Connected and autonomous vehicle (CAV) technologies are known as an effective way to improve safety and mobility of the transportation system. As a combination technology of connected vehicle and autonomous vehicle, CAVs share real time traffic data with each other, such as position, speed, and acceleration. CAVs are able to increase roadway capacity since they require narrower lane width and headway. And CAVs can coordinate their maneuvers while weaving in which will result an improvement of capacities at weaving areas. Also, CAVs enable the information shared between vehicles and traffic signals. The coordinated operation among CAVs and the communication between CAVs and traffic signals will improve the throughput at signalized intersections and lead to a higher intersection capacity. To evaluate the influence of CAVs on freeway capacity and intersection mobility, new guidelines should be established. Microsimulation software is used to simulate CAVs as well as AVs and regular vehicles. Case studies are conducted both on freeways and signalized intersections. It is concluded that CAVs can improve the freeway capacity and the improvement of capacity also increases with the increase of freeway speed limit. Also, CAVs can help reduce the capacity drops before and after the on-ramp, off-ramp, and weaving area as the CAV penetration rate increases. With V2I/I2V communications, CAVs can effectively improve the efficiency of signalized intersections. The vehicle emissions under all scenarios are also generated. CAVs can reduce vehicle emissions by as much as 33.47% compared to regular vehicles and 11.26% compared to AVs. The findings in this research could establish knowledge on how CAVs will improve mobility in the highway systems.
