Transactions on Transport Sciences

Transactions on Transport Sciences X:X

Defining Maximum Intensity Levels for Pedestrians and Vehicles in Shared Space

Aneta Dostalova^a, Radim Dvorak^b,c, Josef Kocourek^a

^a. CTU in Prague Faculty of Transportation Sciences, Department of Transport Engineering and Transport Planning, Horska 3, 128 03 Praha 2, Czech Republic, matysane@fd.cvut.cz

^b. CTU in Prague Faculty of Transportation Sciences, Department of Mechanics and Materials, Na Florenci 25, 110 00 Praha 1, Czech Republic, dvorara9@fd.cvut.cz

^c. Institute of Thermomechanics of the CAS, v. v. i., Dolejškova 1402/5, 182 00 Praha 8 Czech Republic, kocoujos@fd.cvut.cz

Shared spaces are intended to accommodate pedestrians, cyclists and motorists on equal terms, yet practitioners still lack an operational tool for translating pedestrian–vehicle interactions into clear capacity limits. This study closes that gap by proposing a density-based delay model that expresses instantaneous vehicle speed as a function of local pedestrian concentration. The four free parameters of the model are calibrated with a genetic algorithm against a bank of pedestrian-vehicle scenarios generated in PTV VISSIM, allowing the analytical formulation to emulate the full microsimulation surface. Once calibrated, the model collapses rich interaction dynamics into an ‘-curve’—an envelope of pedestrian- and vehicle-flow pairs that preserves an acceptable average delay. The workflow is demonstrated on a Prague retail parking lot and shown to reproduce the observed balance between comfort, safety and throughput. By turning hours of simulation into a single design-ready curve, the framework offers planners a lightweight, reproducible means to size or retrofit low-speed shared zones and provides a foundation for further empirical and methodological extensions.

Keywords: Pedestrian Safety; Shared Space; Traffic Flow; Traffic Modeling

Received: August 25, 2025; Revised: December 13, 2025; Accepted: January 7, 2026; Prepublished online: August 28, 2026