Utah Department of Transportation officials presented the Helper council members with updated plans for the interchange at U.S. Highway 6 and Main Street in the city last Thursday.
Adjustments to the plans were made by Stanley Consultants, the project designer.
Previous plans for the interchange had resulted in higher than expected costs. As a result, the transportation department has scaled back the plans.
The result is an interchange that will span a shorter distance, but be scalable for expansion in the future as traffic warrants and funding permits.
One of the most significant changes is the elimination of grade separations.
Original plans called for the separation of the two lanes of travel on the highway.
The revised plans leave the lanes where they presently exist. This will save on the cost of constructing new travel lanes.
Another alteration is shortening the length of the exit and entrance ramps.
Original plans called for a change that would affect more than a quarter mile in each direction.
The adjusted plans reduce that distance by shortening the ramps.
The grade of the revised ramps is 3 percent on the north side of the interchange and 5 percent on the south side.
Those grades presented an issue regarding illumination of the road.
The original plans had been a shallow enough grade that headlights would be adequate to light the road in front of cars.
The steeper grade of the revised plans will not be illuminated by headlights.
As a result, project designers have added lighting to the project.
The lights will be shielded directional lights that will limit light pollution.
With the shorter ramps, roads both north and south will be more accessible than under original plans.
For instance, when the interchange was first designed, Martin Road and the end of north Main Street by Workman's Market would only be accessible from one direction of U.S. Highway 6.
In addition, Martin Road was planned to dead end at U.S. Highway 6.
Under the revised plans, Martin Road will be accessible from westbound Highway 6 only. Cars exiting Martin Road onto the highway will be able to turn both left and right onto the highway. Project designers explained that eastbound traffic will not be able to safely turn left onto Martin Road. The result will be similar to the intersection of Poplar Street and Highway 6. the difference will be that no concrete barriers will be necessary at Martin Road.
At Workman's Market, eastbound highway traffic will be able to turn right. And traffic will be able to turn right from North Main Street to eastbound Highway 6. There will be no left turn to or from Highway 6 at the intersection.
Another modification to the design was leaving the speed through Helper at 55 mph. Original plans had called for an increase to 65 mph. However, with the revisions of the interchange and neighboring intersection, the speed must be left at 55 mph through Helper.
In order to accommodate the possible expansion of the highway, the bridge at North Main will be constructed with the footings and pilings for a four line highway to pass under it. Only two lanes will run under the bridge after it is constructed. But by building the bridge with adequate structural support for two additional lanes, UDOT leaves open the possibility of expanding to four lanes in the future.
In addition, space for two additional lanes will be allowed between travel lanes and the exit and entrance ramps.
Utilities that currently run next tot he highway will be moved as necessary. In addition a water and sewer line for Price River Water Improvement District and two water conveyance lines for Price will be affected. When Price replaced the lines UDOT asked that they not replace the portion will be affected by the interchange construction. That portion as well as lines operated by PRWID will be replaced by construction crews once the project is finalized.
UDOT officials and project planners estimated that the final design will go to bid in February 2006. Construction could begin as early as April, with construction taking an estimated 15 months to complete. The completed interchange could be finished by fall 2007. Delays could push that into early 2008.
One of the requirements for the contractor who is awarded the id will be to keep two lanes of traffic on Highway 6 and at least one lane of North Main crossing the highway open at all times. The only times the highway will close will be at night when the beams of the bridge are set.