In the context of the rapid advancement of the global urbanization wave, traffic congestion has become a persistent and difficult problem in the development of modern cities. Statistics from the World Bank are startling. The economic losses caused by traffic congestion in major cities around the world amount to 2% – 4% of their GDP. This huge amount of losses covers various aspects such as the waste of people’s time, the additional consumption of fuel, and the reduction in the efficiency of logistics transportation, severely restricting the sustainable development of cities and the improvement of residents’ quality of life. In such a severe situation, the Intelligent Transportation System (ITS) has emerged as the key to alleviating urban traffic pressure. Geomagnetic sensors, as the core sensing devices in the intelligent transportation system, are revolutionizing the logic of traffic management with their unique technical advantages and bringing new solutions to urban traffic congestion alleviation.

I. Geomagnetic Sensors: Technological Innovation and Efficient Operation System

(I) Innovative Breakthroughs in Physical Principles

The working principle of geomagnetic sensors is based on the phenomenon of disturbances in the Earth’s magnetic field. There is a stable magnetic field with an intensity of approximately 0.5 – 0.6 Gauss on the Earth’s surface. Although this magnetic field is invisible and intangible, it constantly affects the operation of geomagnetic sensors. When a vehicle containing ferromagnetic materials enters the detection area, the metal components of the vehicle act like a stone thrown into the “lake surface” of the calm magnetic field, causing changes in the local magnetic field pattern. The magnitude of this magnetic field disturbance is considerable, reaching 5% – 15% of the Earth’s magnetic field.

To accurately capture the vehicle information behind these magnetic field changes, three – axis magnetic sensors play a crucial role. Like an “observer” with keen perception, it can precisely obtain key parameters such as vehicle presence, driving direction, and speed through the composite analysis of the magnetic field vectors in the X/Y/Z three directions. In actual road deployment scenarios, the system mainly relies on the Z – axis magnetic field intensity change curve to identify the traffic state of vehicles. After numerous practical verifications, the accuracy of this detection method is over 99%, providing a reliable data basis for subsequent traffic decisions.

(II) Comprehensive Upgrade of the System Architecture

Modern geomagnetic detection systems have constructed a scientific and efficient three – level architecture of “sensing layer – transmission layer – decision – making layer”, with each level collaborating closely to ensure the stable operation of the system.

At the sensing layer, advanced anti – interference magnetoresistive sensors are used. These sensors have a strong adaptability. Whether it is a large truck or a small and flexible electric vehicle, they can be accurately detected. Their unique design can effectively resist interference from the external environment, ensuring stable operation in various complex traffic environments and precisely perceiving every movement of vehicles.

The transmission layer uses 2.4GHz wireless communication technology, which is a significant breakthrough. Compared with traditional loop detection technology, traditional loops require laying a large number of cables to transmit data, which not only has high construction difficulty and cost but also is very inconvenient for later maintenance. In contrast, 2.4GHz wireless communication technology completely gets rid of the shackles of cables. A single receiver, with its powerful signal coverage, can cover 32 detection nodes within a radius of 300 meters, greatly improving the data transmission efficiency and range.

The decision – making layer is equipped with edge computing devices, which are like the “intelligent brain” of the entire system. These devices can quickly process the transmitted real – time data and have a strong data storage capacity. The data processor can store historical data for up to 180 days. After analysis and processing, it can output 16 traffic parameters, providing rich decision – making bases for the signal control system and making the control of traffic signals more scientific and reasonable.

 

II. Practical Congestion Alleviation: Data – Driven Signal Optimization Strategies

(I) Building a Dynamic Traffic Flow Sensing Network

Geomagnetic sensors are carefully arranged at key nodes of the road, forming an all – round and three – dimensional detection matrix, like countless “intelligent eyes” installed for urban traffic.

At the entrance of intersections, geomagnetic sensors are installed 50 meters in front of the stop line. This location is carefully selected as it can monitor the vehicle arrival rate and queue length in real – time. Through the analysis of this data, traffic managers can predict changes in traffic flow at intersections in advance and provide accurate bases for adjusting the signal cycle. For example, when it is detected that the vehicle arrival rate is high and the queue length is gradually increasing, the system can appropriately extend the green – light time to reduce the waiting time of vehicles.

