The methods currently used to assess the impact of Intelligent Transport Systems (ITS) services on traffic safety and efficiency are mainly based on expert assessments, statistical studies or traffic models that need further development. There is no structured, uniform evaluation method to compare the impact of different ITS services and their different configurations. The impact of ITS deployment on the road network adjacent to motorways or expressways is usually not taken into account for simulation studies. The approach presented in the paper takes into account the impact of ITS deployment on road traffic efficiency and safety in areas including major roads and alternative routes. The paper presents a methodology for testing the effectiveness of the implementation of a selected ITS service, which is ramp metering. An approach has been applied in which the impact of ITS services is analyzed with the use of a test road network in macro, meso and microscopic transport models. The evaluation of solutions was carried out on the basis of key traffic efficiency indicators. Surrogate measures were used for the assessment of the impact of ramp metering on road traffic safety.