About

Gulsah Akar is the Professor and Chair of the School of City and Regional Planning at Georgia Tech. Her research focuses on sustainable urban mobility, examining the built environment and travel connections using advanced data collection technologies, measuring access and equity, analyzing demographic and socioeconomic differences in transportation outcomes, and studying the adoption of emerging mobility technologies. Her work aims to contribute to creating sustainable and resilient communities through improved urban mobility systems. Professor Akar joined Georgia Tech in 2021, having previously served as a professor at The Ohio State University, where she led the PhD Program and was a Research Program Lead at the Sustainability Institute. She has served as the Editor of the Journal of Planning Literature and is actively involved in transportation research committees. Her academic background includes a Ph.D. from the University of Maryland and both B.Sc. and M.Sc. degrees from Middle East Technical University in Turkey. Her teaching interests include transportation planning, research methods, and quantitative analysis, with a focus on applying analytical tools to understand travel behavior and urban mobility outcomes.

Research topics

• Sociology
• Business
• Transport engineering
• Geography
• Engineering
• Environmental health
• Medicine
• Psychology
• Demography
• Computer Science
• Economics
• Econometrics
• Mathematics
• Marketing
• Advertising
• Statistics

Selected publications

• Linking built environments and pre-crash pedestrian behaviors: A Safe Systems approach to crash severity

  Figshare · 2026-03-10

  articleOpen accessSenior author

  Pedestrians are the most vulnerable road users, and the number of crashes has increased in the past decade. Within the Safe Systems framework that recently gained attention, crashes result from the interaction between environmental factors and the parties involved, and pedestrian safety can be improved by creating more supportive environments. Previous studies have examined the influence of built environment and other risk factors on crash severity, yet little is known about how their protective effects differ across pre-crash pedestrian behaviors. Using pedestrian–vehicle crashes in Georgia from 2013–2022 (<i>N</i> = 17,233), our analysis contributes to this literature by discerning the role of built environment across different situational contexts, categorized by three pedestrian behaviors at the time of crash: crossing at crosswalk, crossing not at crosswalk, and walking along traffic. Multinomial logit models are separately estimated for each case. Across all crashes, those involving pedestrians aged over 65 years, large vehicles, unlit road conditions, and high speed limits are more likely to result in severe pedestrian injuries. Behavior-specific models show that even when pedestrians are crossing mid-block, higher pedestrian-oriented network density mitigates injury severity. Additionally, crashes are more likely to be severe in areas with dense auto-oriented links, particularly when pedestrians are walking along the traffic, often due to lack of supportive infrastructures. Lastly, where pedestrians are at crosswalks, drivers aged 20–24 years are associated with a higher likelihood of serious pedestrian injuries. These findings highlight the heterogeneous role of built environments in shaping crash outcomes depending on contexts. The patterns align with the Safe Systems framework such that insufficient built environments elevate injury severity, while pedestrian-oriented infrastructures can mitigate harm even when behaviors are less predictable. Thus, infrastructure improvements should be recognized as behavioral interventions and injury prevention strategies that absorb human errors, not simply as street environment upgrades.

  PublisherDOI

• Linking built environments and pre-crash pedestrian behaviors: A Safe Systems approach to crash severity

  Traffic Injury Prevention · 2026-03-10 · 3 citations

  articleSenior author

  OBJECTIVE: Pedestrians are the most vulnerable road users, and the number of crashes has increased in the past decade. Within the Safe Systems framework that recently gained attention, crashes result from the interaction between environmental factors and the parties involved, and pedestrian safety can be improved by creating more supportive environments. Previous studies have examined the influence of built environment and other risk factors on crash severity, yet little is known about how their protective effects differ across pre-crash pedestrian behaviors. METHODS: = 17,233), our analysis contributes to this literature by discerning the role of built environment across different situational contexts, categorized by three pedestrian behaviors at the time of crash: crossing at crosswalk, crossing not at crosswalk, and walking along traffic. Multinomial logit models are separately estimated for each case. RESULTS: Across all crashes, those involving pedestrians aged over 65 years, large vehicles, unlit road conditions, and high speed limits are more likely to result in severe pedestrian injuries. Behavior-specific models show that even when pedestrians are crossing mid-block, higher pedestrian-oriented network density mitigates injury severity. Additionally, crashes are more likely to be severe in areas with dense auto-oriented links, particularly when pedestrians are walking along the traffic, often due to lack of supportive infrastructures. Lastly, where pedestrians are at crosswalks, drivers aged 20-24 years are associated with a higher likelihood of serious pedestrian injuries. CONCLUSIONS: These findings highlight the heterogeneous role of built environments in shaping crash outcomes depending on contexts. The patterns align with the Safe Systems framework such that insufficient built environments elevate injury severity, while pedestrian-oriented infrastructures can mitigate harm even when behaviors are less predictable. Thus, infrastructure improvements should be recognized as behavioral interventions and injury prevention strategies that absorb human errors, not simply as street environment upgrades.

