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Billy Hwang, J.D.
Program Manager, Research Scientist
Billy is a Research Scientist and the Program Manger of TTI's Planning & Engagement Program. He has 18 years of experience providing policy, planning, and management support for local and state government agencies. Prior to joining TTI in 2020, Billy was a Principal Consultant at WSP, held staff and executive-level positions in local and state government agencies, and served in executive leadership at local and state transportation agencies. He also brings relevant skills as a licensed attorney, with experience in legislative and regulatory drafting, contracts and agreements, and negotiations. Read full resume.
Tina Geiselbrecht
Senior Research Scientist
Tina is certified as a Public Participation Professional (CP3) by the International Association for Public Participation and is a senior research scientist with the Planning and Engagement program at TTI. She is especially interested in the interaction between public engagement and policy development. Using qualitative and quantitative public opinion research, she supports agencies in conducting meaningful public engagement to facilitate transportation planning and policy decision-making. Tina has been the lead researcher on several projects at the local, state and national level that have explored public opinion through the use of surveys, stakeholder interviews and focus groups. She has facilitated over 150 focus groups for both internal and external audiences, and she has conducted more than 200 structured interviews with various elected officials, stakeholders, and special interest groups. Tina also explores the effectiveness of public involvement processes through systematic evaluation. She works to support agencies that strive to innovate in the engagement arena to develop and deliver transportation projects that are equitable, sustainable and reflective of community values. Her research has produced deliverables that help agencies engage the public in decision-making and help the public to understand their role in transportation and how changes in the system may impact their lives. Read full resume.
Joan Hudson, PE
Research Engineer
Joan has been involved with research activities at TTI since 2001, with a major area of emphasis on Bicycle, Pedestrian, and Transit Safety and Planning. Her main sponsors include TxDOT, Transit Cooperative Research Program, and the National Cooperative Highway Research Program. Joan has over 30 years of experience as a traffic engineer, 11 of those with the City of Austin's Transportation Division where she gained an understanding and appreciation for transportation-related quality of life at all stages of a person’s life. Read full resume.
Chris Simek, PMP
Research Scientist
Chris has 22 years of project management and travel behavior survey research experience, including 12 years in private sector consulting, and 10 years in university research. Throughout his career, his work and experience has been focused in the areas of travel surveys to support urban transportation models and urban planning policy. Since 2000, Chris has been involved in the management, design, and/or analysis of dozens of travel behavior surveys across the United States and Canada. Chris' professional interests include project management, public opinion research, travel behavior, survey and sample design, weighting and expansion, statistical analysis, and transportation public policy. Chris is a certified Project Management Professional (PMP). Read full resume.
Gretchen Stoeltje, J.D.
Associate Research Scientist
Gretchen is an Associate Research Scientist at TTI, where she focuses on communication and policy for existing and emerging transportation issues. Recent project topics have included emerging legislation for automated vehicles, regulation of transportation network companies, transportation funding, shared, app-based and integrated mobility options, online communities in use by governmental entities, and the implications for consent and privacy in the use of passively collected data for transportation research. Prior to joining TTI in March 2014, Gretchen worked as a policy researcher and communications specialist at the Texas Department of Transportation where she developed original research, internal and external media products, managed projects with policy consultants, and helped to facilitate the agency's strategic planning process. Before and throughout her time in state government, Gretchen has worked as an independent documentary filmmaker, producing, directing and distributing three titles of her own and collaborating on many others. Read full resume.
Olivia Wang
Assistant Research Scientist
Dr. Wang is an Assistant Research Scientist at TTI. Before joining TTI, she worked at UNC-Chapel Hill as a postdoctoral researcher on research projects of improving healthcare access for socially disadvantaged groups and using high-resolution data such as mobile device data to understand the travel behavior of different groups of people. She holds a Ph.D. in Public Affairs (Urban Transportation Planning Track) from the University of Minnesota and a Master of Urban Planning (Transportation Planning Track) from the University of Southern California. Her overall research goals are to understand the impacts of planning on travel behavior, human activities, well-being, and the corresponding equity implications of these impacts. Her research focuses on three major topics: 1) Active travel modeling and safety; 2) New transportation technologies and shared mobility; 3) Health outcomes resulting from daily travel and activities. Her research also examines equity issues around these topics. Over 10-year experience in transportation research, Dr. Wang has published over 25+ papers and technical reports in the relevant topics and developed solid skills in data collection, quantitative analysis, spatial modeling etc. Read full resume.
Billy Hwang, J.D.
Program Manager, Research Scientist
Tina Geiselbrecht
Senior Research Scientist
Joan Hudson, PE
Research Engineer
Chris Simek, PMP
Research Scientist
Gretchen Stoeltje, J.D.
Associate Research Scientist
