Public transport accessibility level
The next stage is to determine the service level during the morning peak (defined as 0815–0915) for each route serving a SAP.
Large site developments (those the London boroughs refer to the Greater London Authority) must follow planning guidelines that allow more parking in areas with low PTALs (i.e., poor public transport) and vice versa—and that also relate the allowed density of development to PTAL (i.e., areas with better public transport may have higher density housing or offices).
However, in Ahmedabad, given the lack of availability of building footprint data at the time of the study, the method deviated by construing POIs as centroids of a 1 km2 grid.
The others adaptation of London method to Ahmedabad included revisiting walk speed and public transport service reliability assumptions.
The Surat study discussed several uses of PTAL mapping such as: [1] prioritising public transport investments [2] Integrating transport in development/master plan [3] informing the parking policy [4] improving residential location choice and optimizing the supply of affordable housing, and [5] understanding the mobility needs of the urban poor, which is based on another study in Ahmedabad.
[7] It argues that living in high PTAL areas may not necessarily translate to high accessibility to destination by public transport, especially those urban poor with variable job destination by month and season (e.g., construction workers, casual labourers, street vendors, etc.).
The maps of the baseline and the tentatively committed scenarios formed the basis for further research on its applications to improve the urban plan-making process.
The authors also proposed combining this tool to develop a holistic dashboard; this could be used by the stakeholders in making more informed decisions focused on land use transport integration.
This established the need to analyse the accessibility of the public transport network in relation to the planned future developments that builds on the analysis of the current situation.
The mapping provides a visual representation of the existing accessibility levels (see figure Hubli-Dharwad PTAL 2020 (base year) overlaid on 2011 Census population density) that can further be used to facilitate the decision-making process in master plan preparation and guide future public transport investments, rationalise land use distribution, help decide sites for affordable housing locations, and support the demarcation of transit-oriented development (TOD) zone demarcation.
In the study, the PTAL map was superimposed with the proposed Master Plan 2031, which envisions Hubli-Dharwad to grow as a compact and equitable city.
A key methodological step was to start with the base year PTAL map and overlay layers of existing land use, job density, development and demand potential, PT improvement leading to a robust public-transport centric development plan for 2031 (see figure Methodology to arrive at a robust PT-centric future plan (2031)).
Recommendations were made to improve public transport infrastructure to ensure synchronisation with the existing job centres and proposed development.
The PTAL map was also superimposed on proposed affordable housing locations in the Master Plan to assess accessibility to public transport, and hence, recommendations were made to improve connectivity to these zones.
It uses GIS to calculate door-to-door travel times by public transport to a grid of points around the point of interest, resulting in a set of isochrone maps – journey time contours – within which the number of workplaces, households or residents can be calculated using census data.
This method takes into account many more factors than PTAL, but is much more time-consuming and requires a level of expertise with GIS software and methodologies.
