by Dave DeMars
news@thenewsleaders.com
In a joint work session, the Sartell City Council and the Sartell–St. Stephen School Board met Jan. 9 in the school-district board room to hear and discuss information on the Pinecone Road Project. The project is considered necessary as a result of District 748 building a new high school, which is expected to result in a much heavier traffic flow on Pinecone Road.
At the meeting, Mike Kotila and Jon Halter of SEH, the city engineering firm, presented the time lines and problems for discussion.
Halter began by laying out the project which will include the reconstruction of Pinecone Road from 15th Street N. near Celebration Lutheran Church to 35th Street N. The project is in the very early stages of development. More planning meetings will be held as the project moves forward.
A rough time line includes the feasibility study in the spring of 2017, a preliminary assessment of the project scope in spring/summer of 2017, survey design work in the late summer and fall of 2017, right-of-way acquisitions in the fall of 2017, project bidding in the winter of 2017 and finally the start of construction in the spring of 2018, which would continue through the summer and into fall.
Halter noted there has been some discussion about improvements needed on 27th Street N. as well, but that is likely to be done in 2019. The entire streets project is in response to the building of a new high school, which is slated to open in the fall of 2019, so it’s hoped the street construction work will be completed by that time.
At issue are two intersections on Pinecone Road; at 27th Street N. and at 35th Street N. The problem is an entrance to the new-school site located between the two intersections. With the increased amount of traffic that will be created by a new high school, some new street designs have to be created to handle the safety issues that will result.
“We’re talking about magnitudes of 500 to 600 cars per hour during peak hours in both directions,” Kotila said.
There are several solutions to the problem, Kotila said, but three that seem to be best in terms of safety, traffic flow and cost of construction. Part of the solution will include making Pinecone Road a three-lane street from 15th Street N. to 40th Street N. with a center turning lane. That would create a smoother traffic flow, but it does not address the entrance problem between 27th and 35th streets N.
Kotila said the project plan has to consider performance that includes smooth traffic flow and the safety of drivers and pedestrians along the way, access points for both the high-school and a residential development in the area, and access management. Access-management guidelines require major intersections to be at least a half-mile apart with minor access at quarter-mile intervals. A final caveat emphasized the need to minimize private accesses.
There are several traffic-management tools available to road engineers, including the use of stop signs (both two-way and four-way), the use of stop lights, the use of roundabouts and the use of three-fourths limited-access turn lanes (sometimes referred to as a pork-chop turn). Each of those has its good points and negatives, Kotila said. Stop signs are inexpensive and easy to maintain. People are used to obeying them. But during periods of high traffic volume, they can cause poor traffic flow and result in accidents. Much the same can be said for stop lights, but they have another unintended consequence with drivers trying to beat the red light and speeding through, sometimes causing accidents.
The first option presented was the roundabout. Roundabouts are by far the safest option since they cause a deceleration in speed while at the same time facilitating the smooth movement of traffic. The negatives with roundabouts are their cost to build and a public misperception they cause accidents. Additionally, a roundabout between 27th and 35th streets N. would impede traffic flow in the summer, a time when slower traffic would not be of great importance to aid traffic management. Roundabouts are hands-down the safest and most effective of the traffic management options, according to traffic officials. They are also among the more expensive.
“MNDOT (Minnesota Department of Transportation) looked at all roundabouts statewide, and they found (during) the last 10 years, no serious injuries or fatalities occurred at roundabouts,” Kotila said. “A roundabout when compared to a traffic signal offers a 78-percent reduction in severe traffic crashes and a 48-percent reduction in all crashes.”
Because of the location of the bus-loading and unloading chute, all buses coming from the south would proceed through the roundabouts on 27th Street N. and 35th St. N. to access the loading and unloading chutes on school property Kotila said. They would then exit going back through the roundabout on 35th Street N., heading either north or south to make student drops.
A second option for traffic management involved the use of three stop lights; one at 27th, another at 35th, with a third located at the school access midway between the two intersections. Kotila said the positives are the flow of traffic, some control and the fact during the summer months, the stop light located mid-way between the intersections could be turned off. The negative was that speed would likely be increased making it less safe. Because of specific state guidelines for placement of stop lights, there was also a question as to whether the state would grant traffic-signal warrants or permission to place the signals as described at the high-school entrance.
A third option involved a combination of roundabouts at 27th and 35th with a three-fourths limited-access turn lane between the two roundabouts, which would allow access onto the school property. The negative Kotila pointed out was that, in effect, it made Pinecone Road’s southbound exit a one way.
Drivers going north could exit onto school property, but southbound drivers exiting the property would need to go down to the roundabout at 27th in order to reverse directions and head north. From a safety standpoint, Kotila said the three-fourths access would eliminate the two most dangerous hazards: the left turn out and the crossing-traffic movement.
“Forty-four percent of intersection crashes are of those two types,” Kotila said. “That’s a significant opportunity to avoid those types of crashes.”
The center three-fourths limited access does not impede drivers during non-school time, Kotila said, but in conjunction with the two roundabouts does slow traffic flow while not impeding it completely.
Kotila referenced the speed problem facing the community of Northfield where they are trying to address a very similar issue of speed after the fact by using other tools to control the speed of drivers.
“What they don’t have is the opportunity to put in a roundabout because they have already finished their reconstruction,” Kotila said. “They are looking at $1.5 million to plop in a roundabout, and that is pretty hard to do.”
Kotila said what is being attempted is to be proactive in the planning approach so the difficulties faced in Northfield do not occur in Sartell.
Sartell Superintendent Jeff Schwiebert points to the roundabout at 27th Street N. and its possible location in relation to the proposed new high school.
Mike Kotila of SEH listens carefully to an audience question dealing with his presentation on the use of roundabouts to control traffic speed around a new high school.
Mike Kotila explains how the three-fourths limited-access turn lane would work in conjunction with roundabouts on 27th and 35th streets N. The three-fourths limited access turn lane would allow those exiting from school to only turn south toward the 27th Street N. roundabout.
Jon Halter of SEH kicks off the joint-study session on the Pinecone Road Project. Members of the Sartell City Council and the Sartell–St. Stephen School Board gathered to hear proposals and options related to traffic management on Pinecone Road once a new high school opens in 2019.
