Evaluation of bus stop accessibility and determination of optimal locations for bus stops: a GIS based approach

Abstract

The efficiency and effectiveness of the transportation system is an essential ingredient to ensure quality of urban life. Public bus is an important component in the public transport system. It provides access to facilities, which contribute to social inclusion, thus becoming the backbone to a city’s performance. In most cities, bus is the main public transport system. In modern dynamic society, everyone should be able to access the bus system to obtain the benefits that it offers. In bus service, bus stop is an important component to consider. The mobility of public transport can be improved by a conscious and detailed design of every facility, and in the case of buses the key facility is the bus stop. Bus stops are key links in the journey of a bus rider. Inaccessible bus stops often represent the weak link in the system effectively preventing the use of fixed-route bus service. Physical, cognitive, and psychological barriers associated with bus stops can severely hamper bus ridership, thus limiting their mobility and potentially. So, bus stops in transportation networks should be designed in smart way to ensure an adequate coverage and quick accessibility to all users. The dominant mode of transportation in Dhaka is road based transport system where bus is the only mode of mass transit. But no study has been conducted in details up to now to understand the existing situation, determine the present bus stops’ accessibility, and to find out the optimal locations for bus stops. The main goal of the research is thus, to study the accessibility condition of existing bus stops located along some selected primary roads of Dhaka city where most of the public buses run and to determine the optimal locations of bus stops on a selected bus route. The study reveals the technique to evaluate the accessibility of bus stops on existing roads which helps to understand the existing accessibility conditions of bus stops. The study also identifies the optimal locations of bus stops based on several defined criteria which represent the locations where bus stops should have been located. Finally, a comparison between the results (i.e. accessibility of existing bus stops and optimal locations of bus stops) is taken places which identifies the poorly located existing bus stops (or risky bus stops) that should be relocated into better locations where higher accessibility can be assured. Three parameters are used in this study to assess the accessibility of bus stops, they are: Road density, Trip generation and Population served. After assessing the accessibility, it has been found that among existing bus stops, most of them have less accessibility; even accessibility index is found 50 percent or less for 65 percent bus stops (bus stops in both directions). Only 15 bus stops (bus stops in both directions) out of total 180 are found highly accessible and categorized as excellent stops according to the study. 25 percent bus stops (45 bus stops out of 180) are found having very little accessibility and categorized as poor stops which should relocate based on the optimal locations. 40 percent bus stops are categorized as moderate for having moderate accessibility index (33.3-50%) and need to be compared with the optimal locations in order to identify if there is any better locations to relocate. Places for optimal locations are identified by generating stops at 100 meter interval. Accessibility of generated stops is measured based on the same parameters considered before: Road density, Trip generation and Population served. Stops at and just around the intersections are omitted. Finally 888 remaining points are considered for optimal locations. It is found from the study that about 80 percent bus stops are found having very little accessibility and categorized as poor. Around 16 percent stops are found having moderate accessibility and the rest (only about 5 percent) is found as highly accessible. After relocating poorly located existing bus stops into optimal locations, proper measurements should be taken to improve the accessibility condition of bus stops. Therefore, some recommendations are proposed at the end of the study which might help to improve the accessibility of bus stop. ArcGIS software is extensively used at different stages in determination of the accessibility. The outcome of this research thus helps the policymakers to plan the “optimal location” of the new bus stops or to modify their location so as to serve most users in its urban setting.