| Summary |
The width and cross-sectional allocation of city streets determine how efficiently and sustainably a city can move forward. Unfortunately, the width and allocation of urban streets are usually separately determined by urban planners and traffic engineers lacking of integration and consistency. Therefore, how to optimally design the width and cross-sectional allocation of city streets simultaneously according to their neighboring land use and level in the city roadway network is particularly essential, which can provide valuable
guidelines for urban planning review process. Based on this, this study aims to develop an optimization model for cross-sectional allocation of urban streets under given road width. The model simultaneously optimizes five objectives, including human-oriented, safety, efficiency, environmentally friendly and consistency. The model optimizes the numbers and widths of lane types (for motor vehicles, motorcycles, bikes and pedestrians) as well as road ancillary facilities in association with the road level (i.e., median, public facilities strip). By setting a minimum design unit of 0.25 m, the mixed integer model can then be converted into a pure integer programming model. By using the simple weighted sum method and sets of weights for various land use types (commercial, residential, industrial…) obtained by Analytic Hierarchy Process (AHP) survey, the model are solved by total enumeration method and package software (LINGO), respectively. To show the applicability of the proposed model, a case study on Beitou-Shilin Technological Park is performed and three selected streets (Chengde Road, Fuguo Road, Chengping Road) in the park is chosen for comparisons. The results of Chengde Road show that the current allocation
lacks of pedestrian space and fails to meet the future pedestrian demand. The model suggests an allocation of four motor vehicle lanes and a 4.75m sidewalk for the extension of Fuguo Road. As for Chengping Road, it suggests an allocation of two motor vehicle lanes and a bike lane. The results suggest that the proposed model can design an optimal cross-sectional allocation towards five objectives. |
