Click here to view a PDF of the traffic review letter
Dear Mr. Callahan:
I have prepared this letter as a follow up to our work last fall and in response to your request for a summary of that review in relation to the proposed apartment development in Scituate and in particular, the potential access points. As you may be aware, Green International Affiliates, Inc. (Green) is a multi-‐disciplined civil, structural and transportation engineering firm located in Westford, Massachusetts. Green’s Transportation Engineering Division provides a broad range of roadway and traffic engineering services, including municipal and state roadway and highway design, traffic signal design, pedestrian and bicycle facilities and traffic impact studies. These services are performed for a number of state agencies, municipalities and private sector clients. Green’s Transportation Planning Department conducts studies to evaluate and create plans that accommodate the safe, efficient movement of people and goods. The studies comprise the evaluation, assessment, management and design of transportation facilities and services to develop balanced, sustainable solutions to meet community needs.
It is our current understanding that the proposed building program consists of up to 252 apartment units. The site is within an area generally bounded by Booth Hill Road, Clapp Road, Mann Lot Road and Route 3A. Based on the property boundaries and the current development concept plan, access would be directly out to Booth Hill Road in the vicinity of 133 Booth Hill Road where there is property frontage. There may be the potential to gain access to Route 3A as an alternative plan because while the property does not connect with Route 3A, it does abut the town owned land that has frontage on Route 3A. If an agreement between the town and the owner were reached, this alternative access plan would be facilitated.
The purpose of Green’s preliminary review was to become familiar with the roadway network in the project area, review the current access plan for the project and additionally, and make an assessment regarding the potential for accessing Route 3A directly as an alternative to Booth Hill Road. In completing this preliminary review, a site visit was conducted on October 2, 2014. During the site visit, the geometry and traffic control of the roadways and intersections were noted and the sight distances relative to the potential site access drive locations on both Route 3A or Booth Hill Road were reviewed. Also, the land uses in the general area activity that could influence site traffic patterns were identified. As we have discussed, the project will require more detailed traffic studies as it advances through the permitting process, however, this preliminary review confirms the feasibility of either access location.
Booth Hill Road is a two lane road that provides access to residential properties that either abut the street directly or through minor roadways that connect with Booth Hill Road. The pavement is approximately 20 to 22 feet in width and the characteristics of the geometry could be characterized as having gentle horizontal and vertical changes in alignment. Posted speeds of 30 mph were noted. Based on the site visit, it appears that Booth Hill Road is a low to moderate volume roadway. It intersects with Route 3A, a major north-‐south highway, approximately 1,250 feet east of the potential site access. West of Route 3A, land uses are residential in nature. East of route 3A, the street provides a connection to the commuter rail station. The intersection is a 4-‐way intersection with STOP control on the minor street approaches. A flashing beacon on a mast arm is located at the intersection that provides motorist warning for Route 3A traffic for more than 500 feet. Booth Hill Road also intersects with Clapp Road to the west of the site where it forms a ‘T’ type intersection. STOP control is on the Booth Hill Road approach. In general, good visibility exists at this intersection. Clapp Road provides a secondary route towards the southwest and to the north.
Route 3A is a major north-‐south route in southeastern Massachusetts and comes under the jurisdiction of the Massachusetts Department of Transportation (MassDOT). This two lane route has a pavement width of approximately 28 to 32 feet and importantly has a public right of way in excess of 60 feet. The available right of way provides flexibility in relation to access design. In terms of sight distance based on AASHTO1 criteria, a minimum of 405 feet would be needed to meet the criteria for the posted speed of 50 miles per hour (mph). The Town’s new public safety complex is planned to be constructed near the intersection of Route 3A and Mann Lot Road. Based on MassDOT databases, it is estimated that Route 3A in the project area experiences daily volumes of in the range of 15,000 vehicles. Based on the roadway design and it current volume levels, additional traffic can be accommodated.
Under the current proposed plan, access for the site would be provided by a site drive located on Booth Hill Road approximately 1,250 feet west of Route 3A. A preliminary review of the location indicated that safe sight distance criteria could be satisfied on Booth Hill Road. The site drive location would be separated from existing subdivision roads by 400 to 600 feet, which is more than acceptable. Based on the apparent low volume on Booth Hill Road, traffic would be expected to be able to easily enter and exit the site. Given the location of the proposed drive on Booth Hill Road, one could expect a reasonably high portion of site trips to use Booth Hill Road and Clapp Road in making their respective trips.
While the Booth Hill Road access is feasible, the Route 3A alternative offers some potential advantages over the Booth Hill Road access. The location of the site drive on Route 3A would far exceed the minimum distance criteria resulting in more than adequate safe stopping sight distance being available. The wide layout allows the flexibility in access design such as turning lanes. The width of the public right of way on Booth Hill Road is substantially less than that on Route 3A which limits the ability of any pavement widening for potential turn lanes. With the site drive connecting directly to Route 3A, there would likely be less tendency for site traffic to use the local streets such as Booth Hill Road and Clapp Road to reach various destinations to the north or south. Although there would be moderately high peak hour delays experienced by motorists exiting the new site drive onto Route 3A (specifically related to left turn movements), this would be similar to the delay that is and will continue to be experienced for left turn movements from existing driveways and intersecting roadways onto Route 3A such as Booth Hill Road. Traffic is expected to be able to enter the site safely and with minimal vehicle delays. With the ability to provide for turn lanes on Route 3A, the project access would have minimal impact to Route 3A mainline traffic flow. With the new drive and the major safety complex to be located just to the south, it is also possible that overall travel speeds along this particular section of Route 3A could be somewhat lowered.
Based on this preliminary review, the potential access for this proposed development directly out to Route 3A would be a better alternative than the Booth Hill Road access plan for a number of reasons. These include:
- With the relatively large project and resulting traffic generation, it encourages traffic to remain on Route 3A – the major route in the area,
- The Route 3A access location as well as the Booth Hill Road location would exceed minimum safe sight distances available with an optimum driveway location,
- With the Route 3A site drive, there is more flexibility in terms of site access design given the wide Route 3A right of way that can accommodate left or right turn lanes at the site access drive if deemed desirable in subsequent detailed studies as well as the ability to more easily provide a multiple lane approach to Route 3A, and
- There is less direct impact on the existing residential areas along Booth Hill Road with the alternative that has direct access to Route 3A.
Again, more detailed traffic studies need to be conducted as the project moves forward in the permitting process to determine the exact geometric design and traffic control features. Opportunities also exist under either project access alternative to develop a reasonable transportation mitigation and management plan for the development.
If you have any questions or want to discuss project access in more depth at this point, do not hesitate to contact me at 978-‐923-‐0400.
Very truly yours,
GREEN INTERNATIONAL AFFILIATES, INC.
William J Scully
William J. Scully, P.E.
Director of Transportation Planning
Understanding the Clapp Road Land Swap 