U.S. 202 / NH 124 / Main St. / Stratton Rd.
MTJ Roundabout Engineering reviewed the proposed roundabout application at the intersection of US 202/NH 124/Main Street/Stratton Road in Jaffrey, NH. We developed two revised concept designs to meet the project goals and objectives for this roundabout application.
Key design goals and objectives were to develop horizontal geometric designs to:
- Optimize safety for all modes
- Accommodate large truck movements
- Identify and minimize impacts to surrounding adjacent properties.
Based on our review we developed a revised single-lane 5-leg design and single-lane 4-leg design configuration. Our initial sketch-level redesign strived to maintain similar impacts to those shown in the original design. However, we found these minimal revisions would not accommodate necessary large truck movements. Therefore, building upon the MTJ sketch-level redesigns, we developed higher level concept designs that provide safety for all modes and accommodate necessary large truck movements while striving to minimize impacts. These higher level concept designs identify planning level land impacts to accomplish these project objectives.
We analyzed the provided 2040 long-range Design Year AM/PM traffic with the roundabout-specific analysis program Rodel v 1.96. Rodel provides an accurate understanding of the expected performance of roundabouts.
- 4-leg alternative and 5-leg alternative
- Minimized impacts to adjacent land uses
- Maximized community benefits
- Large truck movement accommodations
- Optimized safety for all modes
- Business access accommodations
- Operational analysis with Rodel