Multi-Objective Evaluation Model of Single-Lane Roundabouts

Mobility, safety, and environmental sustainability are priorities in the geometric design of roundabouts. This paper presents a multi-objective optimization model that determines elements single-lane roundabouts using all three objectives. The user can specify weights for objectives, or determine optimal weights. Mobility is defined terms roundabout delay modeled United Kingdom empirical model. Safety collision frequency based on methodology Highway Manual. Environmental represented by vehicle emissions (nitrogen oxides, hydrocarbons, carbon dioxide, monoxide) vehicle-specific power methodology. proposed directly identifies dimensions (decision variables) roundabout, including entry width, exit approach half-width, circulatory effective flare length, radius, angle, inscribed circle diameter. input data to include traffic data, site conditions, limitations guidelines. Application illustrated two actual comparison results show provides substantial improvements mobility, compared with existing conditions. In addition, requires much less effort apply traditional iterative method, as such should be interest highway designers.