The National Tax Administration, which is responsible for the e-TOLL system, requires the data transfer to be uninterrupted and continuous. Therefore, companies providing vehicle location services must undergo a long and tedious certification process to be integrated with e-TOLL. The certification includes not only the GPS device itself, but also the entire network infrastructure, which includes the tracking application, servers and data transmission frequency. Therefore, sometimes the same type of locator, which is much cheaper on popular auction sites, will not be approved by the National Tax Administration if the company providing the localization service has not passed the appropriate certification.