Facing projections that more than 350,000 people will move to Williamson County over the next 25 years, county officials and residents heard recommendations from traffic experts on how to handle and prepare for future growth on Wednesday.

The first is the creation of a capital improvement projects plan to lay out priority transportation projects for county roads over the next several years.

"Clearly, the biggest issue is the dedicated funding source and ability to build that into a true CIP plan," said Greg Dale, with McBride Dale Clarion.

The second is revisiting the county's comprehensive plan — specifically its land use policies in eastern Williamson County — to consider whether allowing less dense residential development can help "put the brakes" on the influx of new residents.

Funding options

Capital improvement plans don't work without a funding source. Williamson County has no clear mechanism to pay for future capital and operational improvements to county-owned roads.

Without taking state roads into account, $378 million will be needed for those projects.

Williamson County's highway department has a budget of $11.5 million, with $5.7 going toward highway and bridge maintenance alone.

The question of how to generate the revenue needed spurred discussion among county commissioners.

Consultants who compiled traffic strategies for Williamson County's unincorporated areas, where most growth is expected in coming years, presented several funding scenarios, from a countywide property tax increase to a property tax hike coupled with an impact fee that would be limited to unincorporated areas.

While a considerable chunk of drivers who use those roads are just passing through Williamson, the bulk of new traffic in coming years will be generated from new residents in the county's eastern portion.Some commissioners opposed the idea that future tax hikes would be limited to those who don't live in one of the six municipalities.

"Why did anybody even suggest…for only unincorporated people paying?" said Commissioner Barb Sturgeon. "I don’t understand why you would even think that."

Sturgeon also asked whether it would be possible to make people who live outside the county to pay for road improvements.

County Mayor Rogers Anderson explained that county property tax revenue isn't used for city road projects, and vice versa.

"Folks in municipalities don't pay for anything in unincorporated areas. Let that sink in for a minute," Anderson said.

"Our experience has been, when you tax everybody, the municipalities are going to ask for their share," said L. Carson Bise, president of TischlerBise.

Three of the five suggested funding scenarios call for a property tax increase. A countywide, nine-cent property tax hike, for example, would generate more than $371 million.

Two other scenarios called for an annual transportation utility fee, but commissioners were put off by the fact that such a fee isn't legal in Tennessee and would require a change in state law.

Land use policies

Consultants also recommended that Williamson County review its 10-year old comprehensive plan and its existing land use policies in eastern Williamson County.

A large chunk of the county is zoned RD-1, which requires no more than one dwelling unit per acre. Under existing zoning, there's a remaining capacity of 23,000 additional units in that area alone.

"That drip of continued development of that area is eventually going to get to the point where its significant contributor to the traffic issue," Dale said.

The question will be whether the county should increase the acreage required for new homes.

"The point is, there needs to be a multi-faceted approach that involves not only identifying what projects to build and where the funding's going to come from, but also revisiting those fundamental (land use) policies," said County Planning Director Mike Matteson. "I don’t think there’s anybody that’s saying what that should result in, but it makes sense to go back out to the community and determine what that should be."

Matteson said the county will likely begin to review its comprehensive plan next summer.

The overall findings of the transportation study will be presented to the full county commission and planning commission later this fall.

Key Findings



Williamson County is projected to gain roughly 353,000 more residents over the next 25 years.



Roughly 35 percent of that new population growth, or 124,000 residents, are expected to move into unincorporated areas of the county.



While existing congestion in unincorporated areas is highest near Hillsboro and Sneed Road, those same levels of traffic are expected on roadways in eastern Williamson County by 2040.



Currently, about 52 percent of people traveling on county and state roads are not Williamson residents.

Full build out of the county's rural areas could potentially bring up to 58,000 new dwelling units.

Reach Elaina Sauber at esauber@tennessean.com, 615-571-1172 or follow @ElainaSauber on Twitter.