The objective of this study is the comparative assessment of driver distraction related risk factors with the explicit
purpose of ranking their impact on road safety. Existing studies were selected and analysed in a set taxonomy, of
which distraction includes 11 risk factors. For each risk factor the applied methodology included rigorous literature
search and selection, analysis of studies in terms of design, methods and limitations and synthesis of findings and
meta-analyses, when feasible. 37 high quality studies were selected and analysed. Results indicate that cellphone
use in any form is the most detrimental type of distraction. Conversation with passengers, cognitive overload and
inattention, and outside factors were found to have a modest impact, while listening to music and operating devices
were found to have an unclear impact. Three meta-analyses were also conducted, determining the proportions of
crashes that occur due to drivers conversing with passengers or operating devices.