They slow traffic down.
They keep traffic moving.
They make it easier to cross streets and enhance safety near schools and parks
They discourage through traffic in neighborhoods.
They avoid traffic signals that can cost as much as $500,000 per intersection.
In short, roundabouts could be the answer to avoiding a number of future traffic problems in Manteca.
Manteca now has four roundabouts in place — all south of the 120 Bypass — with more on the way.
This year may see the building of the most high-profile roundabout yet.
Trumark Homes is breaking ground in the coming months on 492 homes on 122 acres snuggled against the northeast quadrant of the Louise Avenue overcrossing west of Cottage Avenue.
Trumark is being required to place a roundabout in Louise Avenue about midway between the Highway 99 overcrossing and Cottage Avenue where the main entrance to the subdivision will align with the existing Felice Way that accesses the 99-home Rodoni Estates to the south.
The basic functional design will be similar to the roundabout on four-lane 11th Street just west of Interstate 5 where it intersects with West Gantline Road/Kasson Road on the way to Tracy. Two lanes of eastbound and westbound Louise will wrap around the landscaped roundabout. At the same time Felice Way will have one travel lane in each direction feed into the roundabout. Typically roundabouts have yield signs and not stop signs.
In order to make to work, Louise Avenue will swing slightly to the north to accommodate the roundabout.
Pedestrian crossings will be away from the roundabout on Louise Avenue as well as on the entrance road to the development that aligns with Felice Way.
The new subdivision will have only two access points for the seven distinct neighborhoods Trumark Homes is planning — the one at the roundabout on Louise Avenue and the other on Southland Road.
The roundabout is in lieu of placing traffic signals at the intersection with the entrance that was originally approved as Shadowbrook Estates.
Roundabouts — or traffic circles — are viewed by the city as a way of addressing four major traffic concerns including how to:
uimprove the safety of pedestrians especially crossing at intersections adjacent to neighborhood parks and schools.
ukeep traffic moving and avoid costly traffic signals where collector streets meet and — in some cases — where an arterial and collector street cross.
ureduce traffic speed.
uimprove air quality by eliminating stop signs which in turn reduces increased air pollution created by stop and go movements.
Manteca has three roundabouts located within a block north of the Woodward Avenue corridor east of South Main Street. Two are at the edge of the Tesoro Park neighborhood including one that is adjacent to a park. There is much larger roundabout with an acre park in the middle of Buena Vista Drive north of Woodward Avenue.
There is a fourth roundabout on Woodward Avenue at Al Fonseca Lane with a fifth that will be built soon at Woodward at Tinnin Road that currently only has plastic markers and uses stop signs.
There is also a roundabout on private property within the Promenade Shops at Orchard Valley.
Seven more are already approved to go on or near Woodward Avenue as part of the 1,450-home Trails at Manteca envisioned on the western end of Woodward Avenue. Two of the seven cul-de-sacs will be at access streets intersection with Woodward Avenue.
Virtually every new neighborhood in the planning process has a requirement for roundabouts either adjacent to future schools or parks or deployed in a manner to slow traffic on the main access street. All roundabouts built in new neighborhoods as a condition of development are landscaped
The roundabouts already in place reflect three different strategies. The ones in the Tesoro neighborhood are designed to slow traffic down near schools and parks that have heavy foot traffic. The acre roundabout on Buena Vista Drive is designed to discourage future through traffic from the between Atherton Drive and Woodward Avenue now that the gap on Atherton between South Main Street and Wellington Avenue has been completed. The area along Atherton Drive is zoned commercial and is expected to lure heavy traffic volumes. The one on Woodward Avenue was placed to slow traffic down without forcing vehicles to come to a stop.
The use of roundabouts allows the city to keep traffic moving while slowing it down enough to allow access from connector streets. It also would also go toward meeting a mandate of the San Joaquin Valley Air Pollution Control District to reduce vehicle idling. The more time vehicles have to stop at traffic signals or stop signs, the less efficiently they burn carbon-based fuel which in turn impacts air quality. Idling vehicles are a major source of valley air pollution.
Roundabouts also save cities considerable amount of money and can reduce the cost of new homes. That is accomplished by deploying roundabouts instead of traffic signals wherever feasible on moderately traveled streets. Not only does that save $500,000 in upfront cost for signals but it reduces ongoing maintenance costs. The reduced development costs also can translate into slightly lower housing prices. The cost of neighborhood infrastructure including improvement sot nearby arterial streets is collapsed into the price of a new home.
Ripon and Lathrop also make use of roundabouts.
To contact Dennis Wyatt, e-mail email@example.com