  PublisherDOI

• Linking built environments and pre-crash pedestrian behaviors: A Safe Systems approach to crash severity

  Open MIND · 2026-03-10

  articleSenior author

  Pedestrians are the most vulnerable road users, and the number of crashes has increased in the past decade. Within the Safe Systems framework that recently gained attention, crashes result from the interaction between environmental factors and the parties involved, and pedestrian safety can be improved by creating more supportive environments. Previous studies have examined the influence of built environment and other risk factors on crash severity, yet little is known about how their protective effects differ across pre-crash pedestrian behaviors. Using pedestrian–vehicle crashes in Georgia from 2013–2022 (<i>N</i> = 17,233), our analysis contributes to this literature by discerning the role of built environment across different situational contexts, categorized by three pedestrian behaviors at the time of crash: crossing at crosswalk, crossing not at crosswalk, and walking along traffic. Multinomial logit models are separately estimated for each case. Across all crashes, those involving pedestrians aged over 65 years, large vehicles, unlit road conditions, and high speed limits are more likely to result in severe pedestrian injuries. Behavior-specific models show that even when pedestrians are crossing mid-block, higher pedestrian-oriented network density mitigates injury severity. Additionally, crashes are more likely to be severe in areas with dense auto-oriented links, particularly when pedestrians are walking along the traffic, often due to lack of supportive infrastructures. Lastly, where pedestrians are at crosswalks, drivers aged 20–24 years are associated with a higher likelihood of serious pedestrian injuries. These findings highlight the heterogeneous role of built environments in shaping crash outcomes depending on contexts. The patterns align with the Safe Systems framework such that insufficient built environments elevate injury severity, while pedestrian-oriented infrastructures can mitigate harm even when behaviors are less predictable. Thus, infrastructure improvements should be recognized as behavioral interventions and injury prevention strategies that absorb human errors, not simply as street environment upgrades.

  DOI

• Heat Sensitivity and Travel Mode in Streetscape Preferences for Thermal Comfort

  SSRN Electronic Journal · 2026-01-01

  preprintOpen accessSenior author
  PublisherDOI

• Comparing younger and older bike share users’ route choice: the role of streetscape and midblock conflicts

  Travel Behaviour and Society · 2026-05-01

  articleOpen accessSenior author
  PublisherDOI

• Understanding rail users' mode choice behavior for first and last mile travel

  Journal of Transport Geography · 2025-04-04 · 4 citations

  articleSenior author
  PublisherDOI

• Is the Environmental Kuznets Curve Still Relevant in the Modern Context? – Insights From Air Pollutants in Chinese Cities

  Managing Global Transitions · 2025-09-30

  articleOpen accessSenior author

  This study investigated the presence of EKC-like relationships between various socioeconomic variables and air pollution indicators across 151 Chinese cities, analysed by quadratic regression models and geographic weighted regression (GWR) analysis. The results present critical insights into the applicability and limitations of the EKC. Only Air Quality Index, Nitrogen Dioxide (NO2), and Fine Particulate Matter (PM2.5) show statistically significant correlations with one socioeconomic variable, respectively, in an EKC-like pattern which is meaningful in reality. GWR coefficients serve as a diagnostic tool to identify those burdened cities where stricter emissions standards, greener industrial practices, or economic restructuring should be prioritized. The spatial dependencies challengethe EKC’s assumption of isolated environmental-economic dynamics. Stricter environmental regulations in developed areas often lead to the displacement of polluting activities to regions with laxer standards. Policy efforts in tackling air pollution should focus on directly reducing emissions through localized, technology-based interventions rather than relying on economic growth to eventually improve air quality. Spatially targeted policies informed by city-specific patterns are essential, as pollution outcomes are shaped by regional industrial structures, population density, and cross-boundary spillover effects.

