In life, seconds can mean lives.
Nowhere is this more evident than with emergency first responders. When it involves fire, life safety and security, first responders are the first line of defense, keeping residents safe and restoring order to communities. But to do that job effectively, one element is critical—access. When the Pennsylvania Department of Transportation (PennDOT) needed to replace the Brighton Road Bridge over I-376 in Brighton Township near Pittsburgh, construction and bridge removal presented an access challenge for area first responders. That is, until the ITS-based Emergency Vehicle Conflict Warning System (EVCWS) provided an intelligent and elegant traffic solution.
A call for help
Infrastructure ages. And when it does, it needs to be replaced. In deciding to replace the Brighton Road Bridge over I-376, known as the Beaver Valley Expressway, PennDOT sought to upgrade the bridge and raise the clearance underneath it. Scheduled for completion in fall 2011, the $8.5 million project was launched in 2009. The project involves removing and replacing the Brighton Road and Tuscarawas Road bridges with new structures, as well as rehabilitating Brighton Road between Dutch Ridge Road and Tuscarawas Road. This is a critically important location to the township: more than 7,222 vehicles, on average, use Brighton Road each day. But the Brighton Road Bridge serves another strategic purpose.
“Brighton Township Emergency Medical Services (EMS) provides first responders for several surrounding communities, as well as for a 5-mile section of I-376. And the Brighton Road Bridge is at an interchange in the middle of the township. Taking the bridge out of service would have essentially cut the township in half,” explained James MacKay, P.E., a Pittsburgh-based senior traffic engineer for AECOM, a global services provider. “There are also three fire stations in the township: one main station and two smaller ones. They handle more than 400 calls per year, and at least 60 of those involve critical emergency care. You’ve got to remember, when accidents occur on an interstate between cars moving at high speeds, you’re usually not talking about minor fender benders.
“With the bridge out of service, the township’s EMS could only go in one direction on the interstate. To respond to a call in the other direction, they would have to take a 5-mile detour down I-376 and then come back on the other side of the interstate. And with three separate stations involved, a specialized vehicle or piece of equipment might be isolated on the wrong side of the township when an emergency strikes. In short, removing the bridge from service could dramatically affect response times. But PennDOT was very sensitive to these concerns, and eager to develop responsive alternatives.”
Originally proposing to construct the bridge using half-width construction—to keep half of the bridge open at all times—PennDOT sought to provide continuous access to the bridge for the emergency first responders. But when PennDOT assessed the cost of redoing the bridge using half-width construction, it was prohibitively expensive. And the half-width process would have taken two years to complete. So PennDOT decided to demolish the entire bridge and build a new one—in a single year.
Next, PennDOT offered to install strategically placed temporary emergency turnarounds—gravel passageways in the median—that emergency vehicles could use to change directions quickly, reducing the maximum detour length from about 5 miles to just 2,000 ft. However, the local fire department raised a substantive concern. Without new acceleration lanes to accompany the turnarounds, large, slow-moving emergency vehicles would have to enter, cross or merge with faster-moving traffic on I-376, creating potentially serious conflicts. And there were sight-distance concerns in both directions, since cars must traverse hills on both sides of the interchange.
Another solution involving flat signs was proposed, but this idea gained little traction at the public meeting on the subject; many feared that drivers would simply ignore the signs. At the same public meeting, while the different alternatives were being debated, AECOM’s MacKay presented a different idea.
“The Minnesota Department of Transportation (Mn/DOT) had developed some very interesting and practical strategies for managing traffic in, around, and through construction sites,” MacKay added. “They developed a safety system using changeable message signs to warn drivers of approaching construction vehicles. For example, a given construction vehicle operator could activate changeable message signs to alert drivers that a slow-moving construction vehicle was about to cross the road. The similarity between that scenario and ours in Brighton Township was striking. It occurred to me that we could adapt their system to our situation.
