As a new landmark in the centre of Jiangning sub-city, Xiaolongwan Area of Jiangning District in Nanjing has developed into a centre for commerce & business and culture & entertainment, as well as a demonstration area for the ecological and happy residence. After nearly 2 months’ preparation and cooperation between Traffic Police Brigade of Jiangning Branch of Nanjing Public Security Bureau and Duolun Technology, the cool traffic technology of “automatically adaptive control of regional traffic” has been officially applied to four intersections at Xiaolongwan Area.

● What Is “Automatically Adaptive Control of Regional Traffic”? ●

“Automatically adaptive control of regional traffic” is based on the traffic condition in the region. The technology optimizes the traffic organization of regional roads and intersections, and applies ubiquitous perception methods such as the multi-targeted radar to perceive traffic parameters at the intersections in time including the length of queue, the occupancy rate, and the headways. It also applies the real-time automatically adaptive optimized algorithm to dynamically optimize the timing of traffic signals (red & green), reduce the parking times and delays of cars, and avoid wasting time when no vehicle passes the intersections, so as to relieve traffic congestion and provide citizens with better experience when travelling.

● Why Do We Choose Xiaolongwan Area? ●

Traffic Police Brigade and Dongshan Squadron of Jiangning Branch of Nanjing Public Security Bureau, along with Duolun Technology, investigated on the spot and took comprehensive discussion.

With the continuous promotion of Urban and Rural Construction Bureau of Jiangning District, four intersections were selected to be optimized and constructed with automatically adaptive control of regional traffic, including “Xiaolongwan Rd-Zhuxin Rd”, “Xiaolongwan Rd-Xinting Rd”, “Xiaolongwan Rd-Yangjiawei Rd”, and “Xinting Rd-Xingning Rd”.

The Pilot Area Presents a “T” Shape

The traffic around the four intersections is complex with heavy vehicle flow. There are schools, large residential areas, complex commercial areas, governmental service agencies, parks for citizens, and other types of buildings.

Traffic Congestion during Morning and Evening Rush Hours

Before optimization, traffic in Xiaolongwan Area was controlled mainly by single signals. Although some road sections were controlled by one-way green wave with fixed periods and schemes, the automatically adaptive control of signals was not well applied. Traffic congestion and severe occasional overflow easily took place, especially during after-school hours and rush hours in both morning and evening.

优化前空放空待情况明显

● What Have We Done? ●

提升出行体验 显著提高通行率（建议点击右下角放大观看）

The innovative application of “automatically adaptive control of regional traffic” was launched at Xiaolongwan Area in April 2020, from the following three aspects:

01

Optimization of inductive green wave based on multi-targeted radars. Targeted at the coordinated sections (three successive intersections on Xiaolongwan Rd), the two-way green wave has been realized, and the traffic flow of intersection branches is perceived in real time to automatically adjust the duration of green lights, and as a result, the chances that no vehicle passes on the branches when lights are green are reduced, the temporal and spatial distribution of traffic flow is balanced, and the bandwidth of green wave and driving experience on the trunk roads are improved.

02

Dynamic coordination of trunk roads based on multi-targeted radars. The traditional scheme of fixed periods sets different timing models in different periods, which can neither handle with the abnormal changes of traffic flow nor smoothly control the flow. Applying multi-targeted radars to perceive the vehicle flow at intersections, the optimization adopts the strategy of dynamic coordination of trunk roads to dynamically and periodically changes the signals and automatically adapt to the different vehicle flows at intersections based on green wave of trunk roads in each intersection. As a result, fewer vehicles need to queue up, and the vehicle detention, which is caused by huge vehicle flow, is avoided.

03

Control of overflow based on multi-targeted radars. The length of the section between intersections of “Xinting Rd-Xingning Rd” and “Xiaolongwan Rd-Xinting Rd” is only 180 metres. As the automatically adaptive control strategy of trunk road signals is implemented at Xiaolongwan Area, the overflow probably takes place in the section and causes severe congestion. To cope with the problem, control of overflow is conducted at the intersection of “Xinting Rd-Xingning Rd”, adopting several methods of automatically adaptive control to coordinate including asymmetric release, central cooperative intervention, and green wave of branches in different periods.

After the optimization, the saturation of the left-turn lane at the east entrance of the intersection of “Xiaolongwan Rd-Yangjiawei Rd” decreases from 1.33 to 0.67 in morning rush hours, with the total saturation of the intersection from 0.86 to 0.77. The two-way straight travel time between the sections of “Xiaolongwan Rd-Zhuxin Rd” and “Xiaolongwan Rd-Yangjiawei Rd” sums up to 160 seconds, less than the earlier 242 seconds. The optimization is effective, allowing more vehicles to pass the intersections and improving citizens’ driving experience. 

● Our New Efforts and Goals in the Future ●

With the opening of the surrounding Longhu Tianjie Comprehensive Business District, traffic flow will be changed rapidly in the future. Duolun Technology will adopt the platform of “Intelligent Transportation Joint Research Office” to continuously track and study the traffic flow and optimize the automatically adaptive algorithm of signal control to meet people’s travel demand and alleviate traffic congestion.

      Based on the analysis technology for big data, Duolun will also further improve the signal control with automatically adaptive signals and meticulous setting, so as to achieve the intelligent control of the whole area. Duolun will also strive to achieve automatic optimization of signals during the whole process and realize the closed-loop management through continuous improvement, in which it fulfills the corporate mission of “making roads smoother and traffic safer” with the help of science and technology.