Table 1 Basic parameters of simulation.

Road

Road network: 2*2 intersections; the length of the connecting section of the intersections: 470 m–490 m, with six two-way lanes, channelization set at 30 m at the entrance of the intersections; width: 3.5 m

Vehicle

Speed distribution: [20 km/h, 60 km/h], the ratio of vehicle types: 1: 99 (large cars: small cars), the ratio of buses to emergency vehicles: 99:1 in the large car

Flow

Initial: the flow of stage 1: 1000 v/h; the flow of stage 2: 500 v/h; the flow of stage 3: 1000 v/h; the flow of stage 4: 500v/h. Every 3600 s multiplied the flow of each stage by the coefficient of change x, 0.5 < × < 2

Intersection and Signal Control

The intersections were numbered A, B, E, G, the initial plan of the intersection all adopted 4-stage signal control. The stages were stage1: north–south straight; stage2: north–south left; stage3: east–west straight. Stage4: turn left from east to west; straight-right vehicles and straight-going vehicles were released at the same time; the signal control period was 160 s; the interval time was 3 s for yellow light and 2 s for all red; Tstage1: 45 s, Tstage2: 20 s, Tstage3: 45 s, and Tstage4: 20 s

Scene

Undersaturation, oversaturation

Data Collection and

The road section number, lane number, whole road section density, flow, and vehicle speed were collected, with an acquisition interval of 600 s

Evaluation Parameters

The average number of stops and average delay time