Geographic accessibility analysis and evaluation of potential changes to the public transportation system

Abstract

Modern public transportation systems are required to be more efficient. The efficiency and the quality of the service is based on several aspects, such as availability, frequency, travel speed, reliability and safety. Stop spacing system is a significant part of the public transport service design and it deeply affects its efficiency. In particular, the stop spacing system has consequences on the accessibility, access and egress time, travel speed, transit time and the operating costs.

The purpose of this study is to propose potential changes to the surface public transportation system in the City of Milan to create a more efficient service. In particular, the study aims to analyze what happens if the stops spacing system changes, increasing the distance between the bus stops. The model developed in the thesis was created working on the distance between consecutive stops and the introduction of three new potential stop spacing systems, with a target distance between the stops set to 400, 500 and 600 meters. The model is mainly based on three different steps: (i) select the stops that could not be moved or eliminated because of the importance of their location; (ii) select the stops that could be moved or eliminated; (iii) relocate the stops considering the target distance between the stops (400, 500 and 600 meters).

According to the model, eliminating some of the stops could have a positive effect on travel times and operating cost reductions. In particular, changing the stop spacing system eliminating an average of 1.7, 2.5 and 3.4 stops per route for the three model scenarios (respectively 400, 500 and 600 meters of target distance between the stops), would decrease the travel time by respectively, 3.0%, 4.4% and 5.7%. Results also indicate that in an optimal situation, with traffic light priority and public transport fast tracks for public transport vehicles, the travel time could decrease by 3.9%, 5.8% and 7.6%. The operating costs analyses indicate that the three different scenarios could reduce the annual cost per km by about 0.5%, 1% and 2%.

The evaluation of the effects of the proposed potential changes to the surface public transport stop spacing system was also made analyzing the mobility demand and the accessibility. In particular, the network analyses made on the mobility demand show that the travel time averagely decreases by 1.6%, 1.9% and 2.2%, the transportation time decreases by 2.0%, 3.7% and 5.0% and the pedestrian time changes by -0.4%, +2.8% and +5.2% for the three model scenarios. In terms of minutes, the pedestrian time is balanced with a more efficient surface public transport system. The raster analyses made on the accessibility, using a model called PTAL, shows that the accessibility level didn’t change for 94.2%, 91.1%, 89.9% of the cells and that it is lowered just by 1.0%, 1.5% and 1.9% of the cells.

The model developed in the study is merely theoretical and it generally gives positive and interesting results in terms of efficiency. However, to be able to understand its real efficiency it is necessary to make other studies on a closer scale.

Popular Abstract

In a society which aims to make a major step in the direction of sustainability, it is necessary to promote efficient alternative modes of travel in the automobile-dominated urban travel markets. In this study, potential changes to the surface public transportation system in the City of Milan are evaluated. Surface public transportation system can be considered unattractive because of its lack of efficiency. One of the possible reasons that the service is not efficient is the placement of the stops. Stop spacing is a significant part of the public transport service design as it affects passengers’ walking time as well as the operating speed of a route, which affects both transit time and operating costs. A densely spaced public transport station obviously improves the geographic coverage and the accessibility, but it also increases in-vehicle time and supply costs. On the contrary, eliminating service stops speeds up the system and reduces the operating costs.

In the study, new stop spacing models are evaluated with the purpose to get the service more efficient by increasing the distance between the stops. Working on a broad scale, the model has been created for three different scenarios, with a target distance between the stops set to 400, 500 and 600 meters. Results indicate that eliminating some surface public transport stops (an average of 1.7, 2.5 and 3.4 stops per route for the three model scenarios) could reduce the travel time spent on the service by, respectively, 3.0%, 4.4% and 5.7%. Results also indicate that the travel time could decrease more in an optimal situation, with traffic light priority and public transport fast tracks for public transport vehicles. The operating costs analyses show that the three different scenarios could reduce the annual cost per km till about 2%.

In the study, the analyses made on the mobility demand and on the accessibility were used to evaluate potential effects on the reality of the proposed changes to the surface public transport stop spacing system. In particular, it is evaluated that, in the proposed scenarios, the accessibility level does not change for the majority of the areas and that the areas where the accessibility level improved are more than the ones where it is lowered.

The model also has positive results on the mobility. In particular, simulating about 1300 urban movements, allowed to evaluate how the pedestrian time, the time spent on the service and the total travel time could potentially change. In particular, the total travel time and the time spent on board decrease and they decrease the more the distance between consecutive stops increases. On the contrary, the pedestrian time increases the more the distance between the stops increases, but a longer pedestrian time is balanced by a shorter time spent on board.

• author: De Martino, Alessandro
• supervisor: Lars Harrie
• organization: Dept of Physical Geography and Ecosystem Science
• alternative title: Changes to the public transportation system in the City of Milan
• course: GISM01 20142
• year: 2014
• type: H2 - Master's Degree (Two Years)
• subject: Earth and Environmental Sciences
• keywords: stop spacing system, public transport stops, public Transport, GIS, PTAL’s, Physical Geography and Ecosystem analysis, accessibility, public transport accessibility levels, geographic accessibility
• publication/series: LUMA-GIS Thesis
• report number: 37
• language: English
• id: 4939051
• date added to LUP: 2015-01-22 13:17:43
• date last changed: 2015-01-22 13:17:43