“So, I raised this idea at the meeting and we explored further options. In looking to adapt Mn/DOT’s solution to our situation, I suggested we could augment the system by equipping emergency vehicles with emergency preemption technology. This would enable first responders to control the changeable message signs. And that proved to be a workable solution for everyone.”
A traffic-signaling expert who previously worked for PennDOT, MacKay presented two options for signal pre-emption: siren-activated preemption and optical preemption using an infrared light-activated system. Preemption normally allows approaching emergency vehicles to automatically trigger traffic signals, giving the emergency vehicles a green light and restraining all other traffic with red lights. But in this case the technology would control the changeable message signs to alert drivers that an emergency vehicle is about to cross the roadway. Because the optical system would have required additional equipment be installed on all the emergency vehicles, the consensus option was siren-activated preemption technology; after all, every emergency vehicle was already equipped with a siren.
Combining radio signals, switches and relays, six changeable message signs, central control software, and sensors, the siren-activated system was deployed along the critical I-376 construction area. The central control software—the brain behind the system—remotely monitors all of the devices on the project. The web-based EVCWS also allows the contractor to monitor and operate the system, and it even gives the contractor manual oversight capability from a remote location. While providing a safe crossing for first responders, the system also complies with the Federal Highway Administration’s Final Rule Subpart J, even as it increases safety, enhances mobility, collects historical data about the work zone and increases motorist satisfaction.
But the proof, as they say, is in the doing. And by all accounts, the EVCWS works. To notify drivers that an emergency vehicle was entering the highway, the system was activated 43 times during the recent construction period—without incident. MacKay believed three factors made the implementation so successful.
“PennDOT showed both consideration and fortitude in implementing this system. First, they were sensitive to community concerns, and they were determined to find a workable solution for all stakeholders. They didn’t have to do that; they could have just closed the bridge and installed the turnarounds and left it at that. But that’s not how they work. They’re very responsive to their constituency and its needs, especially when it concerns life-safety issues on their roadways. Next, I give tremendous credit to Mn/DOT. They put the “toolbox” together. And in doing so they actually exceeded federal requirements for safety. The thoroughness of their work made adaptation to our scenario much easier; that made a big difference.
“Finally, we must credit the Brighton Township officials, who were willing to adjust to the situation and try new technology to solve an old problem. It was clear that complete removal of the bridge wasn’t their first choice, but they understood the financial pressures PennDOT was under and they agreed to try this unusual proposal.”
Mn/DOT’s Intelligent Work Zone (IWZ) Toolbox is a unique document with a decidedly pragmatic philosophy. As described in its introduction, “The IWZ Toolbox has been prepared as a guideline for selecting an appropriate Intelligent Work Zone (IWZ) System for existing work zone traffic issues and to mitigate anticipated issues on scheduled projects. The IWZ System descriptions contained in this toolbox are intended as brainstorming material and should lead to practical solutions to a project’s unique problems. The examples are purposely left void of many dimensions, except where particular distances are highly recommended, and engineering judgment is required to customize the system to a project.”
Citing the IWZ Toolbox as a foundation, MacKay also credited the American Traffic Safety Services Association and its ITS Safety and Mobility Solution booklet for its significant contribution to the EVCWS.
Infrastructure ages. And when it does, it must be replaced. PennDOT needed to replace the Brighton Road Bridge. But taking the bridge out of service for any amount of time presented a serious life-safety concern for Brighton Township, and for travelers along I-376. With the bridge out of service, first responders faced potential detours of 5 miles or more when responding to emergencies. To develop a workable construction solution, PennDOT teamed with Brighton Township officials to create the Emergency Vehicle Conflict Warning System.
An adaptation of one of Mn/DOT’s Toolbox strategies, the EVCWS eliminated a lengthy detour and provided a safe, effective and timely way for first responders and construction personnel to warn drivers that emergency vehicles were about to cross the road. And timeliness was key. Because if first responders were forced to traverse an extra 5-mile stretch of a major interstate to serve their communities, the delay would mean lives.