Video Surveillance cameras are installed at strategic locations in the city and on the highway for real-time monitoring of traffic conditions. Previousy, sensors and detectors of legacy systems provided the majority of the data that are collected and transmitted back to traffic control centers for analysis and processing. Now, with the rapid pace techonology is improving, in terms of maturity and reliability, as well as the gradual decrease in price, video surveillance is increasingly usedas a completmentary component in the overall intelligent transportation solution.
The main applications of video surveillance cameras in an intelligent transportation system (ITS) include monitoring for traffic flow, congestion, and incidents for bridges, tunnels, roads, and highways. Other important applications of ITS include traffic light and intersection control and enforcement. Tollbooths on highways are also implementing the use of video surveillance cameras for license plate recognition, as well as in the city for restricted access to certain zones at certain time frames. With license plate recognition abilities, video surveillance can compare the license plates with a white list of those who have authorized entry to see if whoever is trespassing has the authority to do so, according to Fabrizio Arneodo, ITS Design and Development Manager at 5T.
Traditional ITS solutions rely on inductive-loop detectors buried under road surfaces to detect when a vehicle passes through. However, these systems are quite a hassle to install and maintain as it involves stopping traffic and disturbing road surfaces to do so, both of which require a significant amount of manpower and money. Unfortunately, it is not uncommon for local governments and public administrations to lack sufficient funds or budget to finance the maintenance and repairs as often as they should. Video surveillance, in this case, becomes an alternative option as they are normally installed on poles, traffic lights, or other elevated positions, which will be comparatively less intrusive than the massive roadwork and construction needed to bury the detectors under road surfaces.
The advancements in network surveillance also make it more worthy for ITS investment. “Aspects that clearly
document the advancement of network video surveillance in traffic solutions are the continuous investments in image quality, which is, respectively increasing resolution for enhanced identification as well as the usage of intelligent video analysis. These aspects offer substantial added value, for example to train stations, airports, and parking lots. Higher resolution in combination with intelligent video analysis enables security personnel to focus on events that really matter.
Increased efficiency and more proactive security are major advantages resulting from these technological advancements,” said a representative at Bosch Security Systems. Taking into consideration that not all locations are suitable or ideal for video surveillance installations, traditional sensors and detectors will still be used in those areas to gather all pertinent traffic data.
In this way, video surveillance and traditional sensors and detectors should be viewed as complementary tools working in cooperation to gather real-time data for ITS solutions as a whole. In relation to ITS, video surveillance is used in two ways: real-time monitoring and video detection. So instead of just providing real-time footage of what is currently happening on the roads, the video with intelligent features is also acting as a detector to gather and analyze data. These cameras not only have to endure harsh weather conditions, humidity, and extreme temperatures on the roads, but be able to monitor clearly despite lighting changes throughout the entire day, and glare and reflection from sunlight or automobile headlights. The cameras will also have to be able to capture up to at least 30 frames per second as vehicles travel at a high speed, especially down the highway.
However, a major factor that prevents its more widespread use is due to its cost. Though surveillance costs have gone down, they are still too costly to be widely implemented for ITS in certain areas. “In Turin we are using cameras in counting, surveillance, and enforcement, but in a limited way, the choice of using cameras for traffic flow counting respect that the classic traffic sensors are mainly due to costs and simplicity in installation, but the technology is mature and accurate,” according to Arneodo.
Real-time Monitoring
Most surveillance cameras in ITS are solely used for real-time monitoring purposes. These surveillance cameras.jpg)
only serve to provide real-time traffic conditions to the traffic control center, and issue a warning if an accident or disruption occurs. The way that ITS solutions are set up and configured are extremely subjected to local laws and regulations when it comes to storage of video data. “In the U.S., traffic video is rarely recorded due to the possible legal and liability issues. All traffic violations are strictly enforced by the police, while the Department of Public Works or Department of Transportation is in charge of managing the ITS solutions.
As previously mentioned, surveillance is used as a complementary device along with the various sensors and detectors in the ITS. Though sensors and detectors are able to provide a vast amount of information, surveillance serves as eyes for the operations or control center, able to provide real-time monitoring.
Video detection
With video analytics, video cameras are able to provide traffic flow measurement and automatic incident detection (AID), allowing them to act as “visual” detectors for ITS. Surveillance footage is processed and analyzed to determine vehicle type and provide vehicle count for the area they are passing by. If any event or situation were to occur, such as being close to or reaching maximum capacity, or an accident taking place, an alert will be sent to the traffic control center for proper addressing. Also, these intelligent cameras can be “trained” to better identify and differentiate the type of instances, and to make decisions after these incidents occur.
This is usually done during the surveillance solutions' initial configuration stage by inputting information such as distance between lanes, legal speed limit, road capacity, weight capacity, camera height, etc. “Assuming that video surveillance comes with intelligence, in the form of video processing, this allows to contribute to ITS in a lot of ways, which is already in practice. The video feeds can provide vehicle counts and speeds, the latter not only for a cross section (like inductive loops), but also along a stretch of a road.
It can also provide automatic checking of parking spaces on motorway services areas (specifically interesting for truck drivers) and providing this information. Automatic number plate recognition (ANPR) allows operators to derive travel times between several locations and or route choice in the network. Video feeds also play a role within advanced driver assistance systems, together with lots of other detectors,” said Thomas Otterstatter, Product Manager of PTV Optima at PTV Group.
One of the advantages of having video detectors over traditional sensors and detectors is that it can measure vehicle position and vehicle movements across several lanes. Also, with intelligence, video surveillance cameras are able to perform ANPR functions especially at tollbooths for toll collections, or to identify those who fail to pay toll. In an urban area, ANPR will most likely be used to verify that all cars entering or leaving a certain zone are authorized to do so. In territories where ITS is integrated with the police, it can aid in law enforcement as well, such as identifying the person violating traffic regulations from his or her license plate and issuing a ticket accordingly.
“Not necessarily regular surveillance technology only pushed the capabilities and benefits of ITS installations, but also the highly sophisticated solutions provided by companies dealing with dedicated ANPR cameras. These are, in many respects, not comparable with security cameras reading license plates (e.g. for parking access), because these special ANPR cameras cover a much wider field of operations like free-flow tolling, enforcement, ANPR dragnet operations. The reason is that these solutions use higher grade sensors (in most case two sensors: one mono for ANPR and one color for environmental scene capture) to cover even higher vehicle speeds with short exposure times and real-time capability," stated Enzio Schneider, Product Line Manager ITS at Basler. Recently, there has been a series of improved features.
Video cameras capture images better than before, so it is able to more accurately identify the plates. It can now more accurately identify the characters on the plates than ever before. The analytics can now adjust accordingly to the size of the license plates and capture images of cars travelling at a speed from zero to 125 miles per hour.
Future expectations
As the concept of smart cities continues to be promoted, the implementation and deployment of ITS will grow in popularity as well. However, there are certain things that must be addressed. “The efficient steering of traffic streams is surely a great challenge that needs to be mentioned here in order to realize concepts for modern mobility and traffic solutions. The growing of digital networks needs to be utilized, which requires significant investment in infrastructure,” said the representative from Bosch. If such investments cannot be made, ITS will not be able to achieve its maximum performance or efficiency, which will in turn, defy the initial purpose of its deployment.