Design/Peer Review Overview
The MTJ design/peer review approach utilizes the operational characteristics of roundabouts to maximize community and roadway benefits and minimize adverse impacts and potential costs. This practical analysis and design approach allows for optimizing for safety and operations for all modes while minimizing undesirable and/or detrimental community impacts to adjacent land-uses.
Because roundabouts are not homogeneous each must be designed to address the traffic flows, site constraints, context, and project objectives of the particular intersection or corridor.
The MTJ design/peer review approach ensures:
- Adherence to proven design principles
- State-of-the-practice design techniques
- Optimal roundabout safety and operational performance
MTJ’s understanding of both roadway and roundabout design principles includes:
- Identification of cost savings through ROW minimization or avoidance
- Checking growth projections with sensitivity testing
- Facilitating risk management/avoidance by ensuring proper design
Operational Analysis – Traffic Modeling
MTJ is well versed in the use of applicable operational tools for roundabout analysis and how this influences design. The operational analysis is a foundational element of roundabout design. Understanding the expected operations for a given layout is essential in the roundabout design process. MTJ conducts operational performance analysis and checks (to include sensitivity testing) with the roundabout-specific capacity analysis software program Rodel v1.88, as well as HCM, Vissim, and Sidra, as necessary.
The MTJ design/peer review optimization process includes these components:
- Match capacity to demand: Avoid over-design (see Operational Analysis above)
- Safety: Ensure safety for all modes – pedestrians, bicycles, vehicles
- Context: Apply traffic and roadway design principles
- Apply FHWA Performance Checks (NCHRP Report 672, Roundabouts: An Informational Guide)
- Pavement markings and signing
- Accessibility for pedestrian crossings at multi-lane roundabouts (NCHRP Report 674)
- Oversized-Overweight (OSOW) Review Analysis