In the middle of the road section, a pair of sensors is installed every 200 meters. This pair of sensors can calculate the interval average vehicle speed by accurately calculating the time difference when a vehicle passes through the two sensors. When the vehicle speed drops abnormally, the system can quickly identify potential congestion points and issue timely warnings. This real – time monitoring and warning mechanism helps traffic managers take timely measures to relieve traffic and avoid the further deterioration of congestion.

In the exit area, geomagnetic sensors focus on monitoring the vehicle dissipation rate. Once it is found that the vehicle dissipation is slow and may cause overflow and grid – like congestion, the system will adjust the signal control strategy in a timely manner to give priority to releasing vehicles in the exit lane and ensure smooth traffic. After deploying a traffic flow sensing network based on geomagnetic sensors in the CBD area of Beijing, the traffic efficiency during peak hours has increased by 27%, effectively alleviating the traffic pressure in this area.

(II) Promoting the Transformation of Signal Control Paradigms

Traditional fixed – time traffic signal control schemes often lead to the waste of green – light time and the aggravation of traffic congestion because they cannot be flexibly adjusted according to real – time traffic flow. Nowadays, the geomagnetic – driven adaptive control system is gradually replacing traditional schemes and becoming the new trend in traffic signal control.

The phase optimization algorithm is one of the core technologies of the adaptive control system. It can dynamically allocate the time of each phase according to the real – time collected traffic flow data. In Nanshan District, Shenzhen, the application of this algorithm has achieved remarkable results, reducing the green – light idle time by 42%. This means that the waiting time of vehicles at intersections is greatly shortened, and road resources are utilized more efficiently.

Green – wave coordinated control is also an important means for geomagnetic sensors to assist in traffic optimization. By obtaining information such as the dispersion of vehicle platoons through geomagnetic detectors, the system can dynamically adjust the coordinated phase difference between intersections. In the Wenyi Road test section in Hangzhou, 7 consecutive intersections have achieved green – wave traffic in this way. When vehicles travel between these intersections, they can pass with continuous green lights, reducing the travel time by 35% and greatly improving the road traffic efficiency.

In addition, geomagnetic sensors can also identify special vehicles such as buses and ambulances by using the characteristics of magnetic field waveforms. When a special vehicle is detected approaching, the system will automatically trigger a priority – passage signal to ensure that these vehicles can pass through intersections quickly. In the Suzhou Industrial Park, the application of this technology has increased the bus punctuality rate to 92%, providing a more reliable guarantee for residents’ travel.

III. Efficiency Revolution: The Significant Advantages of Geomagnetic Sensors Compared with Traditional Detection Technologies

Although the initial investment in geomagnetic sensor devices is 14% higher than that of traditional detection technologies, in the long run, their maintenance – free characteristics reduce the total cost over a five – year period by 58%. This is because traditional detection technologies, such as induction loops, require regular maintenance and replacement, resulting in high maintenance costs. Moreover, during the maintenance of traditional loops, the road needs to be excavated, which not only affects the normal traffic on the road but also causes huge indirect economic losses. Take Shanghai as an example, the traffic delay losses caused by the maintenance of traditional loops exceed 230 million yuan every year.

Among the many advantages of geomagnetic sensors, their weather tolerance is particularly outstanding. Geomagnetic sensors with an IP68 protection level have excellent environmental adaptability and can operate stably in extreme environments ranging from – 40°C to 85°C. In contrast, traditional loop detection technology has a significantly increased false alarm rate in rainy and snowy weather due to reasons such as wet road surfaces, seriously affecting the detection accuracy.

Geomagnetic sensors also perform well in terms of road compatibility. The renovation project of Chang’an Avenue in Beijing is a good example. Whether it is an asphalt road surface, a concrete road surface, or a permeable brick road surface, geomagnetic devices can work reliably. Moreover, its installation depth error tolerance is as high as ±5cm, greatly reducing the construction difficulty and cost.

In addition, geomagnetic sensors have strong electromagnetic anti – interference capabilities. Through the adaptive filtering algorithm, they can effectively eliminate strong electromagnetic interference from subways, trams, etc., with a detection error rate of less than 0.1%. This characteristic enables geomagnetic sensors to still operate stably in complex urban electromagnetic environments and ensure the accuracy of detection data.

Geomagnetic sensors, with their advantages in technical principles, system architecture, congestion – alleviation applications, and comprehensive efficiency, provide practical solutions to the problem of urban traffic congestion. With the continuous development of technology and the wide – spread application, it is believed that geomagnetic sensors will play an even more important role in the future intelligent transportation field, contributing more to the efficient operation of cities and the convenience of residents’ travel.