Later this month, the City of Santa Clarita will begin construction on the Newhall Roundabout project in Old Town Newhall.  The roundabout will improve safety and aesthetics, and reduce vehicle emissions at this southern gateway into Old Town Newhall.

A traffic study was prepared for the modern roundabout to be located in Newhall at the currently signalized intersection of Newhall Avenue and Main Street, which compared the operation of the roundabout with the current signalized operation.  This intersection currently operates at Level of Service (LOS) “C” with moderate delay during both the morning and evening peak hours. It is expected that the operation will improve to LOS “A” with minimal delay during both peak hours upon completion of the roundabout. This is due to the fact that modern roundabouts have much less delay than a traditional signalized intersection. Motorists typically do not have to stop like they do at a signalized intersection, but instead can enter, travel through, and exit the roundabout at a reduced speed. The roundabout will also be better able to accommodate projected future increases in traffic volumes than the current traffic signal.

The traffic study also contained a queuing analysis for both the roundabout and the existing traffic signal. The results of this analysis indicated that vehicle queuing or stacking for all legs of the intersection would be much less with a roundabout than with the traffic signal.  Again, this is because motorists generally do not have to stop at a roundabout. The vehicle stacking at this location can be over 400 feet during peak traffic periods with the traffic signal. With the roundabout, it is expected that the maximum queue for any leg of the intersection will be under 200-feet during peak traffic periods. In addition, any queues/stacking due to trains will promptly clear once the train passes. With a roundabout, there are no signals to delay clearing of the intersection.

Click image to enlarge

According to the Insurance Institute for Highway Safety, traffic roundabouts result in:

* 40 percent fewer vehicular collisions

* 75 percent fewer injuries

* 90 percent fewer fatalities

* 45 percent fewer pedestrian collisions

* Fewer starts and stops, less idling

In a study done by Kansas State University, the following was determined about roundabouts:

* Less pollution, less greenhouse gas emissions

* 21 percent reduction in fuel use

* 26 percent reduction in total hydrocarbon emissions

* 19 percent reduction in CO

* 16 percent reduction in NOx

* 21 percent reduction in CO2

In advance of the project, numerous public presentations and meetings were held, including an open house, with area business and property owners, local non-profit agencies, the Old Town Newhall Association, Hart Park and area residents, which included sharing construction plans and traffic simulations and obtaining feedback regarding lane closures, detour plans and signage. Properties will remain accessible to the public during the construction of the roundabout.

The City has collaborated and coordinated all aspects of the project with Los Angeles County, specifically the architect handling the Hart park frontage enhancement for the right-turn pocket at the Hart Park entrance and the direct pedestrian entry from the roundabout to Hart Park.  Both driveways at Hart Park will remain open during the construction of the roundabout and signage will be available to guide motorists.

The anticipated length of the construction is seven to nine months. Signage will be available promoting businesses being open on Main Street during construction and the City will have a Roundabout project construction office located at 24303 Walnut Street, #200.  The phone number is 661- 253-5778.

Andrew Yi is the City of Santa Clarita’s traffic engineer.