Current projects
A feasibility study of the effects of cognitive training on neurocognition and driving performance among older adults
This PhD pilot study will test the feasibility and potential effectiveness of a 6-week cognitive training program in improving attention (as assessed through EEG changes) and simulated driving performance in healthy older adults.
Ageing road users
This project seeks to leverage findings from the Ageing Driver Typologies project to understand how ageing road users adapt their behaviour to their local environment (bottom-up) and what support or existing practices may inform locally relevant, safe mobility initiatives (top-down). This project will inform a potential road safety, place-centric pilot program that focuses on supporting the safe mobility of ageing road users.
Driving patterns across the ages
This project aims to investigate how driving behaviours and subjective cognitive capabilities change across the lifespan.
Examining the effects of cardiovascular disease risk factors on cognition and driving performance among older adults
This project will use existing de-identified data among older adults (from the ROADSAFE Study) to examine the relationship between cardiovascular disease risk factors, cognition, and driving.
Exploring EEG-based neural correlates of driving ability in older adults
This PhD program of work will investigate the relationship between neurocognitive functioning (as assessed through EEG measures) and driving performance in healthy older adults. There is currently one publication associated with this project.
Publication:
Ellis, S., Summers, M. J., Clark, M., & Stefanidis, K. B. (2026). The relationship between electroencephalographic measures and driving performance in older adults: A scoping review. Journal of Transport & Health, 48, Article 102247. https://doi.org/10.1016/j.jth.2025.102247
Investigating the effects of medicinal cannabis flower on neurocognitive functions relevant for driving
This PhD program of work will identify neurocognitive changes in response to medicinal cannabis flower consumption at acute (<1 hour) and delayed stages (>2 hour), and whether these changes correlate with reductions in a measure of driving performance. There is currently one publication associated with this project.
Publication:
Schiemer, C., Summers, M. J., & Stefanidis, K. B. (2025). Identifying EEG markers related to acute cannabis consumption: A systematic review. Neuroscience & Biobehavioral Reviews, 172, Article 106092. https://doi.org/10.1016/j.neubiorev.2025.106092
Medcan Bio project
The project will investigate the trajectory of THC concentrations in oral fluid samples among tolerant and non-tolerant medicinal cannabis patients who have been prescribed oral (i.e., oils) or vaporised (i.e., flower) cannabis, over a 24-hour period.
Understanding the relationship between sleep, cognitive function and driving in healthy ageing
This project aims to explore the relationship between subjective and objective sleep, cognitive function and driving in older adults.
Completed projects
2026
Ageing driver typologies: A transition through time
This project aimed to explore older drivers’ (aged 60+ years) perceptions and understanding of safe driving practices as they age, as well as the factors that impact safe driving decisions in order to identify unique ageing driver groups to support tailored interventions and education.
This project is complete and the manuscript is currently being drafted for submission.
Cognitive function, sleep, and driving behaviour in older adults: A qualitative investigation
This research project explored the role of sleep in influencing cognitive function and driving ability / behaviour in older adults.
This project is complete and the manuscript is currently being drafted for submission.
Examining the efficacy of cognitive training programs for older drivers: A systematic review
This project is a necessary component of our program of work aiming to develop a cognitive training program for older drivers. This project helped determine the current state of knowledge concerning cognitive training programs for driving, and potential gaps in the literature.
This project is complete and the manuscript is currently being drafted for submission.
Exploring the feasibility of a cognitive training program for older drivers
This project explored older adults’ and health practitioners’ perspectives on cognitive training programs for older drivers, and aimed to identify factors that increase older adults’ willingness to engage in a cognitive training program for driving.
This project is complete. There are three manuscripts associated with this project. Two are currently under review, and the third is currently being drafted for submission.
Health practitioners' perspectives on fitness to drive assessments in older adults with cognitive decline / dementia
This project explored health practitioners’ perspectives and opinions regarding the assessment of fitness to drive in patients with cognitive decline/dementia.
This project is complete and the manuscript is currently being drafted for submission.
Medcan dose-controlled study
This project examined the effects of varying doses of THC on cognition and driving performance in medicinal cannabis users.
Publication:
Stefanidis, K. B., Larue, G. S., Summers, M. J., Horswill, M. S., Hill, A., & Armstrong, K. A. (2026). Identifying driving-related cognitive measures sensitive to varying doses of vaporised cannabis flower. Transportation Research Part F: Traffic Psychology and Behaviour, 122, Article 103777. https://doi.org/10.1016/j.trf.2026.103777
Medicinal cannabis, cognitive function, and hazard perception: The effects of orally ingested THC on cognitive function and hazard perception
The aims of this project included: (a) to investigate the effects of orally ingested THC on cognitive function and hazard perception and (b) to identify which cognitive measures most strongly correlate with changes in hazard perception performance following consumption of THC.
