At requests from several insurance companies, more than 100 advisory opinions and expert conclusions on commercial vehicle driver's infringements in the field of compliance with the rules for working and resting times as well as for application of recording equipment (tachograph) in the local and international road haulage operations have been developed from 2008 to 2013. The aim of the research is to investigate the most common infringements of social provisions committed by commercial vehicle drivers involved in road transport accidents (RTA). The data included in this paper refer particularly to infringements committed by the drivers involved in driving vehicles which were registered in the Latvian registry. The paper summarizes and evaluates most common infringements of social legislation requirements for drivers involved in RTA in accordance with the Directive 2009/5/EC of the European Commission and the corresponding Latvian Cabinet of Ministers Regulations No.411 entered into force in 2008. Offences on drivers' allowed work and rest time periods, shortcomings at record keeping and inappropriate use of recording equipment (tachograph) by drivers of commercial vehicles are characterized in this paper based on findings and conclusions of in-depth case studies, advisory opinions and expert conclusions. The paper provides evaluation of infringements of social legislation requirements by their importance in relation to road safety, by type of recording equipment fitted to vehicles, by the quantity and type of offences committed simultaneously, as well as by other minor aspects. It was found that drivers have committed up to 10 different types of infringements at a single case. Most of the infringements discovered should be defined as very serious ones. Even in those cases when only one violation was found, in half of the cases it was defined as very serious infringement. The results of this paper will be further used in the next stage of research comparing the results obtained here with the data from regular roadside vehicle checks on the quantity and type of infringements of social legislation requirements.