OLDER DRIVERS with Type 2 diabetes took longer to brake in a driving simulator than those without diabetes, regardless of whether they had diabetic peripheral neuropathy, a study has found.
The research also identified associations between braking time, female sex, and reduced plantar flexor muscle strength, highlighting the potential importance of lower-limb function when assessing driving performance in older adults.
The cross-sectional study compared three groups of drivers aged 60–79 years: 17 with Type 2 diabetes without peripheral neuropathy, 22 with diabetes and neuropathy, and 25 controls without diabetes. Participants in the diabetes groups had been diagnosed for more than 5 years.
Researchers assessed peripheral neuropathy using the Brazilian version of the Michigan Neuropathy Screening Instrument. Participants also underwent tests of cognition, vision, functional mobility, handgrip strength, and plantar flexor strength, which measures the muscles involved in pointing the foot downwards.
Driving performance was evaluated using a simulator equipped with vehicle controls and three screens. Following a familiarisation drive, participants completed a simulated highway route where a “stop” command appeared randomly five times. Researchers calculated average braking response time across these trials.
Average braking time was 0.97 seconds among participants with diabetes without neuropathy and 1.00 second among those with neuropathy, compared with 0.86 seconds in the control group. Both diabetes groups had significantly longer braking times than controls.
The difference between participants with and without neuropathy was not statistically significant. This suggests that, within this sample, slower braking responses were associated with diabetes even in the absence of identified peripheral neuropathy.
Participants with neuropathy also had lower dominant-hand grip strength and reduced right plantar flexor strength compared with controls. However, the reported cognitive, visual, and mobility assessments did not identify significant differences between groups.
After adjustment for age, sex, and the plantar flexor strength measure, both diabetes groups continued to show longer braking times than controls. Female sex and lower plantar flexor strength were associated with slower responses. Age did not reach statistical significance in the adjusted model.
The authors suggest that assessing lower-limb strength could help identify functional difficulties and guide targeted resistance exercise or sensorimotor training. However, the study did not test whether these interventions improve braking performance or reduce collisions.
The findings require cautious interpretation. The sample was small, participants were recruited through convenience sampling, and sex distribution differed across groups. Simulator testing also cannot fully reproduce the demands of real-world traffic.
As a cross-sectional study, the research cannot establish causation or determine actual collision risk. Larger longitudinal studies are needed to clarify these associations and assess whether interventions can support driving safety while preserving independence.
de Matos Souza V. R. et al. Braking Time and Cognitive, Visual, and Motor Determinants in Older Drivers With Type 2 Diabetes Mellitus With and Without Diabetic Peripheral Neuropathy: A Controlled Cross-Sectional Study, Journal of Diabetes 18, no. 10 (2026): e70269
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