  PublisherOA PDFDOI

• Examining associations between individual and built environment characteristics and walking trip bouts: Evidence from the 2017 California household travel survey

  Transportation Research Interdisciplinary Perspectives · 2025-04-15 · 3 citations

  articleOpen accessSenior author

  • Factors known to increase walking counts had different associations with short- and long-bout walking trips. • Merely increasing the total number of walking trips may not necessarily lead to improved health outcomes. • Gender, race, employment, medical conditions, and physical activity levels were associated with walking bout durations. • Pedestrian links and employment diversity were particularly influential in increasing long-bout walking trips. • Promoting public health through walking requires understanding the interplay between walking predictors, bout duration, and health. Walking is an affordable physical activity that promotes various health outcomes. Studies focusing solely on walking frequency may not fully capture its health benefits, as duration is more closely linked to significant benefits. Considering both walking frequency and bout duration can provide insights into walking behavior and its health benefits. This study aims to examine how individual and built environment characteristics relate to short- and long-bout walking trips, using data from the 2017 California Household Travel Survey and the Smart Location Database 3.0. Our analysis involved multilevel mixed-effects negative binomial regression with a sample of 32,178 individuals aged 18 and over. Results revealed that individual, socioeconomic, and built environment characteristics are differently associated with short- and long-bout walking trips, potentially leading to different health benefits from the same number of walking trips. Individuals who rarely engaged in physical activity or had medical conditions were less likely to engage in long-bout walking trips. Built environment densities had similar effects on both walking trip types, while employment diversity was associated only with long-bout walking trips. Notably, the effects of pedestrian link density were more pronounced on long-bout walking trips. Predicted long-bout walking trip counts were not associated with urbanicity, while short-bout walking trip counts were higher in urban areas than in suburban areas. Therefore, promoting public health through walking requires a comprehensive approach that considers socio-economic and built environment factors, acknowledging the varying health effects of walking based on bout duration.

  PublisherDOI

• Je okoljska Kuznetsova krivulja še aktualna v današnjem času?

  Repository of the University of Primorsk (University of Primorska) · 2025-09-30

  articleSenior author

  This study investigated the presence of EKC-like relationships between various socioeconomic variables and air pollution indicators across 151 Chinese cities, analysed by quadratic regression models and geographic weighted regression (GWR) analysis. The results present critical insights into the applicability and limitations of the EKC. Only Air Quality Index, Nitrogen Dioxide (NO2), and Fine Particulate Matter (PM2.5) show statistically significant correlations with one socioeconomic variable, respectively, in an EKC-like pattern which is meaningful in reality. GWR coefficients serve as a diagnostic tool to identify those burdened cities where stricter emissions standards, greener industrial practices, or economic restructuring should be prioritized. The spatial dependencies challengethe EKC’s assumption of isolated environmental-economic dynamics. Stricter environmental regulations in developed areas often lead to the displacement of polluting activities to regions with laxer standards. Policy efforts in tackling air pollution should focus on directly reducing emissions through localized, technology-based interventions rather than relying on economic growth to eventually improve air quality. Spatially targeted policies informed by city-specific patterns are essential, as pollution outcomes are shaped by regional industrial structures, population density, and cross-boundary spillover effects.

  Publisher

• Influence of neighborhood walkability on older adults’ walking trips: Does income matter?

  Travel Behaviour and Society · 2024-09-24 · 1 citations

  articleSenior author
  PublisherDOI

Frequent coauthors

• Kailai Wang

  12 shared

• Kelly J. Clifton

  West Los Angeles College

  10 shared

• Basar Ozbilen

  6 shared

• Mi Namgung

  Pusan National University

  6 shared

• Sean Doherty

  Wilfrid Laurier University

  5 shared

• Steven I. Gordon

  The Ohio State University

  5 shared

• Yu-Jen Chen

  Fu Jen Catholic University

  4 shared

• Na Chen

  Sun Yat-sen University

  4 shared