Tamal Vista Boulevard Complete Streets and Madera Roundabout Project
The Town of Corte Madera is in the design phase for a complete streets improvement project on Tamal Vista Boulevard between Fifer Avenue and Madera Boulevard, including a modern roundabout at the Madera Boulevard intersection. The project is intended to enhance the safety for vehicles, bicyclists and pedestrians while also providing enhancements to traffic flow without encouraging speeding.
What is a Roundabout?
A roundabout is a circular intersection where drivers travel counterclockwise around a center raised island. The right-of-way associated with a roundabout is clear – drivers yield entry to vehicles already in the roundabout and exit at their desired street. Additionally the center island slows vehicular speeds through the horizontal deflection required to pass through the intersection. While roundabouts (sometimes known as rotaries) are much more common on the East Coast, in Europe, and in Australasian countries such as Australia and New Zealand, they are relatively new to California and the West Coast. Nonetheless, there are many benefits to roundabouts in many urban contexts, and which are summarized below. Video: How a Roundabout Works
What are the Benefits of Roundabouts?
Roundabouts can provide lasting benefits and value in many ways, and which has been quantified through research from roundabout projects from around the world.
Improve Safety – Roundabouts reduce injury collisions by 75% at intersections where stop signs or traffic signals were previously used for traffic control. More specifically, studies by the Federal Highway Administration (FHWA) and the Insurance Institute for Highway Safety (IIHS) indicate that roundabouts typically achieve:
37% reduction in overall collisions
75% reduction in injury collisions
90% reduction in fatality collisions
40% reduction in pedestrian collisions
There are several reasons for the reduction in the likelihood and severity of collisions, including:
Fewer conflict points. At a signalized intersection there are 32 places where traffic can potentially cross paths. This greatly increases the potential for collisions. By contrast, there are only 8 total conflict points at an equivalent roundabout which helps to significantly reduce the opportunity for collisions. Importantly, roundabouts reduce the severity of collisions since the type of conflicts are the same-direction variety. Collisions of this type greatly reduce the likelihood of injury or fatality. The opportunities for a T-bone or head-on collision is reduced to zero in a roundabout.
Low Travel Speeds – Roundabouts have a slowing effect on drivers since they must slow down and yield to traffic before entering the roundabout and must deflect around the center island to pass through the intersection. According to the FHWA, travel speeds are typically 15-25 mph throughout a roundabout.
Clarity of Right-of-Way – unlike in a complex stop sign controlled intersection with multiple lanes of traffic such as at Tamal Vista Boulevard/Madera Boulevard, the right-of-way at a roundabout is clear; drivers only need to yield to drivers in the roundabout rather than considering drivers at the six other approaches at this specific intersection.
Reduce Congestion – with no stop signs or traffic signals, roundabouts promote a continuous flow of traffic that reduces congestion and delay. Since drivers are only required to yield, the intersection can handle more traffic in the same amount of time. IIHS studies of roundabouts in three states found that roundabouts contribute to an 89% reduction in delays and a 56% reduction in vehicle stops.
Improve Aesthetics – Roundabouts typically reduce the amount of asphalt in an intersection and offer opportunities for low landscaping and other neighborhood gateway treatments.
Save Money – As compared to a traffic signal, the cost difference to construct and maintain a roundabout is significant. Roundabouts eliminate the need for hardware, maintenance and electrical costs. Importantly, roundabouts can continue to operate during power outages.
The memo discusses the general benefits of a modern roundabout and also describes the specific benefits that a roundabout would provide to the intersection at Madera & Tamal Vista, which include improved pedestrian and bicycle safety and comfort, reduction in traffic congestion, enhanced neighborhood livability, and more environmentally friendly. The document also compares the roundabout to a potential enhanced 4-way stop sign-controlled intersection and discusses some of the pros/cons of each of those alternatives.
The rendering shows an updated schematic of the proposed roundabout design, which has been shifted approximately 8 feet closer to the Town Center Shopping Mall, and illustrates some potential visual enhancements such as landscaping and decorative hardscapes, and updates the geometrics to show the various enhanced vehicular, bicycle and pedestrian facilities. The roundabout’s design continues to be refined and minor changes could result.
In addition, based on public input the Town has also reached out to W-Trans, a third party transportation engineering consulting firm, to perform an independent peer review of the Parisi Transportation Consulting design to further assess and determine the applicability of a roundabout at this intersection. The results of their analysis will be shared with the public and is anticipated to be available the week of March 30th.
Public Outreach Summary:
The project has been in development since 2018 and has been discussed at several meetings where the public has been invited to participate in the project and fiscal planning. Below is a summary of the public discussions including links to staff reports and recorded meetings:
The roundabout concept at Madera and Tamal Vista was first considered in 2015 after a modified modern roundabout was recommended along Madera Boulevard at the Town Center and Corte Madera Inn driveways (Draft Recirculated Environmental Impact Report). Either roundabout could stand on their own and provide substantial multimodal benefits. The modified roundabout at Town Center/Corte Madera Inn was accepted by the Town for implementation as part of the Corte Madera Inn Rebuild. Either or both roundabouts would improve traffic flow and safety and enhance pedestrian and bicycle safety, citing that a roundabout “would substantially reduce potential conflicts – under current and future conditions.” Figure B3 provides you with a visual representation of this concept. Following its inception, many Madera roundabout discussions continued over the years at several Bicycle and Pedestrian Advisory Committee and Town Council Meetings summarized below. To view the full Corte Madera Inn project page use this link: https://www.townofcortemadera.org/531/Corte-Madera-Inn-Rebuild-Project.
August 22, 2019 Neighborhood Meeting (Council Crest & Tamal Vista Residents)
Approximately 30 residents were invited and about half were in attendance. The focus of this meeting was to discuss the 2019 Sewer Rehabilitation project on Council Crest and Tamal Vista Boulevard and how it was tied to the future paving on those streets. The Tamal Vista Complete Streets and Madera Roundabout project were also introduced as upcoming projects in summer 2020 to be aware of.
June 4, 2019 Town Council Meeting Agenda (see item 6b) Staff Report
This is item 6B from the Agenda. This is included because this is the annual discussion of which projects to include in the Capital Improvement Program, which Council adopts. This project is listed as an item under "Multimodal Transportation" in the CIP Attachment (p.9 of the attachment) Video
December 13, 2018 Bicycle & Pedestrian Advisory Committee Meeting Agenda
Item 5D discusses the Tamal Vista project and roundabout at Madera Video
June 21, 2018 Bicycle & Pedestrian Advisory Committee Meeting Agenda
Item 7A discusses the Tamal Vista project and roundabout at Madera Video
June 19, 2018 Town Council Meeting Agenda
This is item 5.I.i from the Agenda. This is included because this is the annual discussion of which projects to include in the Capital Improvement Program, which Council adopts. This project is listed as an item under "Multimodal Transportation" in the CIP Attachment (p.9 of attachment 2) Video
Upcoming Outreach Events:
Nothing scheduled at this time.
Preliminary Estimate (As of January 2019):
Tamal Vista Complete Streets (Fifer Ave. to Madera Blvd.) - $2.1M
Madera Roundabout - $900K Council Crest Resurfacing - $170K
Combined Preliminary Estimate = $3.17M(*)
*Engineer’s Estimate to be finalized as part of construction bid documents in early spring 2020’
Anticipated Construction Schedule:
May 2020 to November 2020 (*)
*Construction between Fifer Avenue and Wornum Drive to be prioritized between June and end of August to coincide with school break