SR 05:293 - Laserfiche WebLink

Staff fmds that the roundabouts appear to result in the least congestion and ideal travel speeds near the future school site along Vineyard Avenue. With the school entrance on the south end of the school site adjacent to the Old Vineyard multi-purpose trail, there are no school-related pedestrian or bike issues at the roundabouts. Vineyard Avenue would have to be widened significantly east of the intersection, and increased bus and carpool use would be necessary from Ruby Hill to the school for a traffic signal to work effectively at this intersection. The need for the traffic signal in the Specific Plan and the roundabouts that were built to replace the signal were primarily triggered by plans to build an Elementary School on this site. If pending court decisions result in the school not being built and the land use changes such that significantly less peak hour traffic is generated by the site, the need for the roundabouts would need to be re-evaluated. If the school site were converted to low density housing, 1- way stop sign control would probably suffice at each intersection in place of the roundabouts as traffic volumes would not be sufficient to meet the requirements for installation of a traffic signal. Without the school, another option would be to build a road within the tract that links the two side streets. This would allow one of the intersections to be eliminated, and concentrate all residential traffic at one signalized intersection along Vineyard Avenue. Vineyard A venue would have to be widened to create left and right turn pockets Some residents have complained about the need to slow down at the roundabouts while the school has not been built and little traffic is using the side streets. There have also been incidents where large trucks have become stuck in the roundabouts while trying to make u- turns. The residents using the side streets have complained that Vineyard Avenue traffic fails to yield to them properly. A few vehicles have run off the road at the roundabouts due to inattention, or driving under the influence. Staff discussed making the roundabouts 20 feet larger during the design of the project. However larger roundabouts would have taken some land away from the school site and properties on the other two corners. Large, high speed roadway circles known as rotaries were not considered at these locations. Not only would they have required significantly more land, but studies show that the high speeds lead to more serious collisions. The federal design guidelines for roundabouts were specifically intended to increase safety by reducing the size of circular intersections, and many East Coast rotaries have been replaced by much smaller roundabouts for these reasons. Overall, roundabouts tend to improve traffic safety by virtually eliminating serious right-angle collisions. It is not uncommon for the main street traffic at roundabouts to fail to yield to side street traffic where side street traffic volumes are very low. With the grading of the surrounding land for home construction, and the eventual construction of the elementary school, this problem should be temporary. The roundabouts are not a perfect traffic control device and have their own limitations, just as do stop signs and traffic signals. But, with the school and homes planned in the Specific Plan area, the roundabouts are the best way to control traffic circulation and speeds near the school unless the City decides to significantly SR:05:293 Page 5 of 8