The fast development of all sorts of telematic devices to support or partially substitute a drivers tasks has also led to some concern for the possible detrimental effects that such devices may have on the safety of driving. A three year research project has been carried out to develop criteria and procedures that can be used to assess the nature and extent of these detrimental effects. A further aim was, to make the assessment procedure as simple as possible, so that it can be used by relatively non-expert users. Moreover, these procedures aim to limit the number of otherwise necessary (expensive) field tests. A general conclusion is, that current knowledge on this subject is not yet sufficient to provide a comprehensive set of checks and this has resulted in the following compromise for the testing procedure: -A checklist for safety characteristics of telematic devices is proposed based upon known safety effects of task load changes: overload and underload: this checklist can be employed by non-scientists to provide a first screening of unsafe characteristics. -A laboratory test has been developed that uses an ordinary Personal Computer. The test emulates a simplified driving task and can accommodate a functional simulacrum of a telematic device. The user is also provided with a set of criteria to produce an assessment of the safety effects. This test can also be used by non-experts. Furthermore, recognising that in the current state of affairs field testing will still often be necessary, an attempt was made to formulate guidelines and criteria for the setup of these tests