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Modelling for Estimation of Demand to Generate Feeder Bus Routes of Mass Rapid Transit System Prof B R Marwah, Non-member Dr R Parti, Non-member With the introduction of a high capacity rapid transit system in a metropolitan city, the commuters from the existing public transport modes are generally attracted to the mass rapid transit system (MRTS) and the major portion of demand is from the existing bus transport system. In addition, the implementation of such a fast efficient transport system requires the feeder bus services for effective integration of the two modes. Planning of feeder bus transit system to integrate with mass rapid transit system (MRTS) necessitates the estimation of demand which will shift to the MRTS from the existing bus system. Delineation of influence area for MRTS stations and station loads. The present paper deals with the mode choice analysis to estimate the proportion of demand shifted from the existing bus system to the MRTS based on the logit model and is effectively implemented to New Delhi, the capital city of India. Keywords: Mass rapid transit system; Feeder routes; Demand; Integration; Logit model INTRODUCTION the mode choice analysis. To achieve this objective the study Feeder bus routes to high capacity Rail Transit Network play methodology has two important stages, namely, an important role in ensuring an integrated multi-model l Study of the existing road network, existing bus public transport operation. Implementation of such a system transit system and proposed MRTS network. will force the restructuring of existing bus network, and l Mode-choice analysis to estimate the passenger demand provision of feeder bus services for effective integration of the matrix for combined MRTS and feeder network. to integrate two modes. Planning of feeder bus transit system= a 0 + a1T _ time Bus + a 2T _ with mass rapid transit system (MRTS) requires estimation of Mode Choice Analysis demand, which will shift to the MRTS from the existing bus In a metropolitan city, the existing modes of public system, delineation of influence area for MRTS stations and transportation, before the introduction of MRTS, are station loads. Integration of high capacity transit system with generally in different forms of buses and intermediate public feeder public transport system therefore, needs a series a transport (IPT). With the introduction of a new public heuristic optimization models1. transport mode, some share of trip makers will shift from the The public transport system of Delhi2 is primarily road based existing bus system to the new public transport mode. with a mix of public and private buses. At present the regular Similarly, some portion of demand from private modes may bus system (stage carriage) comprises 6150 buses that carry also shift to the new system. However, the major component about eight million commuters. of the demand coming to MRTS will be one transferred from the existing bus transit system. Besides about 5000 chartered buses provide point-to-point 3 service during peak hours supplementing the regular bus Logit model from the family of mode choice models has been services. Public transport network is being improved and considered to split the travel demand between the existing bus expanded by including a MRTS for a route length of 33 km in transit system and the newly introduced MRTS. The utility the first phase. The commissioning of MRTS corridors started (or disutility) function is typically expressed as the linear from 2002 and all the sections are likely to be operational by weighted sum of the independent variables or their the year 2005. transformation. For sharing the inter stop travel demand between MRTS and bus transit network, utility measure of the STUDY METHODOLOGY two public transport modes is to be calculated. Measure of The basic objective is to estimate the travel demand matrix for utility, a function of travel time, travel cost, comfort, transfer the combined MRTS network and feeder bus services based on penalty etc, may be expressed as: UCBus = a 0 + a1T _ time Bus + a 2T _ costBus Prof B R Marwah is with the Department of Civil Engineering, IIT, Kanpur 208 016; and Dr R Parti is with the Department of Civil + a 3C _ fort Bus + a 4 trans _ plt Bus (1) Engineering, National Institute of Technology, Hamirpur, HP 177 005. UCMRTS = b 0 + b1T _ time MRTS + b 2T _ cost MRTS This paper is received on June 21, 2004. Written discussion will be received till January 31, 2005. + b 3C _ fort MRTS + b 4 trans _ plt MRTS (2) Vol 85, November 2004 169 where UCBus is utility measure of bus transit network; transfers are considered while planning for bus routes. For UCMRTS is utility measure of MRTS; a0, a1, a2, a3, a4 are utility