Exploring Biological Markers of Driver Fatigue for Enhanced Road Safety

Recruiting

• Conditions: Drowsiness; Sleepiness; Fatigue

• Registration Number: NCT07089342
• Lead Sponsor: University of Zurich

Brief Summary

The aim of this study is to assess the effectiveness of biological markers in detecting fatigue/sleepiness in a sample of the general driving population in Belgium. The link between the collected biomarkers (oral fluid sample), observed signs of sleepiness in the driver and self-reported driver variables will be analysed. The analysis of the biological samples aims to measure endogenous metabolite levels that are possibly indicative for sleepiness of the donor driver. The respective metabolites will be chosen based on the results of a preceding clinical study (https://clinicaltrials.gov/study/NCT05585515). The objective of this study is to verify and validate the proposed metabolites as biomarkers for driver sleepiness in road traffic.

Detailed Description

Researchers from NICC (National Institute of Criminalistics and Criminology) and VIAS will collect (1) saliva samples (Salivette with neutral swab allowing use by not-medically trained personnel; this sampling method is also used by the Belgian police in scope of the drugs in traffic legislation since 2019), (2) self-reported driver data (survey) and (3) observed driver data (form filled in by researchers) from drivers that were stopped on the road in scope of routine police checks. The collaboration with the police is because police can stop drivers randomly on-road while researchers cannot. After the police check, a researcher will ask if the driver wants to participate in a study on driver fatigue which is entirely independent from the police check. Voluntary drivers sign an informed consent form.

The collected saliva samples will be entirely separate from any sample obtained during the police checks. During data collection, the saliva sample, driver survey and observation form will each get a unique identification code to link the data. Afterwards, the researchers will work with this anonymised number and the data cannot be traced back to the participant.

All anonymised samples/data will temporarily be stored at NICC (Dept. Toxicology) and then be sent to the University of Zurich for analysis. The analysis of the saliva samples aims to measure endogenous metabolite levels that are possibly indicative for sleepiness of the donor. The correlation of the biomarker levels with observed/reported driver data will be measured. In specific cases the co-existence of drugs/medication in the saliva samples may also be tested: when the donor reported the consumption of the respective substance in the driver survey, as a confirmatory analysis, and (2) when the researchers believe the co-consumption of drugs/medication may interfere with the primary analysis. All anonymised samples will be stored at the University of Zurich for a maximum of 10 years and then be destroyed.

Study Timeline

• Status Verified: 2025-07
• Study Start: 2025-07-01
• Study First Submitted: 2025-07-09
• Study First Submitted QC: 2025-07-20
• Last Update Submitted: 2025-07-20
• Study First Posted: 2025-07-28
• Last Update Posted: 2025-07-28
• Primary Completion: 2025-12
• Study Completion: 2025-12-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 500

Inclusion Criteria

• drivers randomly stopped by the police

Exclusion Criteria

• refusal to sign informed consent

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Changes in metabolite concentrations in oral fluid quantified by liquid chromatography with mass spectrometry	Baseline: One collection time point after enrollment	Investigators will collect oral fluid samples for quantification of all detectable metabolites. Investigators will analyze which metabolite concentration values undergo significant changes with regard to sleep/wake history and demographical data of the donor.

Secondary Outcome Measures

Name	Time	Method
Subjective sleepiness	Baseline: One time point after enrollment	Participants will complete the Karolinska Sleepiness Scale (version A) questionnaire. It is a 9-point scale, ranging from 1 (extremely alert) to 9 (very sleepy, great effort to keep awake, fighting sleep).
Behavioral markers of drowsy driving: Shivering	Baseline: One time point after enrollment	Investigators will examine participants for behavioral abnormalities concerning shivering based on this scale: (i) yes (ii) no (iii) uncertain
Behavioral markers of drowsy driving: Reaction	Baseline: One time point after enrollment	Investigators will examine participants for behavioral abnormalities concerning reaction based on this scale: (i) slow/tired (ii) normal (iii) fast/talkative
Behavioral markers of drowsy driving: Gait	Baseline: One time point after enrollment	Investigators will examine participants for behavioral abnormalities concerning gait based on this scale: (i) slow (ii) normal (iii) uncertain

Trial Locations

Locations (1)

Vias institute; 🇧🇪 Brussels, Belgium