« back to listing

Technology leap

The proven accuracy and reliability of SmartSensor HD has made it a viable alternative to loops for traffic detection applications in Denmark. Wavetronix’s Don Leavitt reveals more

Something revolutionary is happening in the kingdom of Denmark. Similar to the rest of Europe, the Scandinavian nation has traditionally relied on loops for real-time traffic detection; in fact, loops have been so effective, many European transportation agencies are reluctant to even consider other technologies. But now, after extensive testing, the Danish National Road Administration (Vejdirektoratet) is discovering the benefits of radar, and the high-resolution accuracy of SmartSensor HD.

Currently, the Danish National Road Administration is using SmartSensor HD in place of loops for traffic management and queue warning detection on arterial roads. Wavetronix is represented in Denmark by Olsen Engineering A/S, an authorized Wavetronix distributor. Olsen Engineering has established a strong presence throughout Scandinavia and the Baltic region, and according to Hanneke Spijkers Arlgade, has earned a reputation for excellence in many areas of road traffic management, particularly in the integration of technologies and services that increase mobility and improve the environment. “We provide system solutions for traffic regulation, traffic guidance technologies, enforcement, road safety and parking,” explains Arlgade, a marketing consultant at Olsen Engineering.

Right: The Wavetronix SmartSensor HD uses the latest technology to collect consistently accurate traffic data in high definition

Viable alternative
SmartSensor HD operates in the 245MHz bandwidth and produces a radar beam with five times greater resolution than other radar traffic detection devices. The sensor is built on Wavetronix’s core Digital Wave Radar technology, so it is easy to set up and does not need continuous calibration. “That is a main advantage of the sensor,” she continues.
Armed with high-definition radar, SmartSensor HD sees all vehicles within its field of view and not just those detected in predefined zones. It features a unique dual-radar design that performs like a dual-loop speed trap, measuring the time that it takes for a vehicle to pass from one beam to the next to create accurate speed data for individual vehicles. It is that high level of performance that attracted Olsen Engineering. “This is an incredibly accurate radar,” Arlgade suggests. “It can provide per-vehicle speeds to within 4mph, and it also provides more precise vehicle classifications.” Plus, she adds, it is easy to install and configure. “In some ways, it is almost the same as loops, and in other ways, it’s better.”

Left: Dual Radar determines vehicle speed by measuring the delay from one radar beam to the next. This also determines vehicle direction

Loops’ legacy
The comparison to loops is high praise in Europe, where loops have set the detection standard for decades. “Loops meet the tough vehicle flow error specifications required by many ITS applications, and they are the standard by which all other detectors are measured,” she says. One reason for that, she explains, is their versatility. “They measure flow and occupancy and they can estimate vehicle speeds. They can be used to activate traffic control devices or for congestion and incident detection.”

Loops have been a proven technology for many years, and traffic professionals – particularly in Europe – are skeptical of how other detection technologies will perform. “Loops offer a well-defined zone of detection and they are an excellent choice when it comes to traffic statistics where you need a high level of detail. When they are properly installed and maintained, loops perform well in all weather and in both high and low traffic volumes.”

However, loops do have challenges, and Arlgade acknowledges that installation and maintenance are key factors. “Loops are installed in or under the road, and the process takes quite a bit of time and can be expensive,” she says. “It can also have a negative effect on traffic flow.”

Also, roads can be a very hostile environment and in-ground detectors such as loops generally require more maintenance than aboveground devices. “To repair loops, you need to block the road, which interferes with the flow of traffic, and the work can be very time-consuming,” Arlgade feels. “But it can also be very expensive. Doing the work and staying safe often requires very expensive equipment, and on many occasions the work is conducted at night to minimize traffic disturbances, so the agency is forced to pay overtime wages.”

Right: Denmark’s enthusiasm for SmartSensor HD is spreading, with sensor installations popping up throughout Europe

These costs – combined with the impact that loop installation and maintenance can have on traffic – have led many transportation agencies, including Denmark’s road authority, to seek alternative, non-intrusive devices. “Roadside technologies are relatively easy to install and do not require any intrusive reconstruction of the roadway, so installation does not interfere with traffic flow,” Arlgade suggests. “This is a big advantage, especially for primary road networks where the more equipment you can place at the side of the road, the better.”

Tested and proven
Unfortunately, most non-intrusive technologies have failed to provide the same level of performance as loops, so transportation officials have been reluctant to deploy them.
“In order to be considered as a viable loop replacement, roadside devices have been required to be a stable technology that operates independent of weather conditions,” Arlgade says. “In addition, they’ve been required to meet the same tough error specifications.”

Digital Wave Radar is the first non-intrusive detection technology to show real promise as a replacement for loops, and the benefits of radar made the technology an attractive alternative for the Danish National Road Administration. The administration decided to pursue aboveground radar detection as part of its long-term traffic management plan and in 2008 it initiated a rigorous test to identify devices that meet minimum performance standards. The published test summary states: “The Danish National Road Administration wishes to enter into framework agreements with two suppliers of detectors designed for installation over the road; and with two suppliers of detectors designed for roadside installation… This test is to ensure the quality of the detectors… Suppliers whose detectors meet the set minimum requirements will be invited to tender.”

Left: Officials in Denmark have found SmartSensor HD to be a viable option for loop replacement

The test – which was conducted by ÅF - Hansen & Henneberg in Farum, Denmark – evaluated a number of radar traffic sensors, including SmartSensor HD. The devices were compared against three sets of loop speed trap pairs, and the report noted that “since there is great uncertainty in count reference data, the overall assessment is made based on the accuracy of speed data”. Although several devices met minimum requirements, test results show that SmartSensor HD was the only device that performed within speed accuracy requirements for all six days of the test.

Based on the results of this test, the Danish National Road Administration entered into a framework agreement with Olsen Engineering for the SmartSensor HD in early 2009, and the first sensors were installed shortly thereafter. So far, the administration has been pleased with the project and with the performance offered by SmartSensor HD. “The sensor’s accuracy has been beneficial for the Danish National Road Administration’s traffic information applications, such as queue warning, traffic guidance and ITS,” Arlgade states.

Enthusiasm for SmartSensor HD as a viable replacement for loops is spreading. Olsen Engineering has also entered into a framework agreement with the Swedish National Road Administration, which has installed several SmartSensor HD units on the road between the Stockholm Airport Arlanda and Stockholm city as part of a project connected to the ITS World Congress show that was held there in September 2009. Additionally, the SNRA is using the sensor in Varberg, Sweden, as part of its innovative ‘Ghost Driver’ wrong-way detection application.

Even more traffic detection applications are being discovered as acceptance of SmartSensor HD and Digital Wave Radar spreads. The work that Olsen Engineering has conducted to identify SmartSensor HD as an effective alternative to loops has paved the way for these innovative sensor deployments, and Denmark is leading the charge in the leap from loops to non-intrusive technologies.

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Republished from Pulse Magazine with the permission of Wavetronix. For further information about Wavetronix's products, please click here
 

There are currently no comments.