Highway Capacity Manual 2010 provides various factors to adjust the base saturation flow rate for the capacity analysis of signalized intersections. No factors, however, is considered for the potential change of signalized intersections capacity caused by the access point closeing to the signalized intersection. This paper presented a theoretical model to estimate the lane group capacity at signalized intersections with the consideration of the effects of access points. Two scenarios of access point locations, upstream or downstream of the signalized intersection, and impacts of six types of access traffic flow are taken into account. The proposed capacity model was validated based on VISSIM simulation. Results of extensive numerical analysis reveal the substantial impact of access point on the capacity, which has an inverse correlation with both the number of major street lanes and the distance between the intersection and access point. Moreover, among the six types of access traffic flows, the access traffic flow 1 (right-turning traffic from major street), flow 4 (left-turning traffic from access point), and flow 5 (left-turning traffic from major street) cause a more significant effect on lane group capacity than others. Some guidance on the mitigation of the negative effect is provided for practitioners.

An ecodriving speed control algorithm is proposed for a platoon of vehicles at a signalized intersection. Both the running status of the target platoon and the impact of the downstream platoon are considered and analyzed. The acceleration–deceleration profile, instead of speed trajectories, is used in this research as the optimization objective to prevent drivers from idling and to let them clear the intersection during the green light as often as possible. When a platoon is a mixture of vehicles obeying or disobeying the system's guidance, the proposed algorithm will group those vehicles into new platoons according to their permutations (different positions of obedient and nonobedient vehicles). Three illustrative examples are provided to validate the proposed algorithm. Results indicate that when the platoon needs to accelerate to pass the intersection, a smaller headway causes less fuel consumption, whereas a larger headway results in less fuel consumption if the vehicles decelerate to pass the intersection. In addition, the leading vehicle is found to consume more fuel if it disobeys the system's advice; however, if it obeys the system's advice, the fuel consumption for the following vehicles may not increase noticeably.