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Broadband Access
Roseville gets smart about its traffic network
California city extends IP network capabilities over existing twisted pair copper infrastructure
by Sean Buckley
The idea of networking a city’s traffic lights with IP-based gear is becoming the new rage in the traffic industry as the technology allows traffic departments to not only increase internal visibility, but also enables residents to plan their daily commute.
Case in point is Roseville, Calif. For Roseville, the notion of integrating IP networking into its traffic network is really the reinvention of a legacy process.
Before the traffic industry even thought about integrating IP capabilities into their respective equipment (sensors, cameras, etc), Roseville began linking its traffic lights in 1988. The technology used — one that was likely considered state of the art at the time — was done through 2400 baud modems.
Flash forward to 2005. As the city began evaluating how it could upgrade its traffic system, it realized two facts: not only were traffic systems going to have IP-addressable components, but it could carry these capabilities on their existing copper infrastructure.
After examining various copper bonding options, the city found that Actelis’ Ethernet over Copper solution was the best fit. As part of this process, Roseville found that even over poor wire net splices, the Actelis equipment could still perform well.
“We had all of this twisted pair copper in the ground, and asked, how could we leverage that?” said Jason Shykowski, senior civil engineer for the city's Traffic Operations Public Works — Engineering. “While we heard about going to fiber for networking, we figured well, if they can do DSL to homes, why can’t we use that in the traffic industry?”
Integrating copper/fiber
Like other cities and towns, Roseville owns its copper and fiber infrastructure. This enables them to avoid pricing fluctuations from local service providers such as Roseville-based neighbor SureWest.
Leveraging six to eight copper pairs over the Actelis ML 638 unit, Roseville has been able to extend its network to each signal one to two miles without any degradation in speed. However, the majority of its traffic signal-to-signal links are no more than a half-mile apart.
But already the city can extend these connections further.
“Since we started installing Actelis’ EoC gear, they have had one software upgrade that actually increases the bandwidth per pair,” Shykowski said. “It allows us to leverage the hundred-plus miles of copper in the ground and use that to complete our high-speed IP network without having to replace it all.”
To complement its copper network, Roseville is simultaneously building out fiber trunk lines to support its IP cameras from Newton, Mass.-based Industrial Video and Control (IVC). Paired with Actelis' ML600, which provides network connectivity and power to IVC's new camera (IVC PTZ-310-NC32), the two companies claim the joint solution can reduce camera set up time and installation costs.
Figure 1. Video Surveillance Solution.
By connecting its cameras to these fiber trunk lines, Roseville is able to make it easier for city residents to view its real-time camera feeds for traffic. A concern was that users would have to get MPEG-4 codecs installed on their home computers, so they left the video coding in M JPEG compression.
Since each video feed runs at speeds of up to 4 Mbps, the question then became how many cameras they could have up at once before exceeding their bandwidth.
To alleviate potential bandwidth blockage problems, Shykowski said Roseville started to break up the city into links of six to seven cameras from a central trunk line. After initially deploying a 25-pair copper line trunk line, Roseville found that solution to be unwieldy.
Roseville had the good fortune of timing as Actelis enhanced its product with support for fiber. Shykowski said that having this option meant they would not have to deploy a separate box in areas where it needed to deploy fiber.
“At the same time, Actelis came out with its 638 switch which had fiber ports on it as well,” he said. “We said that’s the perfect mix: we can have a fiber trunk line and have no more than seven intersections spread off from that trunk line and use that same switch throughout for both the copper and the fiber.”
Maintaining uptime
With more than 400-500 Atelis EoC units installed, Roseville has made continued progress with the deployment of its EoC-based traffic network.
Along with enabling it to leverage its copper network, the Actelis gear helped maintain something else: network uptime. With cable cuts being a common occurrence in Roseville, the city has been leveraging the spanning tree protocol to maintain constant uptime.
Maintaining uptime is a constant battle. This is because all of the city’s communications lines are underground and can be no deeper than nine inches.
“It gets hit a lot,” Shykowski said. “What spanning tree does is it allows us to keep up our communications lines and reroute communications to the various signals when something gets hit by a contractor, which happens a lot.”
The benefits of spanning tree extend beyond the Roseville city limits. The city's traffic department is building a regional traffic operations center for all of the Sacramento area. This process will effectively connect all of the agencies over the fiber trunk lines.
“What this allows us to do is keep up the inter-agency communication using spanning tree should one of our fiber trunks lines are hit,” Shykowski said.
A flexible foundation
Similar to other nearby cities such as Sacramento, Roseville is seeing that the traffic industry is taking up the IP challenge with their new products for more flexibility over legacy systems.
By migrating to an IP-based traffic system, Roseville gains increased visibility into its traffic system.
Taking it a step further, the IP system has enabled the traffic department to become more proactive in managing the traffic system. In essence, the IP system, including its IVC cameras, enables the traffic department to not only route pertinent data to any location, including the Web and remote monitoring station, but to hook up other devices including its CMSs and traffic signal controllers.
Through the Actelis 638s, Roseville's Traffic Operations department is using VLANs to separate out different network items going across the same pairs of copper.
Given the new bandwidth capabilities the network has, the traffic department has developed a cozier relationship with the IT department while extending bandwidth to other city buildings.
“We’re actually providing disaster recovery backhaul for the whole city network over our traffic signal interconnect network,” Shykowski explained. “The stuff that used to be 2400 baud that we used to change signal timing is now becoming a central part of our communications infrastructure for the entire city and that’s because we decided to go to IP.”
Logically, the other entity that could benefit from this system would be local law enforcement and related agencies. While Shykowski sees the value in providing that service, they aren’t biting.
“We’ve discussed it with them, but our local police and fire have other things on their mind right now,” he said. “Although we have attempted to bring them in several times, nothing has really happened on that front.”
Nonetheless, Roseville's efforts are getting the attention of other nearby cities, including Rockland, a smaller community that does not have as robust a traffic signal system. Roseville will work with Rockland to set up a copper and fiber-based network for their traffic system.
One of Roseville's biggest interconnection points will be with Sacramento County. Hoping to have that connection up and running in the next 12 months, it will be able to extend capabilities into other areas, including Cal Tran, Tech City and Elk Grove. In essence, Roseville will be connected with the whole Sacramento region.
Like other traffic departments, Roseville is seeing the traffic industry integrate IP into their systems. Still, Shykowski says that besides vendors such as IVC, the majority of the surveillance camera industry thus far has been slow to break the analog habit.
While the camera industry may be slow to the IP draw, there are other IP-based capabilities that, while right now too expensive to deploy, could be taken advantage of in the future.
For instance, there are noise sensors that can detect auto accidents by measuring certain decibel sound patterns. These IP-based sensors, which go on a traffic signal head, can automatically turn on the camera and notify traffic operations that there’s a traffic accident. From there, the traffic department can not only adjust traffic flow and direction, but also notify the police department an accident has ocurred.
In addition, the city is looking into building a Wi-Fi network throughout the city for city workers to conduct work orders and then for public Internet access.
“What we can do is unlimited,” Shykowski said. “It’s all stuff that’s possible because of the IP network.”
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