Imagine the flow of vehicles traveling Interstate 81 on an average day trying to make their way through downtown Carlisle.
It isn’t that much of a stretch. It’s a real scenario drivers, residents and public safety officials see with unsettling frequency in the borough.
Carlisle Theatre manager Leslie Sterner knows when there’s a crash on I-81 just by looking out of the window of her office.
“I can usually tell without even going outside when this happens. If I look out the front window, I can see the tractor-trailer trucks creeping by,” she said.
“We’re pushing 40,000 vehicles through streets that were not designed for that and through an urban community that has its own traffic,” said Sgt. David Miller of the Carlisle Police Department.
Usually, Pennsylvania State Police try to keep one lane flowing in each direction if there is, for example, a two-vehicle crash that ends up in the median. A fatal crash, however, can shut down one or both directions of the highway for several hours, Miller said.
Detours and road closures take place for reasons other than a fatal crash. Miller recalls a crash in which there were no injuries, but the truck had dumped its entire load. Officials had to bring in a skid loader to clean up the mess before the highway could be reopened.
Matthew Frampton of South Central Pennsylvania Highway Safety said there have also been crashes in which the frame of the truck broke. It took hours to clean up because emergency services personnel had to wait for the recovery company to fix the truck so it could be moved.
When a crash happens and one or more lanes are closed, the Carlisle police supervisor on the street makes the decision as to whether a detour plan should be put into effect, Miller said.
If so, the first call is to Capt. Robert Wertz of the Carlisle Regional Special Police so those volunteers can be called out to facilitate traffic control at predesignated detour routes.
In the meantime, police officers work intersections that are known problems until the fire police can be there, but Miller said he can only sustain the staffing for so long.
Depending on the circumstances, Wertz could have as many as 10 to 12 people out monitoring intersections.
“Once he gets in place, once his people start showing up, I start pulling my officers back off the intersections because there’s still other things happening. There’s other police incidents going on,” Miller said.
Most of the detour plans come from experience and are worked out, in part, between the fire police and the county. The plans are based on where the crash occurs and how many lanes it affects.
For example, if a crash closes both lanes between the Newville exit (Exit 37) and the Allen Road exit (Exit 44), officials wouldn’t want both north and southbound using Walnut Bottom Road (Route 465) because that road isn’t built to handle that volume of traffic, Wertz said. As a result, the southbound traffic would be taken onto Route 11 and the northbound traffic would be sent onto Route 465.
Detours avoid sending traffic through the heart of the downtown for closures between Exit 44 (Allen Road) and Exit 45 (College Street) and closures between Exit 45 and Exit 47 (Hanover Street) by using Allen Road and Walnut Bottom Road to detour for the former and Walnut Bottom, Willow Street and South Hanover Street for the latter.
When a crash closes down the interstate between Hanover Street and York Road (Exit 48), traffic has to go through the downtown. That’s when officials limit turning at key points, such as the Square, to keep traffic moving.
“The worst thing you can do is turn those trucks at the Square,” Wertz said.
Miller said the challenge with moving tractor-trailers through town stems from their length, inability to stay close to the car in front of them and inability to start and stop quickly. Also, while people driving cars can be directed down a side street, the trucks can’t.
“If you give me 40,000 cars, we’ll just deal with it. In fact, we might just monitor the intersections and let the lights do their work,” he said.
For detours between Hanover Street and York Road, southbound traffic may be pulled off the interstate at the High Street exit, and directed straight through town on Route 641, High Street, and rejoin I-81 at Allen Road. Northbound traffic would exit at Hanover Street and rejoin the interstate at the Middlesex exit (Exit 52).
There’s no question the detours slow things down, but even as the traffic is moving, public safety officials are communicating with each other to stop traffic at some intersections and let it go at others. They then reverse the flow to keep things moving.
“There’s a lot that goes into it, but I think some drivers don’t have that perspective or patience, and that becomes an issue,” Miller said.
Those drivers go around the fire police who may be blocking off a road or pass through cones that have been set up to block off a street. They may also turn where they are not supposed to.
For the most part, people are patient, but Miller said there is a percentage that only think about where they need to go and will yell at the safety personnel.
“They don’t understand that what we’re doing is actually planned out. We didn’t just willy-nilly decide to close an intersection. We’re out there because something else has happened. Our first priority is to safety,” Miller said.