Traffic Guidance System

Definition and Technical Concept

A traffic guidance system is an intelligent transportation system (ITS) based on modern electronics, computing, networking, and telecommunications that provides road users with optimal route navigation based on their origin and destination, or helps motorists identify the most efficient route via real-time traffic updates. Its core philosophy integrates people, vehicles, and road infrastructure—influencing road user travel behaviour to optimise road network efficiency, prevent traffic congestion, minimise vehicle transit and idling times, and ultimately achieve a balanced distribution of traffic flow across the road network.

System Architecture

A traffic guidance system typically comprises three key components: a traffic information control centre, a communications network, and a traffic guidance dissemination system. Under the framework of intelligent connected mobility, this architecture has expanded into four distinct layers: sensing, network, data, and application. The traffic control centre is tasked with collecting and processing live traffic data across the road network, with its data acquisition unit relying on various sensors including inductive loop detectors, ultrasonic sensors, infrared detectors, radar sensors, and video surveillance detectors.

Main Classifications

Based on coverage and operational scope, traffic flow guidance systems are broadly classified into in-vehicle guidance systems and external roadside guidance systems. In-vehicle guidance systems target individual vehicles (also known as individual vehicle guidance systems), transmitting real-time traffic data directly between the vehicle and the control centre; while the guidance mechanism is highly precise, it demands sophisticated in-car hardware and high-speed communications, making it relatively costly. Conversely, external roadside guidance systems broadcast advisories to groups of motorists via roadside display units; requiring lower capital expenditure and offering rapid deployment, this represents the primary format currently deployed in China. External guidance systems are further divided into urban traffic guidance systems (encompassing municipal street guidance displays, smart parking guidance systems, etc.) and highway traffic guidance systems (including expressway traffic guidance systems).

Core Functions and Practical Value

The primary function of a traffic guidance system is to analyse live traffic flow data and provide motorists with real-time traffic updates alongside route optimisation services, thereby guiding individual driver routing choices to balance overall road network traffic. By capturing real-time road conditions and processing the data through a centralised platform—integrated with satellite navigation and GIS technologies—the system delivers real-time routing advisories via television, radio broadcasts, and Variable Message Signs (VMS) to achieve an evenly distributed traffic flow. Studies demonstrate that under normal driving conditions, the probability of motorists failing to take the shortest route ranges between 6% and 8%; providing dynamic, real-time traffic updates delivers even more pronounced benefits. According to empirical data from Intelligent Transportation Systems deployments in the United States, their application can enhance traffic efficiency by approximately 20%.

Technological Evolution Trends

Traffic guidance systems are transitioning from conventional information broadcasting towards intelligent connected ecosystems. Connected vehicle technology enables comprehensive situational sensing and real-time data sharing, fostering seamless integration between guidance systems and wider traffic management networks. In terms of guidance strategies, split-ratio control selectively delivers routing advisories to regulate turning traffic volumes, thereby preventing congestion from spilling over to adjacent routes. Regarding delivery channels, the system has expanded beyond traditional Variable Message Signs (VMS) to in-car infotainment screens, mobile internet platforms, and smartphone navigation apps, achieving precise, targeted point-to-point guidance.

Technical Limitations

The effectiveness of traffic guidance systems remains subject to several operational constraints. While Variable Message Signs (VMS) can divert traffic effectively within specific corridors, excessive diversion can compromise overall traffic flow or inadvertently trigger bottlenecks on alternative routes. Furthermore, variations in how motorists perceive and respond to dynamic signboards directly affect diversion outcomes, requiring further research into diversion algorithms and driver behavioural responses. In addition, the precision of real-time data collection and the duration of traffic forecasting windows directly influence the accuracy of guidance decisions.