Alternating traffic safely on lift bridge
The City of Duluth Aerial Lift Bridge operators rely on AXIS Camera Station and cameras to monitor the structure and bay and ensure everyone’s safe passage when raising and lowering the lift for ships, vehicles, and pedestrians.
Historic Aerial Lift Bridge links communities
The Duluth Aerial Lift Bridge has been an iconic City landmark since it began operation in 1905. The bridge spans the Duluth Ship Canal, connecting the City center with Minnesota Point (also known as Park Point), a narrow sand island that includes a recreation district and a residential community. In its initial phase, the structure employed a gondola car suspended under the truss to ferry vehicles and pedestrians. In its third decade, the City replaced the gondola mechanism with an elevating roadway.
A bridge operator monitors and controls the raising and lowering of the lift from the pilot house, a small room in the middle of the elevating structure. Cameras both atop and underneath the bridge allow the operator to see whether any vehicles and pedestrians are at the bridge entrance's or on the elevated roadway before raising the bridge. They’re also able to view approaching vessels to determine if their height might interfere with bridge operations.
“Every half hour the operator raises the bridge for sailboats and commercial fishing charters,” says Elysia Hoium, IT Manager for the City of Duluth. “But we’re also a port City. So, 10 months out of the year, when the port isn’t icebound, the bridge also accommodates large cruise ships, barges, tankers, and other vessels passing through the canal.”
During an average week, 30,000 vehicles might traverse the heavily trafficked bridge. At the height of tourist season, that number is considerably higher. Over the course of a year, operators might be lifting the bridge about 4,000 times to accommodate water traffic and maintenance crews.
Improving visibility throughout the span
After decades of relying on an analog camera system to provide critical situational awareness on the Aerial Lift Bridge, Duluth made the decision to upgrade its observation system to digital. “Because the structure is 138 feet tall and spans 390 feet, we were looking for cameras with better image quality and really good zooming capabilities,” says Hoium. “Given the extreme weather conditions we face in Duluth, the cameras needed to be especially rugged, too.”
To address their dilemma, Duluth invested in more than two dozen high-resolution Axis pan/tilt/zoom cameras with laser focus to adorn the Duluth Aerial Lift Bridge, reliably livestreaming images to the pilot house in all kinds of weather from high wind, snow, and ice with temperatures that could range from -45 °C to 49 °C (-50 °F to 120 °F).
“The array of cameras gives the bridge operator a clear view of all the high-risk parts of the bridge, traffic entry points, as well as the whole bay,” says Chris Majerle, Network Administrator for the City of Duluth. “This kind of operational efficiency assures them that no vehicles or people are on the bridge when the span goes up or are in those pinch points when it comes back down.”
Majerle notes that achieving that kind of visibility without cameras would require hiring at least four other individuals per shift to stand outside the structure and visually eye the bridge and surrounding area.
By having the cameras feed directly to AXIS Camera Station, the operator in the pilot house is still able to view, manage, and safely activate the lift even if the bridge loses internet connectivity.
Building a self-contained solution
Another integral technology addition to bridge operations involved the video management system. To complement their existing Milestone-based video technology infrastructure, which utilizes a fiber connection to transmit video feeds from the bridge to the City's data center, Duluth opted to implement an additional layer of localized monitoring by installing AXIS Camera Station video management system in the pilot house and hard-wire the cameras to it.
“It was important that the livestream segment of the system be self-contained since the loss of video would necessitate interrupting operations,” explains Majerle. “If latency or outages were to happen, operators would see skips in their coverage or lose video feeds on the bridge all together."
A video wall in the pilot house provides live views of the cameras. The bridge operator can manipulate the pan/tilt/zoom of individual cameras using a joystick to redirect the field of view and zoom in on details. The video also streams to the City’s Milestone Systems data center servers for recording, archiving, and searchability in case footage needs to be reviewed for investigations.
“By having the cameras feed directly to our local AXIS Camera Station, the operator in the pilot house is still able to view, manage, and safely activate the lift even if the bridge loses internet connectivity,” says Majerle.
Creating a hierarchy of camera control
While the bridge operator has primary control of the cameras during lift operations, certain City departments like police and fire can view and manipulate the cameras during an emergency event.
“We’ve instituted a hierarchy of permissions,” explains Elysia Hoium. “For instance, police and fire department staff can temporarily take control of certain cameras, but the Coast Guard can only view the livestream and doesn’t have the authority to change any camera’s direction. And then within the police or fire department, emergency management protocols dictate who is responsible for maneuvering the cameras.”
Sighting daredevils and impatient drivers
Dave Campbell, Duluth’s Aerial Lift Bridge supervisor, shares that their new Axis cameras have enabled operators to see incidents with far greater clarity. With their legacy third-party cameras, they couldn’t discern many details to share with police, fire, or ambulance services if they spotted someone suspicious or in a dangerous position on the bridge.
“Now we get a very clear picture of the individual, what they’re wearing, even facial features,” states Campbell. “So, we can give responders a pretty accurate description. We can also tell police the license plate number of any motorists circumventing the traffic gate to beat the lift.”
The cameras enable bridge operators to swiftly identify and address issues like pedestrians still on the walkway or hanging on the bottom, despite the horn warning that the bridge is about to lift.
For example, Campbell recalls an incident where the bridge operator noticed the cameras catching someone throwing an electric scooter into the bay. “The operator was able to zoom in on the individual and note the logo on their shirt,” said Campbell. Sharing the logo information and detailed descriptions with the police led to a swift arrest.
An efficient way to keep everyone safe
“We couldn’t operate the Aerial Lift Bridge without those cameras,” maintains Campbell. “With so many areas of the structure where somebody could get hurt, a lift operator working alone couldn’t possibly verify everyone’s safety before activating that lift.”
Managing those cameras through AXIS Camera Station keeps them self-contained and protected from possible outages on the citywide fiber network. “It’s all about reducing risk,” declares Chris Majerle. “As long as the bridge has power, those cameras keep on working.”
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