Designing local street spacing by grey programming

Local street systems comprise networks of collectors and alleys in a block bounded by arterials. In this study we develop a model for analyzing the spacing design of local streets. The model is designed as a multiobjective grey integer programming approach, which considers three objectives: accessibility, mobility, and safety. Constraints include travel demand, the passage of emergency vehicles, the evacuation of people, the influence of noise on residents, and dimension regulation of the architectural base. Because planning work is filled with uncertainties, the model parameters and decision variables are both grey numbers, which represent possible ranges rather than crisp values. Additionally, in this study we develop the grey integer TOPSIS approach for solving the developed model and other multiobjective grey integer programming models. A mixed-use block in the new town Dan-hai is explored as a case study to verify the applicability of the model to practical work. The case study is also used to analyze the influences of traffic-calming measures on spacing design in order to identify model characteristics.