Old South Road at Fairgrounds Road Intersection

Old South Road/Fairgrounds Road Intersection


The purpose of this project is to utilize Town of Nantucket’s Complete Streets Policy (PDF) and the 2006 Massachusetts Highway Department’s Project Development and Design Guide and other Highway Division standards and criteria to design and construct a modern roundabout at this location, as recommended in the Nantucket Master Plan and the NP&EDC’s Regional Transportation

This is an unsignalized 'T' intersection with three single lane approaches with the Fairgrounds northbound approach operating under a stop sign control. It should be noted that a short (approximately 60 feet in length) and unmarked portion of the Fairgrounds single lane approach is very wide and functions as a right turn lane. This intersection is also located in a densely settled part of the island, the Town Overlay District, populated mostly by year round residents. Congestion is experienced throughout the peak summer season, and during the morning and evening commuting times of the shoulder season due to the year round population in the vicinity of the intersection.

The intersection was originally reviewed as part of the 2005 Traffic Study and Strategy for the Mid-Island Area, which was completed by Greenman-Pedersen, Inc. (GPI) using data collecting in the summer of 2004. The study showed that under the 2004 traffic conditions the left turns from Old South Road onto Fairgrounds Road operated at an acceptable LOS B or better during peak times. Left and right turning movements from Fairgrounds Road onto Old South Road operated at LOS F during all peak times. Although the recommended improvement of this study was to expand the right turn lane for the Fairgrounds Road approach, the analysis showed this approach would still operate at LOS F with insufficient capacity.

In 2006, a supplemental study was completed by GPI to evaluate the intersection under a modern roundabout configuration. This study concluded that the implementation of a roundabout at this location would greatly reduce delays and would operate at an acceptable LOS C or better. This evaluation used single lane approaches to a 100 foot diameter roundabout with a 40 foot inner landscaped island with a 12 foot cobblestone apron, which could be provided without any major right of way impact on private property, but would require overhead utility pole relocation.

In 2016, a Traffic Impact and Access Study (TIAS) completed by Ron Muller & Associates as part of an Old South Road Mixed-Use Development proposal evaluated the development’s potential impact to this intersection using data collected in August 2015. This study described the intersection as continuing to operate at LOS F during all peak times with very long delays and queues on the Fairgrounds Road approach, particularly for left turn movements. Although the TIAS confirmed the roundabout would have acceptable operations with or without the development, the report recommended considering a right turn lane on the Fairgrounds Road approach to the intersection to improve capacity and operations.

Crash data in all the recent studies show that the intersection has had a crash rate that was less than the state-wide and district-wide averages for unsignalized intersection. However, this intersection is included in MassDOT’s 2012-2014 Highway Safety Improvement Program (HSIP) eligible crash clusters, which indicates it is in the top 5 percent of intersections in the Nantucket region for crash incidences and severity.

Based on the reports and studies completed to date verifying a modern roundabout configuration would add capacity and reduce unsafe conflicts, the Town has approved funding to design and permit a MassDOT approved project for construction.

Conceptual Plans

Design Studies

The purpose of these projects is to utilize Town of Nantucket’s Complete Streets Policy and the 2006 Massachusetts Highway Department’s Project Development and Design Guide and other Highway Division standards and criteria to design and construct a modern roundabout at the following three (3) intersections, as recommended in the Nantucket Master Plan and the NP&EDC’s Regional Transportation Plan (click links below for additional information on each location):

  • Surfside Road at Bartlett Road 
  • Four Corners (Sparks Ave, Surfside Rd, Atlantic Ave, and Prospect St) 
  • Old South Road at Fairgrounds Road 

Why Roundabouts?

  • “A primary benefit is the reduction of vehicle speeds in and around the roundabout. Roundabouts improve pedestrian crossing opportunities, providing mid-block refuge and the ability for pedestrians to focus on one traffic stream at a time while crossing with or without crossing guards.” – Federal Highway Administration, Safe Roads for a Safer Future
  • “In settings with large numbers of children, lowering vehicle speed has great potential for injury prevention. Pedestrian crashes involving a child most often result from the child’s error, thus slower speeds give motorists more time to react and can lessen injuries when crashes do occur.” [Retting, Ferguson, & McCartt, 2003] – National Center for Safe Routes to School, Safe Routes to Schools Guide
  • General benefits according to the National Center for Safe Routes to Schools:
    • Lower motor vehicle speeds and increased yielding behavior
    • Fewer conflict points
    • Higher visibility of pedestrians in the crosswalk
    • Lower exposure to motor vehicles because of the shortened crossing distance
    • Simpler crossing due to the splitter islands, which provide mid-crossing refuge and allow the pedestrian to focus on traffic from one direction at a time