Automated vehicles (AVs) are rapidly evolving and have gained increasing attention from researchers due to their tremendous traffic management and safety advantages. While several studies discussed the implications of Cooperative Adaptive Cruise Control (CACC) technologies for capacity, few had a comprehensive approach to the impacts of CACC-equipped vehicles (Cooperative AVs) on motorway traffic management and sustainability. According to both NHTSA and SAE, CACC is considered level 1 automation. Nonetheless, the performance of CACC vehicles under each scenario can be demonstrative of the performance at higher automation levels. This paper evaluates the impacts of Cooperative AVs on motorway traffic capacity, speed, and ecological sustainability, comparing them against Regular Vehicles (RVs). A micro-simulation model in PTV VISSIM was developed to analyze the interaction of Cooperative AVs and RVs in interurban traffic scenarios. The study assessed the impact of Cooperative AVs on critical traffic metrics, including capacity, speed, flow, vehicle delay, and CO₂ emissions. Various penetration levels of Cooperative AVs (0%, 20%, 40%, 80%, and 100%) were evaluated in a mixed traffic environment alongside RVs. Results showed that Cooperative AVs significantly improve traffic performance. At full penetration, road capacity increased by 85%, average speed by 65%, and traffic flow by 80%. Additionally, vehicle delays were reduced by 75%, and CO₂ emissions decreased by 40%, underscoring both traffic efficiency and ecological benefits. These findings highlight the potential of Cooperative AVs to transform motorway traffic management by improving flow and sustainability. However, challenges remain, including the unpredictability of human drivers, mixed traffic complexities, and the need for advanced Vehicle-to-Everything (V2X) infrastructure. This study provides essential insights for policymakers and planners to better integrate Cooperative AVs into future transportation systems.

 Every year many people are fatally injured or killed on the roads. The number is still quite high, even if it is decreasing from year to year. Although there are fewer accidents on the roads since the epidemic, the number is still relatively high. To minimize the number of road accidents, it is important to understand which types of roads have the highest number of collisions and what the accident forecasts are for the coming years. The purpose of this article is to forecast the number of accidents on Polish roads according to their type. The study consisted of two parts. The first included a forecast of the number of road accidents for 2022–2031, based on an analysis of annual data from police statistics on the number of road accidents in Poland in 2000–2021. The second part of the study focused on monthly data from 2000–2021. In this case, a forecast was also set for the period from January 2022 to December 2023. The results of the study indicate that even after analyzing annual statistics, the number of incidents can be expected to stabilize in the coming years. This is mainly due to the expansion of expressways, especially highways, and the increase in traffic volume on Polish roads. It should be noted that the current epidemic is distorting the results.