The "Mellanby effect" in alcoholised e-scooter drivers.

Purpose: Several studies tried to discuss and clarify the so-called Mellanby effect: Similar blood alcohol concentrations (BACs) supposedly lead to more signs of impairment in the phase of alcohol resorption than elimination. To assess this effect for alcoholised e-scooter driving, results of a real-driving fitness study were subanalysed.

Methods: Sixteen subjects (9 females; 7 males) who completed runs at comparable BACs in the phases of alcohol resorption and elimination were chosen to assess a possible "Mellanby effect". The data of the subjects was taken from a prior e-scooter study by Zube et al., which included 63 subjects in total.

Results: In the phase of alcohol resorption, the relative driving performance was approx. 92% of the phase of elimination (p value 0.21). Statistically significant more demerits were allocated to the obstacle "narrowing track" in the phase of resorption than elimination. Subjects also needed significantly more time to pass the obstacles "narrowing track", "driving in circles counterclockwise" and "thresholds" in the phase of resorption than elimination.

Discussion: The most relevant obstacle to discriminate between the two different states of alcoholisation was the narrowing track. Insofar, measurements of the standard deviation of the lateral position (SDLP) might also be a sensitive component for the detection of central nervous driving impairment during shorter trips with an e-scooter. Additionally, driving slower during the phase of alcohol resorption seems to be the attempt to compensate alcohol-related deficits.

Conclusion: The results of the study suggest a slight Mellanby effect in e-scooter drivers.