Public Transport Versus Private Car: GIS-Based Estimation of Accessibility Applied to the Tel Aviv Metropolitan Area

Transcription

1 Public Transport Versus Private Car: GIS-Based Estimation of Accessibility Applied to the Tel Aviv Metropolitan Area Itzhak Benenson 1, Karel Martens 3, Yodan Rofe 2, Ariela Kwartler 1 1 Dept of Geography and Human Environment, Tel Aviv University 2 J. Blaustein Institutes for Desert Research, Ben Gurion University in Negev 3 Institute for Management Research, Radboud University, Nijmegen

2 Accessibility and Equity Lack of physical access decreases the range of opportunities and is a cause of social exclusion Lack of access is primarily problem of car-less households Tool is needed to measure access levels for car-owning and car-less households to asses scope of access problem

3 What is accessibility? The extent to which land-use transport system enables individuals or goods to reach activities or destinations by means of transport modes* Given a destination: The amount of effort necessary to reach a destination Given an origin: The number of destinations/activities that can be reached from there, given the amount of effort *K.T. Geurs, J.T. Ritsema van Eck, 2001, Accessibility measures: review and applications, RIVM report , Urban Research Center, Utrecht University

4 How do we measure accessibility components? Transportation: Bases on transportation system performance (travel time, cost, effort to travel between origin and destination) Land-use: Based on distribution of activities (jobs, schools, shops) and population (workers, pupils, customers) in space and time Individual, utility-based: Based on needs and benefits people derive from the access to facilities

5 Gravitation model and its generalization are yet most popular Accessibility of activity J (jobs) from location i A = n j= 1 J j d ij β β J j d ij - Distance decay rate - Activities (jobs) at j - Distance between i and j Numerous generalizations combine different dimensions of the problem into one index and, thus, are problematic Weibull (1976) A i P i O j D j F( d ij ) - Job potential at i - Population potential at i - Population at j - Jobs at j - Distance decay function

6 Transportation component is the one commonly accepted (and very practical) How many people can reach the given location by train (for a given amount of effort)? Example of transport accessibility

7 How many activities can be reached from the given origin (for a given amount of effort)? Example of transport accessibility

8 We estimated the transport component of accessibility in Tel Aviv metropolitan area

9 Street network Attributes: traffic directions, speed Sufficient to measure accessibility by car

10 Bus lines Bus stops Relation between bus lines and stops. Necessary component for measuring bus accessibility

11 Bus time-table Necessary for measuring bus accessibility

12 Urban land-uses Land-uses No of jobs by traffic zones Necessary for measuring activity component of accessibility

13 Car ownership Population numbers by traffic zones Socio-economic level Socio-economic level by traffic zones Sufficient to measure demand for bus accessibility

14 Exact definition of transport accessibility Bus Travel Time (BTT): BTT = Walk time from origin to a stop of Bus 1 + Waiting time of Bus 1 + Travel time of Bus 1 + [Transfer walk time to Bus 2 + Waiting time of Bus 2 + Travel time of Bus 2] + + Walk time from the final stop to destination Car Travel Time (CTT): CTT = Walk time from origin to the parking place + Car trip time + Parking search time + Walk time from the final parking place to destination. Service area: Given origin O, transportation mode M and travel time τ define Mode Service Area - MSA O (τ) - as minimal area containing all destinations D that can be reached from O with M during MTT τ. Access area: Given destination D, transportation mode M and travel time τ define Mode Access Area MSA D (τ) - as minimal area containing all origins O from which given destination D can be reached during MTT τ. We thus distinguish between Bus Service Area BSA O (τ), Bus Access Area BAA O (τ), Car Service Area CSA O (τ), Car Access Area CAA O (τ)

15 We focus on measuring relative accessibility (i.e. ratio between areas of service/access by public transport and car) Service areas ratio: SA O (τ) = BSA O (τ)/csa O (τ) Access area ratio: AA D (τ) = BAA D (τ)/caa D (τ)

16 Urban.Access application

17 Urban.Access parameters Day of the week Trip start/finish time Max time of waiting at initial stop Walk speed when changing lines Max travel time Calculate access area Max number of line changes Calculate service area

18 Stops one can reach during τ service/access area

19 Area accessibility urban land-uses accessibility

20 Accessibility maps for Tel-Aviv metropolitan Relative accessibility decreases twice the metropolitan center to periphery! (One of the major goals of the transit system is to connect between the center and periphery )

21 Access Area indices (AA D,Employment (τ) indices), for employment destinations in Tel-Aviv metropolitan, 7:00h versus 12:00h In Tel Aviv metropolitan With the car you can reach four times more jobs than with the bus With the direct bus you reach 10 time less jobs than with the car Areas essentially differ in relative accessibility

22 Accessibility gaps in Tel-Aviv metropolitan There are areas within the city with very low accessibility. These areas emerge because nobody thinks about accessibility when managing bus network. The only criteria of a bus companies is the number of passengers in a bus, to make the line profitable. In addition, the demands of the bus-drivers trade-union makes the system extremely conservative.

23 Main reason of low relative accessibility: low frequency of buses The analysis of the results clearly manifests that the main reason of the low relative accessibility is a long waiting time, both at the start and at the transition stops What might be the reasons for transportation planners to preserve this ineffective time-table?

24 Bus company: Increase intervals between departures, for full exploiting bus capacity Passenger: Less certain bus arrivals, especially during peak hours reduced relative accessibility Vicious loop of public transportation systems dynamics Passenger: Further avoid use of buses if they have choice Bus company: Vague timetable at stops aimed at preventing complaints High frequency of all lines, provides high accessibility, serves all population groups (Curitiba) Should be established at once, otherwise costly and highly vulnerable during transition period One-way evolution of the transportation system Adaptive frequency of lines, provides average accessibility, serves non car-owners only (Tel Aviv) Robust, self-regulating, preserves reasonable level of profit

25 Thank you!