determining the travel time between any node pair (i, j ) on an coefficients of bus transit network; b0, b1, b2, b3, b4 are utility existing bus route network, the inter-stop travel time is coefficients of MRTS; T_timeBus is travel time of bus transit estimated through (i) no transfer cases, (ii) one-transfer routes, network; T_timeMRTS is travel time of MRTS; T_costBus is and (iii) two transfer routes. travel cost of bus transit network; T_costMRTS is travel cost of Estimation of Inter-stop Travel Time through MRTS MRTS; C_fortBus is comfort level of bus transit network; C_fortMRTS is comfort level of MRTS; Trans_pltBus is transfer When the MRTS is newly introduced, the trip makers may penalty of bus transit network; and Trans_pltMRTS is transfer not be able to clearly judge the nearest possible MRTS stations penalty of MRTS. in the vicinity of their origin or destination. The approach to determine the best path through MRTS, as shown in Figure 1, is: The parameters of travel time and travel cost for MRTS systems would also include travel time and travel cost of (i) For each stop, determine five closely located MRTS feeder system. The data can be used to calibrate the stations, those with shortest distance from the stop. coefficients of the parameters. Once these utility measures are (ii) For a bus stop pair (i, j ) let there be MRTS stations calculated then proportion of demand on each mode is (mt1, mt2, mt3, mt4, mt5 ) in vicinity of stop i and let calculated using logit model. there be MRTS stations (nt1, nt2, nt3, nt4, nt5 ) in vicinity of stop j. e −UC Bus PBus = (3) (iii) To travel through the combination of MRTS and road e −UC Bus + e −UC MRTS between stops i and j, a total of 25 alternative paths are now available. Total travel times are estimated for e −UC MRTS PMRTS = (4) each of the 25 alternatives and one with least time is e −UC Bus + e −UC MRTS selected. where PBus, PMRTS are the proportion of demand of the bus Total travel time through mt1, nt1 = TT_road (i, mt1 ) + transit system and MRTS, respectively. TT_MRTS (mt1, nt1 ) + TT_road (nt1, j ) + transfer time at The utility measures of bus transit system and MRTS include station mt1 + transfer time at station nt1 (5). the parameters of travel time, travel cost and transfer penalty, where TT_road(i, mt1 ) is travel time along the road from stop i which need to be determined. Firstly, the various parameters to MRTS station mt1 ; TT_road( j, nt1 ), travel time along the with respect to MRTS are to be calibrated. The mode choice road from stop j to MRTS station nt1 ; and TT_MRTS (mt1, analysis determines the proportion of demand between the nt1 ), travel time along MRTS between stations mt1 and nt1. two modes for each origin and destination node pair. It is therefore, desirable to calculate the travel time and travel cost Minimum of the Total Travel Time for 25 alternative paths for each node pair for both the public transport modes. establishes the best path to travel through MRTS. Estimation of Inter-stop Travel Time by Existing Bus Routes Accessibility of the various inter-node transfer with respect to The existing bus transit system in the city may have a large the MRTS are determined through two incidence matrices number of bus routes serving the stops. A trip maker may able [con_mrts(i, j )] and [sec_mrts (i, j )]. If inter-nodal transfer to perform a trip between an origin and destination either between i and j use MRTS system then [con_mrts (i, j )] depicts through a directly connected route or by a series of bus routes the connectivity between the node i and MRTS station and with some transfers4. As it may not be feasible to provide [sec_mrts (i, j )] gives the connectivity between the second direct bus routes between each O-D pair, normally up to two MRTS station and node j. Stop[ j] mt1 mt2 mt3 mt4 mt 5 MRTS corridor nt 1 nt2 nt3 nt 4 nt 5 Bus Route Stop[i] Figure 1 Estimation of inter-stop travel time 170 IE (I) JournalCV Road network MRTS network Demand of matrix for characteristics characteristics public transport Existing bus routes Pessimistic approach Optimistic approach characteristics Inter-stop shortest travel Inter-stop travel time through time through directly existing bus routes by connected bus routes Directly connected bus routes One-transfer routes Two-transfer routes Identification of shortest time for inter-stop transfers through road network or combined MRTS and road network Availability of feeder bus Availability of feeder bus routes at one end of MRTS routes at both ends of MRTS Fare for: Fare for: Fare for: Fare for: MRTS and feeder MRTS and feeder MRTS and bus Unified MRTS services services system and feeder —unit rate —slab rate —unit rate services Bus system Bus system Feeder rate —unit rate —slab rate services Bus system —unit