Public Transport Network Design and Appraisal - a case study of Porto Álvaro Costa, Pedro Abrantes, Oana Grozavu and Sílvia Magalhães CITTA – Centro de Investigação do Território, Transportes e Ambiente 10th EWGT Meeting, Poznan, 13-16th September 2005

Contents 1.Introduction 2.Re-designing Porto bus system 3.Network Appraisal Methodology 4.Impact of LRT Network 5.Impact of Strategic Bus Network 6.Local vs Global Accessibility 7.Global Efficiency Indicators 8.Conclusions 9.Further Research

1.1. Introduction Porto Metropolitan Area pop.: 1.2 mi New light rail system (Metro do Porto) New integrated ticketing system (Andante) Need to restructure bus network for greater integration and efficiency New network design based on “professional judgement” (heuristic method?) CITTA commissioned to: evaluate its public acceptability and efficiency suggest improvements where necessary

1.2. Introduction - OR analogy Starting point: existing STCP bus network (red) + metro (blue) 81 bus lines (to be cut down to 50) Problem: Guaranteeing public acceptability and increased efficiency while minimizing change I.e., heavily constrained problem, but poorly defined constraints Solution: Iterative, piece meal, client-driven approach (“trial & error”) to ensure feasibility of solution = optimization in the real world Strong emphasis on GIS analysis of results.

Change in bus service frequency (bue = increase) 2. Re-designing Porto bus system Design criteria: –Shorten lines –Modal integration –Homogeneous frequencies –80  50 lines Result: –17% veh-km reduction –Decrease in radial services –Increase in orbital services

3.1. Network Appraisal Methology Public Transport Assignment Model (EMME/2) Fixed demand from 2001 household travel survey Network Scenarios: –10: Bus0 –20: Bus0 + Metro –30: Bus1 + Metro –3x: Busx + Metro Accessibility analysis Efficiency analysis

3.2. Network Appraisal Methology Accessibility indicator (GIS plots) : Average generalized travel time by destination zone Efficiency indicators: Fleet size, Veh-kms, Total trips (operator) Pax-kms, travel time, walk time, number of interchanges (users)

4.1. Analysis of Results - Impact of the LRT Network Change in accessibility between scenarios 10 and 20 As expected, LRT brings about significant travel time reductions (up to 12 min) Greatest benefits along LRT Large gains up to a significant distance from LRT, because of bus-LRT difference in speed (25km/h vs 13km/h)

4.2. Analysis of Results – Impact of the LRT Network Change in bus passenger flows between scenarios 10 and 20 General reduction in bus pax flows Small increases in certain suburban/orbital routes Potential complementary role of bus in new network

5.1. Analysis of Results - Impact of the Strategic Bus Network Change in accessibility between scenarios 20 and 30 Significant travel time increases (≤ 8 min): poorer coverage or service transfer to private sector Significant gains in some suburban zones (≤ 10 min): improved LRT access, successful integration ☺ Gains from metro outweigh losses from new bus network in nearly all zones (special zones treated later) Policy implication  Metro + Bus1 must be introduced at same time

5.2. Analysis of Results - Impact of the Strategic Bus Network Change in bus passenger flows between scenarios 20 and 30 Reduction in radial flows, esp. around city centre, due to reduced frequency Significant increases in orbital flows, esp. towards main metro interfaces Explains gains away from LRT route  bus services play an important role as feeders to LRT

5.3.Analysis of Results – Impact on the pattern of trip interchanges Change in transfer boardings between scenarios 10 and 30 (red=increase) Concentration of intechanges around key metro stations Bus increasingly becomes a feeder mode to LRT. Bus-bus transfers decrease significantly Policy implications: –Improve interchange facilities to take full advantage of new mode –Minimize distance between bus and metro stops

6.1. Local vs Global Accessibility Problem: Some zones lose accessibility from sce. 10 to 30 Further investigation showed inconsistencies in network design: –Zones furthest away from metro miss out the most with the new bus network –Those zones also happen to be important centres for surrounding n’hoods Change in accessibility scenarios 1 to 3 Change in accessibility scenarios 2 to 3

Diagrams attempt to illustrate the problem The new bus network improves access to metro stations, which in turn greatly improve access to distant parts of the city Yet, reduced network coverage decreases local accessibility As we started by looking at the whole metropolitan area, this problem went nearly unnoticed Policy outcome: strengthen local bus services 6.2. Local vs Global Accessibility

7.1. Global efficiency indicators – User perspective 3% mean travel time decrease from sc. 10 to 20 Constant travel time from 20 to % mean travel distance decrease from sc. 10 to % mean travel distance decrease from sc. 20 to 30 Notice significant pax-kms transfer to metro due to new bus network (+10%)

7.1. Global efficiency indicators – User perspective Metro does not produce an increase in av. interchanges New bus network actually reduces interchanges But at the cost of greater walk access time Still, no increase in travel time

7.2. Global efficiency indicators – Operator perspective 14% decrease in fleet size requirements 4.2% decrease in morning peak hour veh-kms travelled Conclusion: Significant savings achieved, while maintaining or improving accessiblity by applying simple network design rules “Operator happy, passengers happy” Fleet sizeVeh-kms (AM peak hr) Bus_ Bus_ delta-14.4%-4.2%

8. Conclusions Useful methodology, popular with decision makers and public Benefits from LRT line are significant, and spread beyond the route Scale of benefits depends on bus service design  bus plays an important feeder role in the LRT network It is possible to achieve significant gains in accessibility by re-designing the bus system for better integration with LRT network Furthermore,it is possible to do this while improving efficiency (inc. fewer resources) Nevertheless there is a trade-off between local and global accessibility in some areas, which is not visible when analysing accessibility across whole area

9. Future research Incorporate elastic demand model Introduce outstanding operators and differentiated fare system Develop optimization algorithms to find the “optimum network” Test the impact of other policy measures, eg bus priority

Questions & comments Pedro Abrantes CITTA Faculdade de Engenharia da Universidade do Porto See presentation on from 20th Septwww.fe.up.pt/~pala