The impact of periodic heavy vehicle inspection on vehicle defects: Evidence from periodic and roadside inspections in Queensland

Heavy vehicle crashes are associated with significant economic and social costs. In a twelve months period ending June 2015, heavy vehicles were involved in 182 fatal crashes with 213 deaths in Australia (BITRE, 2015). The crash fatalities of the Australian freight industry constitutes almost one third of all work-related crash fatalities (Raftery, Grigo, & Woolley, 2011). Representing only 3% of the total number of registered vehicles and 8% of the total vehicle kilometres travelled, heavy vehicles are involved in 18% of fatal and serious injury crashes (Mooren, Grzebieta, Williamson, Olivier, & Friswell, 2014). Although most crashes are considered to be related to driver errors, the impact of vehicle defects is evident in many crashes (Blower, Green, & Matteson, 2010). Hence, different vehicle inspection schemes, including Queensland’s certificate of inspection (COI) scheme, have been implemented around the world to more effectively manage the safety of heavy vehicles (Keall & Newstead, 2013). The COI scheme enforces any heavy vehicle registered in Queensland to undergo a periodic inspection every 6 or 12 months, depending on the vehicle’s type. However, there is little empirical research about the impact of periodic heavy vehicle inspections on vehicle defects, number of crashes and crash casualties (Mooren et al., 2014). Accordingly, this research aims at investigating the effectiveness of periodic heavy vehicle inspections, specifically by examining the impact of the COI scheme on heavy vehicle defects in Queensland. To address this objective, the current study seeks to evaluate potential differences between the results of random roadside inspections and periodic inspections of heavy vehicles, using the data provided by Queensland’s Department of Transport and Main Roads for the period of 2012-2013. Negative binomial regression is used to analyse the data. Although the scheme cannot be evaluated completely through the proposed analysis approach, such an evaluation can provide empirical evidence for the effectiveness of periodic heavy vehicle inspection in reducing the number of vehicle defects. The initial exploratory analysis results indicate a large impact of the periodic heavy vehicle inspections on reducing vehicle defects. While 85,447 out of 180,252 vehicles (i.e., 47.4%) inspected under the COI scheme failed the inspections due to defects, only 2,737 out of 38,145 vehicles (i.e., 7.2%) inspected randomly failed the inspections. This is despite the fact that the previous studies have consistently found high rates of vehicle defects in roadside heavy vehicle inspections (Blower et al., 2010). The findings of this study have theoretical and practical implications in the context of the effectiveness of vehicle inspection protocols on vehicle defects and resulting road safety