Aspects of design - Route 27 over Route 9 interchange improvements, Natick

The following topics summarize some of the more significant aspects of the design that have been discussed as part of the public process to-date.

Table of Contents

Project funding

The Massachusetts Department of Transportation (MassDOT) and The Boston Region Metropolitan Planning Organization (MPO) are committed to the project and the required funding. In the Transportation Improvement Plan (TIP) there is $55 million earmarked for this project. For additional information on the MassDOT Statewide Transportation Improvement Program, please see information on the Federal Fiscal Year (FFY) 2021-2025 Statewide Transportation Improvement Program.

Safety improvements

Project elements to improve safety include:

  • Separated shared use paths will be provided along at least one side of both Route 9 and Route 27 to provide safe, comfortable accommodations for both pedestrians and cyclists. Accessible sidewalks will also be provided throughout the project limits where shared use paths are not proposed.
  • The project will provide improved acceleration/deceleration lanes along Route 9 at the Route 27 interchange. This should reduce the number of crashes by providing more space for exiting/entering vehicles to slow/accelerate outside of the Route 9 mainline traffic.
  • With the implementation of the modified diverging diamond configuration at the interchange, the weaving of entering/exiting vehicles between on and off ramps along Route 9 will be eliminated.
  • The modified diverging diamond configuration reduces the potential for more severe angle type collisions. This is done by removing signalized left turn movements that cross opposing traffic.
  • The roadway geometry for Route 27 on either approach to the bridge(s) includes intentional curvature to slow vehicle travel speeds. Slower travel speeds translate to less severe crashes, should they occur.
  • New rigid concrete barrier will be installed to separate the eastbound and westbound vehicle lanes along Route 9.
  • Addition of steel guardrail or rigid concrete barrier along portions of Route 27 and along the on-ramps and off-ramps.
  • The two new traffic signals at the modified diverging diamond crossovers will have concurrent pedestrian WALK phases within crosswalks that have no exposure to conflicting vehicle movements.
  • Roadway and pedestrian lighting will be included to increase visibility and provide additional safety in low light conditions.

Signalized intersections

The proposed project includes 4 signalized intersections: 2 new installations and 2 existing locations that will be reconfigured/modified.

  • Existing signalized intersections that will include new pedestrian phasing and/or additional approach lanes:
    • Bacon Street
    • 9/27 Exchange Driveway
  • 2 new signalized intersections will be constructed at the “cross-over” locations along Route 27 (where the northbound and southbound travel lanes along Route 27 cross).
  • The four intersections will be coordinated to optimize traffic flow along Route 27 and minimize the occurrence of stopping at multiple traffic signals. Signal timings will be optimized to reduce backups and congestion and improve overall level of service.
  • Each intersection will include pedestrian push buttons to actuate the pedestrian phase for crossing. Pedestrian phasing will consist of exclusive, concurrent and concurrent with leading pedestrian interval.
  • Pedestrian-actuated warning systems are proposed at the on/off ramp crosswalk locations to increase driver awareness and yielding of crossing activity.

Pedestrian and bicycle accommodations

  • A shared use path will be proposed along Route 9 eastbound separated by a grass strip. This path will provide connectivity from the Route 27 bicycle/pedestrian facilities to destinations along Route 9, including the Cochituate Rail Trail as well as the MathWorks campus.
  • A sidewalk is proposed on the north side of Route 9 (adjacent to the westbound travel lanes).
  • A shared use path is also proposed along Route 27 including a high comfort, separated bridge over Route 9 designated exclusively for pedestrian and bicyclist traffic.
  • As previously mentioned, pedestrian actuated signals will be provided at the intersections while pedestrian-actuated warning systems will be proposed at all pedestrian crossings of the Route 9 on/off ramps.

MWRTA bus stops

  • The project will include four new MWRTA bus stops at the interchange of Route 9 and Route 27. There will be a stop along Route 27 northbound, Route 27 southbound, Route 9 westbound and Route 9 eastbound. The bus stops will all be connected via ADA compliant sidewalks or shared use paths.
  • Shelters are anticipated at each of the bus stop locations to increase comfort for patrons.
  • The project team has coordinated with the MWRTA to develop these accommodations and will continue to coordinate with the MWRTA as the design advances.

Impacts to private property

There are areas of the project that require additional Right-of-Way for the roadway improvements. Right-of-Way is publicly owned area reserved for transportation purposes.

If your property, or a portion of it, needs to be acquired, you will be contacted by a representative of the MassDOT Right of Way (ROW) Bureau to arrange a meeting. At the meeting, our representative will provide you with a right-of-way plan showing the impacts to your property and offer an overview of the project. They will also explain the acquisition process, review information relative to the property, and document any concerns you may have.

MassDOT provides uniform and equitable treatment for those whose property is acquired. MassDOT respects fundamental property rights and is committed to treating all property owners with fairness and respect.

Additional information may be found via the MassDOT Right of Way guide for property owners.

Interchange simulations

During the public meetings there has been a concern that the interchange will be too confusing. Admittedly, when viewing a diverging diamond in plan view (i.e., looking down from overhead) the road network looks quite unique compared to most traditional interchanges. With that said, the experience navigating a diverging diamond from a driver’s perspective is far more simplified than one might expect. This is due to the roadway geometry and limited number of decision points for drivers. Also, the signing will be clear for drivers to understand how to get to their desired destination.

