementation of the trip distribution, modal choice, and trip assignment models incorporated in this ETIS module.
• The EMME/2 to ArcInfo Interface. This module converts the EMME/2 output files in ArcInfo format and inserts them automatically in the ArcInfo data base in order for them to be used by the next modules for test network comparison and results’ presentation in graphical format.
• Environmental Conditions estimation module. This module consists of two specific parts the air quality module (PAL) and the noise level estimation module (developed in ArcInfo) environment. The module calculates emission rates and noise level by link. It also calculates concentrations of the main pollutants for each considered test network, over the study area.
• Test Network Evaluation module. Developed in ArcInfo environment, this module uses the already stored in the ArcInfo data base results of each test network and calculates evaluation indices such as population exposed to different levels of air and noise pollution, population for which trip duration for reaching specific land uses has been reduced by 10/15/20% etc. The module is also capable to present in electronic coloured maps comparative results of the test networks according to the specific queries of the user. Figures 3 and 4 illustrate examples of the developed menus of the ETIS Evaluation module.

4. ETIS application to the Budapest Environmentally friendly Transport Infrastructure development Study.

ETIS has been used for the Budapest Transport Master Plan Study and provided valuable assistance for decision making in a very conflicting decision making process which was constrained by the limited budget available for Transport Infrastructure Investment in the city. ETIS provided quick and valuable answers to the following questions:

• Which Transport Infrastructure projects to consider for the Transportation System Development?
• What traffic flows and Environmental conditions will result by the realisation of each set of Transport Infrastructure development?
• Which scenario is more beneficiary from the point of air quality, noise, and traffic conditions improvements throughout the Transport and the city environment?
• Given the limited financial resources which priorities apply to the infrastructure developments?

The actions undertaken by ETIS in the context of the Transport Master Plan Study of Budapest can be listed as follows:

• development and calibration of the Traffic forecasting models for the city
• development of detailed transport supply inventory for all active modes in the city
• Network formulation and testing: One of the main benefits of the system is the ability it provided to the planner for the development and testing of a large number of alternative scenarios. Minor or major changes on the network infrastructure, parking spaces and policies, operational characteristics of the various modes operating in Budapest, traffic calming and environmental alert policies were modelled, using the functionalities of ArcInfo. ETIS automatically adjusted all the updated information, converted it to the format required by the traffic, environmental, and evaluation models, and computed the indices which set the planner able to obtain measures of performance of the overall transportation system and the individual proposed developments.

  All the resulting indices were produced in a comprehensive graphical form, in order for analysts and decision- makers, regardless of their scientific background, to be able to draw conclusions. Initially, eight alternative scenarios for the Transportation System were tested, three of which were selected for further analysis and evaluation. The evaluation relied on traffic (e.g. travel time, travel delay, speed), environmental (CO, HC, and NOx emission rates and concentration, noise level), social (time loss, number of people affected by the pollution, accessibility, and costs involved) and economic (construction, maintenance, operational, land acquisition cost) indices for individual links, facilities, areas, or systems. Also, combination of the results was achieved (e.g. pollution per unit length, number of inhabitants exposed to a certain level of pollution, travel time contours from a certain zone and population within each contour). Figure 3 is an example of the maps created by ETIS to demonstrate the proportion of population exposed to different levels of pollution.

Figure 3. Pollution levels and affected population in Budapest

• Comparison of alternative scenarios. The comparison of alternative scenarios was enabled through the implementation of ETIS, and expressed in numeric figures or described graphically in coloured maps. An example of the comparison of the operational speeds between the road transport oriented and the public transport oriented scenarios is illustrated in figure 4. The colors indicate the levels of diference between the scenarios speed.

Figure 4. Speed comparison between alternative scenarios in Budapest

5. The Benefits of the ETIS Implementation in the Transport Infrastructure Planning Activities.

The benefits obtained by the Planning process from the ETIS integration of specialised application can be summarised in the following :

• exploitation of the advantages of each software package through their integrated use
• fast examination and evaluation of a big number of alternative infrastructure development sets by the user in the form of scenarios (i.e. change of data sets, change of basic parameters etc.)
• automatic transformation of data sets in the format of input files required by each software application used in the Integrated Environmentally friendly Transport Planning Process
• presentation of the results in a user-friendly way. The actual advantage is given by the advanced functionalities of the ArcInfo software
• real, and not abstract, representation of the zoning systems, and, also, of the road and the other networks (GIS software)
• easy and efficient update of the basic data such as network electronic maps, socio-economic data etc.

It must be mentioned that the functionalities made available by ETIS through the Integration of the GIS technology with specialised traffic and environmental impact modelling tools, provide the means for performing, at strategic planning level, both quantitative and qualitative evaluation of the impacts the alternative Transport Infrastructure development scenarios may have on the traffic and environmental conditions of the study area. The Evaluation module of ETIS provides to the planner and the decision makers sufficient information for justifying any decision at an early stage of the Planning Process which usually takes place in a very conflicting decision making environment.

6. Conclusions

A tool has been presented which facilitates the transport planner to model and evaluate alternative transport infrastructure and Transport policies scenarios. A number of existing software packages (including the more sophisticated traffic forecasting tool EMME/2), which support individual tasks of the planning process have been integrated in the ArcInfo environment, making use of the valuable GIS functionalities in order to fully exploit the capabilities of the individual packages. Specifically, a user-friendly menus lay-out has been created which calls a number of ArcInfo AML programs for data handling and analysis, evaluation indices calculation and result presentation.

The system has been successfully applied in the Budapest Environmentally friendly Planning of Transport Infrastructure Development providing variable results, reducing the time allocated to the Planning activity and facilitating the decision making process.