Conceptual Layout

The intersection of Elms Road and Miller Road was included in the early preliminary engineering phase with support from the City of Swartz Creek due to intersection operations and safety concerns. This intersection is included in the 153 intersections that passed the skim analysis for experiencing crashes correctable by a roundabout and is a secondary analysis Tier One intersection.

During the skim analysis, it was observed that there were 14 angle crashes and 6 head on left turn crashes over the 5-year period. These crashes resulted 0 fatalities, 3 type A injuries, 6 type B injuries, and 13 type C injuries at the intersection.

The intersection of Elms Road and Miller Road is a traffic signal-controlled intersection. Elms Road is a north/south roadway and is primarily two-lanes with a single-lane in each direction. At Miller Road, the approaches of Elms Road include one exclusive left-turn lane, one exclusive through lane, and one shared through/right-turn lane. Miller Road is an east/west road and has four lanes (two lanes in each direction) east of the project location and three lanes (one lane in each direction and center left-turn lane) west of the project location. At Elms Road, the approaches of Miller Road are one exclusive leftturn lane, one exclusive through lane, and one shared through/right-turn lane. There are pedestrian crossings at all legs of the intersection.

In the northwest quadrant is a Kentucky Fried Chicken restaurant. The northeast quadrant is a McDonalds restaurant. An O’Reilly Auto Parts store is present in the southeast quadrant. There is an office building in the southwest quadrant. There are overhead utilities present on the south, west, and north legs of the intersection. At ground level, there is a fire hydrant in southwest quadrant. There is also a base mounted utility controller in the southeast quadrant.

An operational analysis of the no-build condition was completed for the intersection using the 2045 forecast traffic volumes. The results of the analysis for the future no-build condition reveals all approaches and movements of the intersection operate at LOS C during the AM and PM peak hours.

The 95th percentile queue lengths were reviewed at the intersection and the results showed all approaches experienced a maximum queue length of 126 feet (8 vehicles) during the AM peak hour and 150 feet (9 vehicles) during the PM peak hour.

The operational results for future no-build conditions are presented in the table below.

The proposed roundabout configuration for the intersection of Elms Road and Miller Road is a single lane circulating with a single-lane approach for northbound and southbound Elms Road and a single lane with a right-turn bypass lane for eastbound and westbound Miller Road. The proposed single-lane roundabout configuration will not fit inside the existing right-of-way. Based on the concept design, additional right-of-way may be required in all four quadrants. The inscribed circle diameter would be 130 feet. The driveway configuration for the existing office building in the southwest quadrant should be investigated due to the existing driveways closeness to the proposed right-turn bypass lane for the roundabout entry/exit radius.

An operational analysis for the single lane roundabout (build) with eastbound/westbound right-turn bypass lane condition was completed for the intersection using 2045 forecast traffic volumes. The results of the analysis for the roundabout (build) condition reveals all approaches and movements of the intersection operate at LOS B or better during the AM and PM peak hours.

The 95th percentile queue lengths were reviewed at the intersection and the results showed all approaches experienced a maximum queue length of two (2) vehicles during the AM peak hour and six (6) vehicles during the PM peak hour.

The operational results for future roundabout (build) conditions are shown in the table below.

A roundabout appears feasible at this location, assuming the City of Swartz Creek can acquire the limited right-of-way that may be needed.

Opinion of probable cost was developed for a double-lane roundabout. The total probable cost is $2.32 million in year 2025 dollars. The probable cost includes a 20 percent contingency and 3 percent inflation. Not included in this fee are the potential costs to relocate any utilities to accommodate the proposed layout.

Potential funding sources for this improvement could include regular road improvement funding, safety funds, or an earmark. A TOR was computed with a result of 7.06.

For a complete breakdown of the estimate please review the full report below.