rate —unit rate Demand matrix for For an inter-stop transfer between MRTS node pair (i, j), obtain Connectivity matrices Share matrix Demand matrix for road network Figure 2 Model for mode choice analysis Application of Mode Choice Analysis Model (iv) Availability of feeder routes on one end or both ends. Mode choice analysis model, as shown in Figure 2, is evolved Considering the inter-nodal transfers between existing bus to assess the number of commuters who may shift from the transit system and MRTS/feeder bus service, the utility existing bus system to MRTS-feeder bus combination based on measures for each of the two modes is estimated. The total the parameters of travel time, travel cost and modal travel time by the existing bus system and by the best possible characteristics of the two modes. A commuter may opt to path from the 25 different combinations of MRTS stations and travel through MRTS subject to the conditions: O-D nodes is estimated. Accessibility of the inter-nodal transfers with respect to the MRTS is established and (i) Maximum distance from the origin or destination to accessibility materials are calculated. the MRTS station from where demand can be Optimistic approach deals with limited existing bus transit attracted and feeder routes are to be generated should network that is already available whereas pessimistic approach be within a certain limit. deals with unlimited bus transit network. The model (ii) The distance travelled on MRTS corridor should facilitates eight options for both the approaches based on the be at-least some proportion of the total distance combinations of bus fare system, MRTS and feeder bus travelled between the origin and destination nodes. system, availability of feeder bus service either on one end of (iii) The distance travelled on the MRTS corridor is MRTS or on both ends. Table 1 presents the options available greater than a certain minimum distance. in the model for the analysis of mode choice. Vol 85, November 2004 171 Table 1 Options available for mode choice analysis The mode choice analysis between any O-D pair involves the estimation of Option Existing/ MRTS and feeder Availability number unlimited bus system of feeder (i) In vehicle travel time from origin to destination. bus system MRTS fare Feeder bus service (ii) Transfer time at MRTS stations. fare bus fare (iii) Waiting time on the bus and MRTS system. 1 Unit Rate Unit Rate Unit Rate One end (iv) Travel cost through bus and MRTS/feeder system. 2 Unit Rate Unit Rate Unit Rate Both ends As the mode choice model assigns the demand between 3 Slab system Slab system Slab system One end MRTS/feeder system and bus system, the value of different parameters assume considerable importance. To test the 4 Slab system Slab system Slab system Both ends sensitivity of the model with respect to different parameters 5 Slab system Inter MRTS- Slab system One end and decision thresholds, the parameters, which are of station fare considerable importance in mode choice, that need to be matrix studied under different scenarios are: 6 Slab system Inter MRTS- Slab system Both ends l Policy time headway for feeder bus routes. station fare l Maximum distance from MRTS station from where matrix demand is attracted to MRTS. 7 Slab system Unified MRTS One end l Minimum ratio of MRTS travel distance to total and feeder bus travel distance between origin and destination. fare (Inter-stop l Availability of feeder service at one end or both ends. unified fare matrix) l Type of fare structure slab system or unit rate. 8 Slab system Unified MRTS Both ends Table 2 gives the values of different parameters adopted for and feeder bus sensitivity analysis. In this table, each of the parameters at fare (Inter-stop serial 3, 5 and 7 have three values; those at serial 8 and 9 have unified fare two values, while others have only one value. A full factorial matrix) design for these values will result in 108 combinations. Mode Considering these operational constraints, the mode choice Table 2 Value of parameters for mode choice analysis analysis estimates the share of demand between the bus transit network and MRTS/feeder bus service for each O-D pair. The Serial Parameters Values proportionate share of inter-nodal demand through MRTS is Number determined by the formulated Logit model and matrix 1 Transfer time from feeder [share_mrts (i, j )] is generated. If there is a feasible path to MRTS, s 300 through MRTS between i and j, then share_mrts (i, j ) lies 2 Transfer time from MRTS between 0 to 1, otherwise share_mrts (i, j ) = 0. to Feeder, s 300 Application of Mode Choice Analysis for New Delhi 3 Time headway for feeder The demand is estimated for generation of feeder route plan in bus routes, s 300, 600, 900 accordance with the data available from