Calibrating the Robertson’s Platoon Dispersion Model on a Coordinated Corridor with Advance Warning Flashers

Abstract

Platoon dispersion (PD) is the foundation of traffic signal coordination in an urban traffic network. PD describes the phenomenon by which vehicles depart from an upstream intersection as a platoon and begin to disperse before they arrive at the downstream intersection. Recently, advance warning flashers (AWFs) have been applied in many high-speed corridors. There is a need to update the traditional PD model to include the effect of AWFs. This paper examines the traffic flow dispersion patterns when an AWF is present and tests the hypothesis that the AWF will affect PD on a coordinated signal corridor. Platoon vehicles, which are not affected by the operation of the AWF, are used for comparison. Results show that when the AWF effect is included in the PD model, the smoothing factor F of the Robertson's PD model ranges from 0.11 to 0.13. This range is smaller than the smoothing factor without the AWF effect. The platoon

Real‐time predictive coordination based on vehicle‐triggered platoon dispersion in a low penetration connected vehicle environment

“…Since parameter t a ( t cyc,k ) is a time‐dependent variable, F cyc,k could be different in different cycle times. Compared to the traditional models using time‐independent parameters [39, 41], these time‐dependent parameters better describe the dynamic platoon dispersion effects.…”

“…Robertson's platoon dispersion model has been studied under different traffic conditions, such as mixed traffics [31][32][33][34], considering turning flows [35] and extra flows from street segments [36], considering pedestrian flows [37], and considering bus flows in the homogeneous condition [38]. In addition, many methods have been proposed to better calibrate the parameters using link travel time [39][40][41] and arrival flows [42,43]. At the same time, the platoon dispersion model is also embedded in the CV-based coordination control.…”

“…Since parameter t a (t cyc,k ) is a time-dependent variable, F cyc,k could be different in different cycle times. Compared to the traditional models using time-independent parameters [39,41], these timedependent parameters better describe the dynamic platoon dispersion effects. Equation (1a) reveals that the current arrival traffic flow q down (t ) at a given time instant t, is a weighted combination of the downstream arrival platoon at the previous time instant t-1 (i.e.…”

“…q down (t − 1)) and the upstream departure platoon T s ago (i.e.q up (t − T )). In other words, the predicted downstream arrival flow q down (t ), by the recurrence platoon dispersion model [41,46] with time-dependent parameters, is derived as follows,…”

Impact of the Link Length on the Delay in Two-Way Signal Coordination

“…The purpose of signal coordination is to allow the upstream discharged vehicles to pass the downstream intersection with as little stopping as possible during the green period. Considering traffic flow in one direction, as the amount of dispersion increases, the proportion of vehicles that can pass during the limited green period gradually decreases, resulting in a gradual decline in the benefits of signal coordination [4]. When the platoon disperses to a some specific extent, there is no longer a significant difference between coordinated control and isolated control.…”