Video and radar detection combine to improve intersection safety and traffic efficiency

Accurate vehicle presence detection facilitates the Transportation Authority to manage and control traffic lights at intersections based on actual traffic demand. Only by having the ability to simultaneously detect vehicles of different distances, different lanes, and different directions can this goal be effectively achieved. Although various techniques are available for detecting vehicles within a certain distance, they are unable to efficiently detect vehicles with such a wide field of view. Combined with video and radar, FLIR's products can achieve such a wide field of view, thus significantly enhancing intersection safety and traffic efficiency.

To meet the needs of today's Transportation Authority, FLIR Intelligent Transportation Systems has developed a cost-effective, single integrated device that combines video and radar-based vehicle presence detection technology to simultaneously detect different distances, different lanes, and different directions. Vehicles. Hybrid video/radar sensors can be used in traffic adaptive systems and puzzle zone protection applications. Traffic light efficiency accurately detects the presence of vehicles at different distances, lanes, and directions, and the presence of vehicles that stop at the stop line: all of this information is critical when forward-looking traffic lights are required. By combining all the test information, the traffic control system can take into account the existing and upcoming traffic conditions, thus more appropriately determining the current and next green light duration. The traffic control system not only manages the intersections it is located in, but also manages multiple adjacent intersections, known as the “traffic adaptive” system.

Traffic (light) efficiency here refers to shortening waiting and/or travel time. Ultimately, costs can be reduced: pure economic costs (idling vehicles cost), ecological costs (CO2 emissions), and psychological costs (disappointment, nervousness).

Today, less than 1% of traffic lights at intersections in the United States have traffic adaptive systems installed. However, the Intelligent Transportation Systems (ITS) industry generally believes that "adaptive traffic control systems" are the most cost-effective and outstanding solutions. In addition, the enormous social and political pressures that require effective control of vehicle emissions require more systems that take into account actual transportation needs.

Confusion zone security

As far as traffic safety is concerned, once there is a vehicle in the puzzle zone, the traffic light controller can be easily alerted by combining detection systems of different distances. In this area, if the traffic light turns from green to yellow, the driver of the car may hesitate to continue driving or waiting for parking. In the former case, the driver may choose to accelerate through the risk of overspeeding and crashing at an intersection; in the latter case, an emergency stop may result in a vehicle rear-end collision.

Confusion zone protection is a method of minimizing the possibility of yellow light being activated when there is a vehicle in the puzzle zone. To achieve this, the traffic light controller must predict whether there is a vehicle in the puzzle zone. By detecting the vehicle in the puzzle zone, the traffic control system can use this information to determine the delayed activation of the yellow light until the problem vehicle safely passes through the intersection. The controller can also decide to extend the duration of the red light in the direction of the collision to avoid potential traffic accidents caused by red light. An additional prerequisite for efficient implementation of the puzzle zone protection is the ability to distinguish between small and large vehicles because the braking distances are completely different. The following statistics illustrate the importance of confounding area protection.

Of the 226 vehicles in the confused district of Damascus, Syria, 38% stopped waiting for the red light, 56% smashed the yellow light, and 6% smashed the red light. A total of about 47% (96 cars) entered the puzzle zone. From this figure, 51% of vehicles are accelerating during the yellow light, 43% are braking in an emergency and dangerous way, and 6% are red.

A similar study in Malaysia showed that 62% of motorists were affected by the sudden yellowing of traffic lights. Among these “affected drivers”, 56% accelerated during the yellow light, 13% braked hard, and 31% smashed past the red light.

The above data may vary greatly depending on driving habits, driving safety education and local traffic regulations. However, the problem of confusion is actually present at signalized intersections everywhere in the world.

Available technology

The existing traffic adaptive and puzzle zone protection system is not only very expensive, but also has a large amount of engineering installation and configuration.

Electromagnetic sensor

The electromagnetic sensor is transmitted to the repeater using wireless communication, and then the detection information is sent to the traffic controller through the access point. Electromagnetic sensors can only detect vehicles at a certain point on the road, making their installation both cumbersome and expensive.

Ground coil

The ground-sensing coil system has existed for half a century and still occupies a large part of the market share, but its installation cost is high and road construction is large. The coil detector is placed under the road surface and can be used to provide real-time traffic information for the waypoint. The installation process often means interruption of traffic flow. Another problem with coils is their high failure rate.

Radar detection

Doppler radar emits continuous waves with a constant frequency. When the frequency hits a moving object, it is changed, and the new frequency generated is returned to the radar and used to determine the speed of the moving object. Pure radar systems require the installation of multiple devices, such as a radar detector at the stop line and at a higher position.

TrafiRadar combined video and radar detection video

Video detection

Video detection has proven to be very accurate and reliable for traffic light management. The combination of digital data and visible light image control makes video detection different from other systems. Instant visual feedback received from the video system helps speed response to an emergency, which is beneficial for managers who need to make quick decisions. However, when it is necessary to simultaneously detect a stop line and a vehicle 100-150 m away, two video detection systems are required to achieve efficient detection, and the installation cost is increased.

FLIR Solution: Accurate and Cost Effective to Improve Crossroad Safety and Efficiency The FLIR Intelligent Transportation Systems Division (formerly Traficon) has developed a TrafiRadar sensor that combines video and radar to accurately detect vehicles at signalized intersections. TrafiRadar is an integrated small sensor that is easy to install and configure and is competitively priced. TrafiRadar uses video and radar detection for different purposes:

̇Video for close range detection, system configuration and operator visualization

̇Radar for medium and long range detection

This method helps to detect:

Vehicles that are approaching 150-200m away from the intersection and are approaching (pre-test)

Vehicles that are close to the intersection 25-150m away and are approaching (confused area detection)

Vehicles that are 0-25m away from the intersection and are approaching and stopping (stop line detection)

车辆When leaving the intersection (away from the intersection)

̇TrafiRadar products are unique in the ITS industry and are ideal for traffic adaptive systems. TrafiRadar sensor: TN_1110_0008_CN 显示 Display radar information on the video image.

视The line of sight is still clear at 150-200m from the stop line.

̇ Distinguish between medium and large vehicles ̇ Different lanes.

为 Features two technologies that interact and complement each other

̇ is an integrated solution in a hardware device

The price is much lower than other existing systems and technologies.

̇ can be installed in 30 minutes.

in conclusion

Combined video and radar-based vehicle presence detection technology helps to accurately detect vehicles at different distances from an intersection. With this feature, it can deploy so-called traffic adaptive systems or provide confusion zone protection. Combining video and radar-based vehicle presence detection technology in a single product enables it to detect the speed and position of vehicles 0-200 m from the stop line. Integrating video and radar detection technology into a single device makes this solution even more cost effective than a single technology solution.