Imperial College London

Dr Ke Han

Faculty of EngineeringDepartment of Civil and Environmental Engineering

Senior Lecturer



+44 (0)20 7594 5682k.han Website CV




Mrs Maya Mistry +44 (0)20 7594 6100




605Skempton BuildingSouth Kensington Campus






BibTex format

author = {Yu, C and Ma, W and Han, K and Yang, X},
doi = {10.1016/j.trb.2016.12.015},
journal = {Transportation Research Part B - Methodological},
pages = {135--153},
title = {Optimization of vehicle and pedestrian signals for isolated intersections},
url = {},
volume = {98},
year = {2017}

RIS format (EndNote, RefMan)

AB - In most traffic signal optimization problems, pedestrian traffic at an intersection receives minor consideration compared to vehicular traffic, and usually in the form of simplistic and exogenous constraints (e.g., minimum green time). This could render the resulting signal timings sub-optimal especially in dense urban areas with significant pedestrian traffic, or when two-stage pedestrian crosswalks are present. This paper proposes a convex (quadratic) programming approach to optimize traffic signal timings for an isolated intersection with one- and two-stage crosswalks, assuming undersaturated vehicular traffic condition. Both vehicle and pedestrian traffic are integrated into a unified framework, where the total weighted delay of pedestrians and vehicles at different types of crosswalks (i.e. one- or two-stage) is adopted as the objective function, and temporal and spatial constraints (e.g. signal phasing plan and spatial capacity of the refuge island) are explicitly formulated. A case study demonstrates the impacts of incorporating pedestrian delay as well as geometric and spatial constraints (e.g., available space on the refuge island) in the signal optimization. A further analysis shows that a two-stage crosswalk may outperform a one-stage crosswalk in terms of both vehicle and pedestrian delays in some circumstances.
AU - Yu,C
AU - Ma,W
AU - Han,K
AU - Yang,X
DO - 10.1016/j.trb.2016.12.015
EP - 153
PY - 2017///
SN - 0191-2615
SP - 135
TI - Optimization of vehicle and pedestrian signals for isolated intersections
T2 - Transportation Research Part B - Methodological
UR -
UR -
UR -
VL - 98
ER -