Rail India Technical 4 Time headway for MRTS and Economical Services. The daily demand matrix for inter- routes, s 300 stop demand of (1542 × 1542) size represents total demand of 7.67 million passengers for the year 2000. For the 5 Maximum distance (in km) from metropolitan city of Delhi, the share of public and private MRTS station from where demand transport mode data is available and 62% of the travellers is attracted on to MRTS 8, 10, 12 move through public transport. In this paper, the study is 6 Minimum distance travelled on restricted to only two parameters of travel time and travel MRTS, m 2000 cost, because the realistic data is available only for these two 7 Ratio of MRTS travel distance to parameters. Analysis was done with the estimated coefficients total travel distance between origin for different trip lengths and trip cost between public and and destination 0.2, 0.3, 0.4 private mode. Knowing the number of travellers for different trip lengths, the total share of public transport system is 8 Availability of feeder bus service One end, both ends estimated. This analysis helped to calibrate the coefficients of 9 Fare structure Slab rate, unit rate travel time and travel cost. 172 IE (I) JournalCV choice analysis is carried out for these 108 cases to study the from 12 km to 8 km and increasing ratio of MRTS travel behaviour of the model under different scenarios. distance to total distance between O-D pairs from 0.2 to 0.4, the daily MRTS rider-ship will decrease from 1.82 million to The fare structure considered for sensitivity analysis is slab 1.24 million, a drop of 31.87%. For the cases, when the feeder system and unit rate/km. service is available only at one end, the rider-ship is estimated Application of the mode choice model for a scenario estimates to range between 1.65 million and 1.16 million. the expected MRTS rider-ship for each O-D pair and the total Estimated MRTS demands for different scenarios indicate that MRTS demand matrix (1542 × 1542) is generated. These the formulated mode choice appears to give realistic results. matrices are generated for all the 108 cases of experimental The estimated MRTS demand matrix obtained from the mode design. Study of these results indicate that choice model is to be used for planning of the feeder bus l MRTS rider-ship decreases as the time headway for network. the feeder system increases from 300 s to 900 s. This is because higher time headway increases the travel time SUMMARY making MRTS less attractive. This paper deals with mode choice analysis to estimate the l MRTS rider-ship increases as the influence area for proportion of demand shifted from the existing bus system to MRTS increases from 8 km to 12 km. If feeder service the MRTS based on the logit model and is effectively is provided for longer distance, it will have more implemented to New Delhi, the capital city to India. The attraction to MRTS. coefficients of parameters for travel time and travel cost is l As the minimum travel distance over MRTS, estimated based on the modal split for public transport in expressed as ratio of the total trip length, increases Delhi. To test the sensitivity of the mode choice model with from 0.2 to 0.4, the MRTS rider-ship decreases. respect to different parameters and decision thresholds, the various parameters, which are of considerable importance, are l When the feeder service is available only at one end of studied under different scenarios. the trip, MRTS rider-ship will be less as compared to when service is available at both ends. REFERENCES These trends are similar for both types of fare structure. In case 1. P Raman. Bus Transit Planning for a Large City and Decision Support of slab fare structure, the highest daily MRTS rider-ship of System of Feeder Bus Routes for Rail Transit Network. Ph D Thesis 1.82 million is estimated when (unpublished work), IIT, Kanpur, September 2002. l Feeder routes have time headway of 300 s. 2. RITES. Planning of Feeder Public Transport System for Phase-I of Delhi l Maximum distance from MRTS station to stop within MRTS. New Delhi, India, 2001. which demand can be attracted is 12 km. l MRTS travel distance is at least 0.2 times the total trip 3. C S Papacostas. Fundamentals of Transportation Engineering. Prentice-Hall length between O-D pairs. of India Private Limited, New Delhi, 1990. l Feeder routes are available at both ends. 4. M H Bajj and H S Mahamassani. TRUST: a LISP Program for Analysis of With increase of time headway for feeder routes from 300 s to Transit Route Configurations. Transportation Research Record 1283, 900 s, decreasing maximum distance of MRTS station to steps Transportation Research Board, Washington, DC 1990, pp 125-135. Vol 85, November 2004 173

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