The contractor shall provide, upon request, technical assistance services in support of the following activities: • Checks of the test vehicles (light-duty and/or heavy-duty) to verify their suitability for testing (integrity of the exhaust system, absence of error messages in the electronic control unit, good mechanical condition, etc.). • Preparation of the vehicles for testing (adaptation of the exhaust gas system and other components, preparation for the installation of sensors and measuring equipment, vehicle conditioning and driving, etc.), as well as assistance during the execution of the tests. • Restoration of the vehicles to their original condition after the tests and repair of any damage or failures, including dedicated interventions at the contractor's premises. • Specific experimental set-up for vehicle testing requiring advanced expertise in on-board diagnostics (OBD) and high-voltage systems.