Consider Sight Triangle Concerns at Alpine Drive and Puma Street

Staff received a concern from a resident about visibility at the Alpine Drive - Puma street intersection.  Puma Street was paved in 2011 and provides a connection from the western extension of Bunker Lake Boulevard to Alpine Drive.  The concern states that north bound traffic on Puma cannot see eastbound traffic on Alpine Drive in time to safely enter or cross Alpine Drive.

Puma Street was gravel and served one residence prior to being paved.  It will be an important access route for Legacy Christian School and the other developments proposed for the intersection of Bunker Lake Boulevard and Puma Street. Clear sight lines at the intersection of Alpine Drive and Puma street is critical for the safety of the traveling public.

The resident has been notified that this case will be discussed at the Public Works Committee meeting.

Staff has visited the site and observed the site distances from Puma Street.  Staff also gathered survey data west of Puma Street and south of Alpine Drive.  The Alpine Drive alignment curves south just west of Puma Street.  The road rises from west to east in this same area.  There is a row of pine trees in the right of way that blocks vision of oncoming vehicles.



Staff performed a sight line analysis using the topographic data obtained.  The sight line crosses the northern edge of the property west of Puma Street.  The analysis indicated that excavation of the south boulevard of Alpine Drive could provide adequate site distance at this intersection.  The excavation will require reshaping a portion of the private property which is currently used for crops. The excavation will require a permanent easement from the adjacent property owner for the sight triangle and and a temporary easement for grading and excavation.   The proposed grading used a 1 percent slope from the top of curb to south of the sight line then a 10 percent slope to blend into existing grades so that the area could continue to be used for crops.    There is an area where the sight line and the proposed grading are at the same elevation.  Vegetation and weed growth could block the sight line, mowing will be a regular requirement for this stretch of boulevard.

An exhibit showing the area and the proposed grading is attached to the case.

The funding source for this project is the PIR Fund.  The estimated costs for this is $42,300, broken down as site work $35,400 and easements $6,900.

Staff recommends entering into negotiations with the land owner for acquisition of the necessary easements.  The site work could be issued as a request for quote after the easements are acquired.

Motion to recommend that the City Council authorize entering into negotiations with the land owner for the necessary easements to lower the boulevard south of Alpine Drive and  west of Puma Street to provide better sight distance.