To better understand the driver's perspective, a few simulations were created along the proposed project alignment.

This simulation represents a driver's perspective who is travelling along Route 9 westbound and exits to access Route 27 southbound toward Natick Town Center:

This simulation represents a driver's perspective who is travelling along Route 27 southbound and continues through the interchange along Route 27 southbound toward Natick Town Center:

This simulation represents the path a bicyclist or pedestrian would utilize to travel southbound along the proposed shared use path from Rutledge Road, over Route 9 and toward Bacon Street/Natick Town Center:

Lakeshore Road reconfiguration

During the public engagement process for this project, abutters raised concern about the access that the project will provide to Lakeshore Road. Based on the concerns raised during the 2019 public meeting, MassDOT revisited the configuration and developed a new arrangement which will greatly improve and simplify the access.

  • For motorists travelling northbound on Route 27, they will turn left into a dedicated lane within the raised median island where they will approach a STOP sign. After finding an appropriate gap in the southbound Route 27 traffic stream, they will proceed straight to access Lakeshore Road.
  • For motorists travelling southbound on Route 27, they will take a right turn movement onto Lakeshore Road.
  • For motorists leaving Lakeshore Road and heading south on Route 27, they will take a right turn movement after approaching a STOP sign and then finding the appropriate gap in traffic to procced. Once on Route 27 south motorists can then proceed to Route 9 westbound, Route 9 eastbound or continue south on Route 27 to Natick Center.
  • For motorists leaving Lakeshore Road and heading north on Route 27, they will approach a STOP sign at the end of Lakeshore Road and then proceed straight, crossing Route 27 southbound traffic once there is a safe gap to do so. Motorists will then be within a short dedicated lane within a raised median island where they will approach a STOP sign. After finding an appropriate gap in the northbound Route 27 traffic stream, they will take a left turn movement to proceed north on Route 27.
  • A brief traffic simulation can be viewed to help understand how vehicle access will function at Lakeshore Road:

Bacon Street operations

During the public meeting held in June 2021 there was significant discussion regarding the number of lanes heading southbound along Route 27 between Route 9 and the Bacon Street intersection. There were differing opinions shared by the public. Some felt that two southbound lanes would be critical to the success of the project since this approach to Bacon Street often backs up toward Route 9 today. Others felt that two southbound travel lanes would make access to the properties on the west side of Route 27 more difficult since more lanes would need to be considered for lefts into and out of those properties. Based on the analysis completed by the project team, two southbound lanes are recommended along this stretch of Route 27 for a few reasons:

  • By providing two southbound travel lanes the occasional left turning vehicle will not block the through traffic and when there are no left turning vehicles present, that additional travel lane can be utilized to process the through traffic more efficiently, resulting in less queuing back toward Route 9.
  • Providing only one southbound travel lane will result in queuing along Route 27 which will block many of the driveways to access the properties to the west. Simulation has also shown that the queuing has the potential to spill back and impact the function of the interchange.
  • Based on traffic simulation models, the newly proposed traffic signal at the Route 9 eastbound ramps creates ‘gaps’ in the Route 27 traffic stream that do not currently exist. These gaps will allow for adequate opportunity for left turn vehicle movements to and from the properties along the west side of Route 27.
  • Following is a traffic simulation that shows one southbound through travel lane approaching Bacon Street. As seen, the queue will extend north toward Route 9 almost to the interchange.
  • Following is a traffic simulation that shows two southbound travel lanes approaching Bacon Street. This two-lane scenario reduces the amount of queuing along the approach while the inside travel lane at Bacon Street is used for both through movements and the occasional left turn movement. The simulation also shows that there are gaps of traffic flow along Route 27 that will allow left turn movements from the adjacent driveways.

Landscaping elements

  • The project's overall intention is to connect an efficient and safe bridge and intersection redesign with a strong emphasis on bicycle and pedestrian connectivity across Route 9, which has historically been a barrier for the community. South of the interchange, North Main Street leads to downtown Natick while both the elementary and middle schools are located just north of the interchange. The project will provide a high comfort connection for the community with particular emphasis on children walking and bicycling to the schools.
  • Recognizing that comfort for pedestrians and bicyclists can be enhanced by attractive landscaping, plantings are proposed to create the feeling of a naturally vegetated environment throughout the inboard islands of the interchange, along the shared use path and sidewalk environments and as an attractive enrichment to traffic island areas.
  • The project is not intending to present formal landscaping as a civic park or large space for gathering or recreation. The project landscaping approach looks to utilize open space to the extent practicable in the form of low maintenance plantings of wooded, shady, and meadow landscapes that would appear more natural and designed to fit within the limited maintenance capabilities of MassDOT in this area. Native plant species for shade, the environmental value of habitat, and meadow spaces for grasses and wildflowers are emphasized in the design.
  • There will be opportunity for private entities to ‘adopt’ locations within the interchange for more ornamental maintained plantings. Parties that are interested in ‘adopting’ a landscape area within the interchange are encouraged to contact MassDOT using the project contact information provided on this page.

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