Publication:
Mieran, T., Hill, A., Horswill, M. S., Summers, M. J., & Stefanidis, K. B. (2026). The effects of orally ingested Delta-9-Tetrahydrocannabinol on drivers' hazard perception and risk-taking behaviours: A within-subjects study of medicinal cannabis users. Psychopharmacology, 243(3), 651–670. https://doi.org/10.1007/s00213-025-06869-w
Medicinal cannabis use and driving behaviours in older adults
This project explored medicinal cannabis use in older drivers, with the overall aim of examining relationships between medication use, perceived cognitive changes, and driving ability/safety behaviours in this cohort.
Publication:
Stefanidis, K. B., Schiemer, C., & Armstrong, K. (2026). Cannabis, self-ratings of cognition and driving behaviour among older adults: an exploratory study. Transportation Research Part F: Traffic Psychology and Behaviour, 122, Article 103733. https://doi.org/10.1016/j.trf.2026.103733
Neuropsychological correlates of fitness to drive in older adults (ROADSAFE Study)
This study aimed to examine a combination of cognitive performance measures that best predict driving capacity in older adults.
Publication:
Stefanidis, K.B., Larue, G., Horswill, M., Hill, A., & Summers, M.J. (2026). Identifying neuropsychological correlates of driving performance in older adults: Findings from the ROADSAFE Study. Transportation Research Part F: Traffic Psychology and Behaviour, 121, Article 103723. https://doi.org/10.1016/j.trf.2026.103723
The effects of cardiovascular disease on cognition and driving performance
This project examined the effects of cardiovascular disease (e.g., heart attack, heart disease) on cognitive functions relevant for driving, as well as driving simulator performance. Participants' performance was compared to that of a healthy control group matched for age and gender from the ROADSAFE study.
This project is complete and the manuscript is currently being drafted for submission.
2025
Assessing driving capacity in older adults: A general practitioner’s perspective
This project examined general practioners’ perceptions, opinions, and experiences regarding the assessment of older drivers, with a particular emphasis on cognitive assessments.
Publication:
Stefanidis, K. B., Summers, M. J., & Clark, M. (2025). The assessment of cognitive function and medical fitness to drive in older adults: A qualitative study with general practitioners. Journal of Transport and Health, 42, 1-8. https://doi.org/10.1016/j.jth.2025.102020
Assessing driving capacity in older adults: The perspective of older drivers
This project examined older adults’ perceptions and opinions relating to driving/fitness to drive assessments and the possibility of losing their licence.
Publication:
Stefanidis, K. B., Mieran, T., & Summers, M. J. (2025). Older adults' perspectives on annual medical assessments for driving: A qualitative investigation. Journal of Transport & Health, 42, Article 102047. https://doi.org/10.1016/j.jth.2025.102047
Neuropsychological markers of driving capacity in older adults with mild cognitive impairment and dementia: A meta-analysis
This project examined the relationship between neuropsychological test measures and driving capacity in patients with mild cognitive impairments/dementia.
Publication:
Stefanidis, K. B., Mieran, T., & Summers, M. J. (2025). Standardised neuropsychological test correlates of driving performance in mild cognitive impairment and dementia: A systematic review and meta-analysis. Journal of Transport & Health, 44, 1-14. https://doi.org/10.1016/j.jth.2025.102141
Vaping cannabis and its impact on cognitive function related to driving
The project investigated whether video-based driving tests (including the hazard perception test) and cognitive performance measures are sensitive to vaporised THC flower.
Publication:
Stefanidis, K. B., Schiemer, C., Mieran, T., Hill, A., Horswill, M. S., & Summers, M. J. (2025). Elucidating the acute effects of medically prescribed oral and vaporised delta-9-tetrahydrocannabinol on cognitive functions important for driving. Drug and Alcohol Review, 44(4), 1010–1023. https://doi.org/10.1111/dar.14060
2024
Systematic review examining the relationship between cognitive performance and driving impairment measures and driving capacity in older drivers
This review aimed to identify the cognitive measures that most strongly correlate with driving capacity and driving impairment in older drivers.
Publication:
Stefanidis, K. B., Mieran, T., Schiemer, C., Freeman, J., Truelove, V., & Summers, M. J. (2024). Cognitive correlates of reduced driving performance in healthy older adults: A meta-analytic review. Accident Analysis and Prevention, 193, Article 107337. https://doi.org/10.1016/j.aap.2023.107337
Systematic review looking at neurocognitive markers of THC
This review paper examined the sensitivity of neuropsychological and EEG measures in identifying THC.
Publication:
Stefanidis, K. B., Schiemer, C., Mieran, T., & Summers, M. J. (2024). Identifying standardised neuropsychological test measures sensitive to cannabis consumption: A systematic review. Journal of Affective Disorders, 369, 772-781. https://doi.org/10.1016/j.jad.2024.10.051