Why are newly qualified motorists at high crash risk? Modelling driving behaviours across the first six months of driving.

Objective: Novice driver crash risk diminishes steeply over the first few months of driving. We explore the characteristics of driving over this period to identify behaviours that might underlie this change in risk.

Methods: We conducted a cross-sectional study of 1456 UK drivers aged 17-21 within six months of gaining their licence. We examined how various forms of driving exposure, such as weekly mileage and driving at night, were related to duration of licencing. We explored the factor structure of the Early Driving Development Questionnaire (EDD-Q); a new instrument designed to measure safety relevant attitudes and behaviours in recently qualified drivers. We examined the relationship of the derived factors to licence duration.

Results: There was little evidence that greater exposure to risky driving situations was more common in those with shorter licence durations. Exploratory and Confirmatory Factor Analyses identified EDD-Q factors measuring risky style (12 items), skill deficiencies (8 items) and driving confidence (4 items). Licence duration was positively correlated with both risky style and confidence, with these relationships stronger for older novices. Licence duration was also negatively related to skill deficiencies (i.e., positively correlated with perceived driving skill development): this relationship was stronger in younger novices.

Conclusions: The negative correlation between license duration and skill deficiencies is consistent with the observation of decreasing novice crash involvement as experience is gained. The EDD-Q offers a new brief measure of aberrant driving that is specifically tailored for newly qualified drivers.