After years of planning, more than a year of construction and about $10 million, the South Helena Interchange is set to open to commuters Tuesday.

The interchange will change the face of transportation in Helena, and it serves as a major piece in the effort to revamp the Interstate 15 corridor from Montana City to Lincoln Road.

The new access likely will ease rush-hour traffic at the Capitol Interchange, while possibly adding new traffic to Saddle Drive, Colonial Drive and Broadway. Helena's third interchange provides a new choice for commuting workers and an improved connection to Montana City via the Frontage Road.

The South Helena Interchange also includes a new feature legislators advocated statewide in 2005 - a roundabout connecting the interchange's on- and off-ramps to Colonial and Saddle drives and the Frontage Road.

According to the Montana Department of Transportation, the new feature should reduce wait times for drivers, cut down on certain types of accidents and reduce air pollution while increasing fuel efficiency.

The interchange also will serve as a seed for growth along the east and west sides of the interstate. One development has already been approved for residential and commercial lots, and another is in the planning stages.

But perhaps the most significant story of the interchange is the way it came about - a close working partnership among local, state and federal officials and private developers moved the costly, complex project forward.

"This really is a model project as far as partnership goes," MDT spokeswoman Charity Watt Levis said. "(Everyone) came to the table with something to offer and moved this project forward. Everybody really worked together and put their resources in."

U.S. Sen. Max Baucus, D-Mont., worked with the state's congressional delegation and his colleagues in Washington, D.C., to secure $11.5 million in federal money for projects along I-15 in Helena.

Helena, Lewis and Clark County and Jefferson County officials all approved donations of needed right-of-way to the project.

The developers of the Nob Hill subdivision, on the west side of the interstate, and the Padbury Ranch subdivision, a proposed 700-acre development on the east side of the interstate, donated land for the interchange. The development groups also donated about $1 million in engineering work for the project.

Helena City Manager Tim Burton said the private-public partnership was critical to the success of the project.

"We all kept our nose to the grindstone, and we all did collectively what was best for the region," he said.

Robert Peccia, the managing member of both subdivision development corporations and the owner of the engineering firm that designed the infrastructure, said the two groups of landowners stepped to the plate when they realized the project was high on MDT's priority list.

"Obviously, it gets complex with so many agencies involved, but I think it worked out pretty well," Peccia said. "From what I can tell, I think it's turned out absolutely outstanding."

Levis said the project's cost will exceed $10 million, but final figures weren't available last week. The lead contractor, Helena Sand & Gravel, had bid $9.9 million on the project. Levis said some of the overrun was due to needed blasting work that unexpectedly cropped up during the project.

Round and round we go

State lawmakers in 2005 passed a joint resolution encouraging MDT to implement roundabouts in more road projects, and Helena's new circular intersection was the first major roundabout conceived in Montana.

"They don't work at all intersections, but it is something we're now looking at when they make sense," Levis said.

Roundabouts ease the flow of traffic, reduce vehicle emissions, eliminate traffic-signal maintenance costs and cut the number of vehicle collisions, injuries and fatalities.

Drivers entering the roundabout must yield to vehicles already traveling counterclockwise through the intersection, but wait times should be significantly less than at a signal-controlled intersection, and traffic should flow more quickly through the roundabout, Levis said.

"They increase efficiency, because you don't have to come to a stop and wait and wait," she said.

Shorter wait times mean less idling for vehicles - increasing fuel efficiency and reducing emissions.

Levis said MDT will save about $5,000 annually in power and maintenance costs because the intersection doesn't need a traffic signal.

Using Federal Highway Administration numbers, Levis said the roundabouts reduce injury accidents by 76 percent, cut fatal accidents by 90 percent and reduce pedestrian injuries by 40 percent.

"You're going at slower speeds, and you've eliminated the right-angle collision," she said.

Construction began on a smaller roundabout in Kalispell after the Helena project kicked off, and that intersection was completed first. While Helena's interchange features a single-lane roundabout, MDT is planning double-lane roundabouts in Billings.

Traffic impacts

Preliminary traffic estimates show large increases in daily trips on Saddle Drive, Colonial Drive, Broadway and California Street after the interchange opens.

Traffic along Broadway, for instance, is estimated to double according to projections developed using 2005 traffic counts.

But Levis and Burton said the interchange will likely decrease traffic at the busy Capitol Interchange and in other areas.

"In most cases the difference is negligible and in most cases, the connection to the interchange actually reduces traffic because some households will leave the subdivision and go to the Frontage Road or to the interstate rather than going through town on their way to work and, similarly, they will return on the same route," Levis said.

Burton said city commissioners have directed him to keep an eye on the interchange's effects on traffic. If improvements are needed, the city will begin discussing necessary projects. But he cautioned against jumping the gun.

"We need to see what the real impact is, not just the projected impact," he said. "We could be pleasantly surprised in some areas.

"If there are unintended consequences … then those are issues we have to deal with," Burton added. "I think MDT did a good job. I don't expect any surprises, and I do expect some drastic improvements on how traffic moves through the area."

Burton also noted the interchange is only a part of a series of improvements slated for the I-15 corridor. The overall project, which includes the Custer Interchange and the widening of portions of Custer Avenue, Cedar Street and I-15, will drastically change Helena's transportation network.

Mark your calendar

The official opening ceremony for the South Helena Interchange is set for 11 a.m. Tuesday. U.S. Sen. Max Baucus, who’s helped secure $11.5 million for I-15 improvements in the area, will join other officials and project partners for a ribbon cutting and refreshments.

Custer Interchange still moving forward

The initial design of the Custer Interchange has been completed and is under review by Montana Department of Transportation officials.

Montana Department of Transportation spokeswoman Charity Watt Levis said the alignment and grade design represents about 30 percent of the needed engineering work.

One of the projects largest hurdles is the acquisition of right-of-way needed to build the interchange. Levis said MDT officials are in negotiations with adjacent landowners.

The department will invite experts from across the country to a workshop in January, aiming to explore ways to get the project built more quickly, identify potential cost savings and minimize impacts on businesses and the public.

MDT also plans to widen portions Custer Avenue and Cedar Street to five lanes and add additional travel lanes on I-15 between the Custer and Cedar interchanges.

Development begins to take shape near interchange

Development begins to take shape near interchange

The new South Helena Interchange is flanked by two mixed-use subdivisions on about 800 acres. The project’s completion likely will spur increased development activity in the area.

Didi Peccia, president of property owner PEC Design-Build, said residential lots have been going fast at the Nob Hill subdivision, a 110-acre parcel of commercial and residential development west of the interstate. About 85 percent of the residential parcels have been sold, and businesses have snapped up about 15 percent of the commercial land.

She said she expects commercial activity to increase after the interchange opens, but she was quick to note interest hasn’t been slow — the developers have been choosy about how the neighborhood will look.

Peccia said she and the rest of the development partnership envision a well-planned, integrated community where residents can live and work in the same neighborhood.

“We’re just trying to determine what the right mix is,” she said. “I’m confident it will all come together in the next year or two.”

On the east side of the interstate, south of Highway 12, the roughly 700-acre Padbury Ranch development is in the early planning stages. Peccia said the land likely will be built out with a mix of commercial and residential uses.