The "Mellanby effect" in alcoholised e-scooter drivers

Area of Science:

• Forensic Science
• Neuroscience
• Traffic Safety

Background:

• The Mellanby effect posits greater alcohol impairment during absorption than elimination at similar blood alcohol concentrations (BACs).
• Previous research has explored this effect in various contexts, but its specific impact on e-scooter driving remains under-investigated.

Purpose of the Study:

• To investigate the presence and magnitude of the Mellanby effect in alcohol-impaired e-scooter driving.
• To analyze driving performance differences between the alcohol absorption and elimination phases.

Main Methods:

• Subanalysis of data from a prior e-scooter driving fitness study involving 63 participants.
• Selection of 16 subjects (9 female, 7 male) with comparable BACs during both absorption and elimination phases.
• Assessment of driving performance metrics, including obstacle navigation and time taken.

Main Results:

• E-scooter driving performance was approximately 92% during alcohol absorption compared to elimination.
• Significantly more demerits were recorded for the 'narrowing track' obstacle during absorption.
• Increased time was required to navigate 'narrowing track', 'driving in circles counterclockwise', and 'thresholds' obstacles during absorption.

Conclusions:

• The 'narrowing track' obstacle effectively differentiated driving impairment levels between absorption and elimination phases.
• Standard deviation of the lateral position (SDLP) may serve as a sensitive indicator of driving impairment during short e-scooter trips.
• Slower driving speeds during alcohol absorption appear to be a compensatory strategy for alcohol-related deficits.