An Evaluation of the Use of Odds Ratios to Estimate the Association between Mobile Phone Use and Safety Critical Driving Events
Authors: Nick Reed a, Charlene Hallett b, Stephanie Cynk a, David Jenkins a
Abstract: This paper investigates the odds ratios for mobile phone use when driving for a sample of vehicles from fleets in the USA, UK, and New Zealand, employing a similar protocol to that used by Hickman, Hanowski & Bocanegra (2010). The event data was collected from vehicles of various types, ranging from commercial to private vehicles. Vehicles used the SmartDrive in-vehicle camera and telematics systems to record video, audio, location and speed information in response to kinematic triggers. Data was reviewed at SmartDrive by trained observers and coded for the safety criticality of the event (safety critical event (SCE) vs. baseline epoch (BE)) and the associated factors observed over the time-course of the event. The SmartDrive dataset comprised a total of 103,264 epochs recorded from the start of April 2012 until mid-October 2013 and was evaluated by SmartDrive expert reviewers. Of this total number of epochs, 14,097 were classified as SCEs and 89,167 as BEs. SmartDrive provided data on the incidence of events and associated factors to TRL for further analysis, particularly for tasks relating to mobile phone use. Similar to the findings of Hickman, Hanowski & Bocanegra (2010), handsfree mobile phone use was associated with a significant odds ratio of less than one for the occurrence of a SCE. In contrast to the findings of Hickman et al. (2010), results from this investigation revealed that both handheld mobile phone use and manual interaction with the mobile phone (texting/dialling) were also associated with a significant odds ratio of less than one. These results are used to discuss the advantages and disadvantages of the use of naturalistic driving data, the method of classification employed by trained observers, and the use of odds ratios as an approach for investigating the effects of engagement in secondary tasks while driving has on driver behaviour and driving performance.
Keywords: Road Safety, Odds Ratios, Naturalistic Driving, Mobile Phone, Driver Distraction
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