Pragun Vinayak Wins Pikarsky Award for Thesis
Pragun with MS advisor Chandra Bhat
At TRB this year, CTR grad student Pragun Vinayak received the Milton Pikarsky Memorial Award in transportation science and technology from the Council of University Transportation Centers (CUTC). This award recognizes Pragun’s outstanding MS thesis, “Accounting for Multi-Dimensional Dependencies Among Decision-makers within a Generalized Model Framework: An Application to Understanding Shared Mobility Service Usage Levels.” This thesis grew out of Pragun’s work on TxDOT project 0-6877, Communications and Radar-Supported Transportation Operations and Planning (CAR-STOP), which made use of matching funds from D-STOP, one of CTR’s UTC programs. Following is the thesis abstract.
Activity-travel choices of decision makers are influenced by spatial dependency effects. As decision-makers interact and exchange information with, or observe the behaviors of, those in close proximity to themselves, they are likely to shape their behavioral choices accordingly. For this reason, econometric choice models that account for spatial dependency effects have been developed and applied in a number of fields, including transportation. However, spatial dependence models to date have largely defined the strength of association across behavioral units based on spatial or geographic proximity. In the current context of social media platforms and ubiquitous internet and mobile connectivity, the strength of associations among decision-makers is no longer solely dependent on spatial proximity. Rather, the strength of associations among decision-makers may be based on shared attitudes and preferences as well. In other words, behavioral choice models may benefit from defining dependency effects based on attitudinal constructs in addition to geographical constructs. In this thesis, the frequency of usage of car-sharing and ride-sourcing services, collectively termed shared mobility services, is modeled using a sequential generalized heterogeneous data model: a spatial ordered response probit (GHDM – SORP) framework that incorporates multi-dimensional dependencies among decision-makers.
The model system is estimated on the 2014–2015 Puget Sound Regional Travel Study survey sample, with inter-dependence in attitudinal space defined using latent psychometric constructs reflecting inherent attitudes, lifestyle preferences, and habits. These latent constructs are based on variables in the data set that represent observed travel and locational choice behavior, as well as responses to attitudinal questions. Model estimation results show that social dependency effects arising from similarities in attitudes and preferences are significant in explaining shared mobility service usage, over and above what is explained by spatial dependency. Ignoring such effects may lead to erroneous estimates of the adoption and usage of future transportation technologies and mobility services.
Pragun’s win continues a streak of sorts: our transportation program has received the lion’s share of these national-level student thesis/dissertation awards over the last two decades. For seventeen years since 2000 (and with the exception of 2014), UT Austin transportation graduate students have been awarded at least one of the four annual Milton Pikarsky or Charley V. Wootan Awards for the best MS thesis/PhD dissertations in North America, making UT, by far, the #1 university in terms of the number of transportation graduate students from a single program to receive CUTC thesis/dissertation awards.