Abstract: To alleviate the increasing serious traffic congestion and pollution problems on expressways, the impact of carbon emissions was considered based on the classic ALINEA ramp control algorithm. A macrocarbon emission threshold index was proposed by combining real-time carbon emission measurement indicators with occupancy indicators using a macroscopic fundamental diagram. A carbon emission-ALINEA (CE-ALINEA) hierarchical control algorithm was constructed, which considers the carbon emissions reduction of the mainline and ramps as well as the improvement in road network operation efficiency. Furthermore, the control effects of different control algorithms were compared via VISSIM simulation experiments. The results showed that when compared to ALINEA control, the CE-ALINEA control can not only effectively reduce mainline emissions and improve main-line operation efficiency, but also significantly reduce the increase in ramp carbon emissions due to ramp control. Furthermore, CE-ALINEA control can effectively measure mainline carbon emissions and have a stable control effect on mainline traffic by changing the layout of detectors. As the penetration rate of electric vehicles increases, the carbon reduction effect of CE-ALINEA weakens. However, when compared to ALINEA, it continues to exhibit a better reduction effect on ramp carbon emissions.

Key words: tra?c engineering, tra?c carbon reduction, macroscopic fundamental dia-gram, ramp control, VISSIM