Review and evaluation of traffic impact assessment (TIA) study of the transit oriented development (TOD) influence zone plan
Geetam Tiwari and Kalaga Ramchandra Rao
Executive summary
Land use policy decisions can have an important influence on travel decisions of the inhabitants of an urban settlement. It is believed that an appropriate mix of landuses can cause reduction in personal vehicular travel and induce demand for public transit and non-motorized modes. This study explores the impact of landuse mix on travel behaviour patterns in context of Delhi.
Metro rail system was introduced in Delhi in 2002. With three phases completed and having 160 operational stations and network length of more than 200 km, Delhi government has notified a Transit Oriented Development (TOD) policy for influence zones along metro rail corridor for the city of Delhi (TOD Policy, 2015). The policy calls for a Traffic Impact Assessment study to provide inputs for optimizing mix of land use and population/employment density in the influence zone.
Part I of this study is in continuation to the TIA study (2014) which looks into the impact of land use and density patterns on vehicular trip generation and mode choice. Though largely neglected in the TIA study (2014), it is equally important to study the impact of land use pattern at the destination end of a trip. Current study explores this aspect of relationship between land use/density pattern and the trips attracted by a zone. The primary research question that this study attempts to answer is how effectively we can use land use pattern and demographic characteristics to predict trip attractions. The main objective is to formulate a ‘Trip Attraction’ model for Delhi based on analysis of ‘Land use pattern’ and ‘Population/Employment distribution’. To maintain transferability of datasets this study uses same Travel Analysis Zones (TAZs) in Delhi as used in the TIA study (2014). All the necessary data including land use, population, employment was compiled for each zone.
The resulting outcome of the analysis is a model to predict trip attraction for an area. Regression analysis has been used to estimate the zonal trip attraction models. The analysis uses multiple variables and indicators of development density (population and employment), mixed use (land use entropy, dissimilarity and proportions) and accessibility (transit stop density, intersection density and distance to metro and city centre). The study explains how the land use information can be substantiated with relevant demographic information for achieving more accurate results. It establishes the relationship between development pattern and travel demand for the study area.
Part II of this study examines the data maintenance practices for city bus systems in Indian cities. This study also provides review of the international practices and evaluates their applicability to Indian context. We primarily explore the data formats developed by the Association of State Road Transport Undertakings (ASRTU), which maintains the data for all government bus operators in the country. Based on the existing practices and review of international best practices, a pathway for improved data collection and analysis is developed and suggested. The main objective of the study is to review the data maintenance practices of ASRTU and prepare a roadmap for improvements in the future based on international best practices. The study explores the gaps by comparing Indian and International literature in data maintenance and performance measurement in bus based public transport systems. Finally, suggestions and recommendations are made for improvements at the stages of Data Collection, Data Reporting and Performance Measurement System.
1.1 Activities
Primary activities undertaken during the course of study are as follows:
Data Collection and surveys
Section 5 of the study (Part - I) provides details on data collection and surveys undertaken during the course of study.
1.2 Outcomes
Study Part- I
Outcome of this study is in the form of a ‘Trip attraction tool’ as described in the section 7 of the report (Part-I).
Study part- II
Outcome of this study are in terms of policy implications, suggestions and recommendations as described in section 6 of the report (Part-II)
1.3 Way Forward
The TIA study (2014) on TOD impact assessment and this study on ‘Trip attraction tools’ collectively present a methodology to assess the impact of land use mix in an influence zone on travel demand. Still, it was felt that we need to clearly assess the definition and extent of influence zone. As discussed earlier, its definition and extent has been repeatedly revised in absence of evidence as to what distance can be considered walking distance in our context. Further, in order to meticulously study ridership impacts of land use around metro stations, we need to look at the ‘diurnal’ ridership pattern of each metro station on the metro rail network and study it in relation to land uses around each category of metro station (based on zonal land use). Our suspicion is that cumulative daily ridership of a metro station has limited capability to explain impact of different categories of land use. Diurnal boarding and alighting pattern for metro stations in residential, commercial, office areas etc. may be significantly different for all such categories. This study would further contribute to evidence based understanding of metro ridership patterns.