Traffic simulations for 2035 takes leap of faith

Traffic simulations for 2035 takes leap of faith
Smoky Mountain News
December 10, 2008
By Becky Johnson • Staff Writer

As the debate over the Southern Loop rages on, a faceless cadre of number crunchers have been assigned a seemingly impossible task: predict who will be driving on N.C. 107 and why 25 years from now.

The answer could ultimately propel or table the Southern Loop, a proposed bypass around Sylva meant to alleviate congestion on N.C. 107. While 107 serves a dual purpose — both a commercial strip and commuter corridor — the question for planners is whether a new road would divert enough traffic from N.C. 107 to do any good.

"Does a new road in that vicinity offer relief to 107 or does it not?" said Pam Cook, a transportation engineer working with the Jackson County Transportation Task Force. "Does it offer enough help to be worth continuing to look at in more detail?"

For now, DOT's number crunchers are deploying a complex formula to figure out how many cars will be on the road in the year 2035. The magic number will be unveiled in January.

The numbers being plugged into the formula are coming from the Jackson County Transportation Task Force. The task force met last week to finalize their input.

"What is Jackson County going to look like in 2035? Where is the employment, where is the population going to grow, where will schools grow, how will the college grow?" Cook asked. "That's what we've been looking at for the past couple months."

The numbers being plugged into the simulations assume the same rate of growth over the next 25 years as the past 25 years, from homes to jobs to population.

County Commissioner William Shelton, who sits on the task force, questioned whether this was an accurate assumption. Shelton said at some point the holding capacity of the land couldn't keep up with infinite growth at today's levels. Shelton said there could be a paradigm shift in the county's future.

"At some point that same template is not going to work, so at what point do you make that determination?" Shelton asked.

DOT planners told the task force not to get too caught up in the details.

"Don't get too concerned about these growth tables beyond five years," said Ryan Sherby, community transportation planner for DOT and the Southwestern Commission.

Cook said the projections could be revisited in five to 10 years.

"We plan the worst-case scenario," Cook said. "If we can back off some, great."

Considering DOT plans to buy up right-of-way for the Southern Loop in 2015, revisiting the projections in 10 years could be too late to change course.

Shelton again expressed concern that the numbers being plugged into the model are flawed.

"I think it is a fairly safe assumption that the growth pattern we have experienced over the last 30 years isn't going to continue indefinitely," Shelton said. "In that case, how are we going to get data? How do we create a model based on what we don't know?"

Cook said the DOT doesn't have a magic globe, but can make a fairly safe bet.

"You make your best effort. It's more than a guess," Cook said.

All in the formula

Short of standing in the middle of the road with a clipboard to ask drivers where they're headed, the task force will rely on the DOT's formula to accurately predict who will on the road and where they're going to be headed.

While the DOT knows how many people drive on N.C. 107, it doesn't know whether a student commuting to Western Carolina University stops off for a sausage biscuit at McDonald's every morning, or whether a professor picks up their kid from band practice on the way home every day.

While straight-up commuters might be candidates for a bypass, the commercial pull of Wal-Mart, Lowe's, Ingles, gas stations and fast-food joints could have drivers seeking out N.C. 107 anyway.

"I think we need to look at what is on 107. If all the commerce and services are on 107, then this connector is not going to take 50 percent of the traffic off or even 25 percent off," said Susan Leveille, a member of the task force representing the Smart Roads Alliance. "We need to figure that out somehow."

DOT claims it has a formula that will answer that question.

"We don't do a survey of every single person and map out every person's movement, but we know our model does a pretty good job," Cook said. "It takes into account someone who goes to work, leaves for lunch and comes back. The equations have taken years and years of research to come up with."

Cook said the DOT's formulas have proved accurate in Jackson County when used for present-day traffic counts. Applying the formula to today's demographics — population density, employment, schools, stores and the like — the number crunchers estimated how much traffic should be on which roads. When compared to actual traffic counts — captured by counters across the road — the predictions were accurate within plus or minus 10 percent, Cook said. Cook said that was exceptionally accurate.

But whether the formula will still hold true when projecting traffic for 2035 is another story. There could be entirely new variables, and current ones could be obsolete.

One likelihood is public transportation to and from WCU by then. Allen Grant, a task force member representing Jackson County Greenways, said future public transports up and down N.C. 107 should be factored in to the equation.

"I think we need to put these things into it," said Grant.

Pat Brown, dean of education and outreach at WCU, agreed.

"I think public transport would relieve some pressure," said Brown.

But Cook said public transportation wouldn't put a dent in N.C. 107 traffic and won't be factored into the 2035 traffic simulations.

"I don't know that it would be enough to help," Cook said.

Western's giant role

A giant wildcard in predicting traffic 25 years from now is Western Carolina University. If the school grows, so grows the county. And growth is most certainly in Western's plans.

"It seems the elephant in the room is Western's growth projections," said Dr. Cecil Groves, the president of Southwestern Community College and member of the task force.

Western plans to more than double the number students taking courses on campus from 7,000 to 15,000 by the year 2035, according to figures shared by Brown.

A lot of that growth could be self contained, however. WCU has aggressive plans for building on-campus housing, coupled with a commercial district to serve students. Known as the Millennial Campus, plans call for a new town center with restaurants, coffee shops, even a grocery store.

"The intent is to support that population," Brown said. "The students would live there, eat there, have their services there and spend time studying there."

If so, traffic on N.C. 107 may not be as elevated as it would under the current model that assumes students buzz into Sylva for most of their needs.

Of the 8,000 additional students WCU foresees, 3,000 would live on campus and 5,000 off-campus.

Jay Spiro, a member of the task force representing the Jackson County Smart Growth Alliance, asked how certain WCU is that the growth will come to fruition.

"When you start talking about 2035, it is definitely guess land —fantasy world is more like it," Brown replied.

Groves said that regardless of the exact numbers, WCU would certainly grow and the role of N.C. 107 as a gateway would only become more important over the years.

What's next?

After the traffic projections for 2035 are unveiled to the task force next month, the real work begins. The task force will start to develop ideas for solving transportation issues, namely congestion.

"They'll brainstorm alternatives to help relieve any problem areas," Cook said.

The result will be a "comprehensive transportation plan," but the problem areas getting the most attention will be the main drag of N.C. 107 and U.S. Business 23.

The goal of the task force's transportation plan will be reducing congestion during rush hour periods, regardless if it occurs any other time of day, Cook said.

Leveille questioned whether such an approach is realistic. Rush hour congestion is part of life, she said.

"The goal to have no traffic congestion is lala land. It is just not achievable ever," Leveille said.

Cook said she hopes the duration of rush hour congestion would be taken into consideration. If it's just a short window, building the Southern Loop might be overkill versus other solutions.

"I would certainly say if it is only 30 minutes I would hope they look at congestion management," Cook said.

Congestion management experts within DOT have already taken a gander at N.C. 107. With so much publicity brewing over the road, the experts made a trip here from Raleigh to see if any quick fixes jumped out at them.

"That's a practice I would like to see in DOT, for congestion management to come in and offer simple suggestion if there are any," Cook said.

The idea of fixing N.C. 107 congestion without building a new road will be explored more fully as part of yet another more formal study currently under way.