Intelligent CCTV for Urban Design: AI-Based Analysis of Soft Infrastructure at Intersections

2026-05-06

AI Summary

This study addresses the lack of efficient, low-cost evaluation methods for soft traffic calming interventions—such as curb extensions and temporary refuge islands—by proposing a novel, non-intrusive approach that leverages existing urban CCTV infrastructure. Integrating deep learning with a perspective geometry–based speed estimation algorithm, the method enables automated analysis of vehicle behavior at intersections in real-world urban settings, facilitating rapid assessment of traffic calming effectiveness. Applied across multiple intersections in Minneapolis, the approach demonstrated that post-intervention average vehicle speeds decreased by up to 20.0%, the 85th percentile speed dropped by 17.19%, and through-traffic volumes were reduced by as much as 12.2%, thereby providing robust empirical validation of the safety benefits conferred by soft traffic calming measures.

Abstract

Artificial intelligence (AI) and computer vision are transforming transportation data collection. This study introduces an AI-enabled analytics framework leveraging existing CCTV infrastructure to evaluate the impact of soft interventions, such as temporary pedestrian refuges and curb extensions, on vehicle speed and safety. Using deep learning and perspective-based speed estimation, we evaluated driver behavior before and after interventions, with repeated post-installation monitoring in Week 1 and Week 2, in Minneapolis. Findings reveal that at unsignalized intersections, mean and 85th-percentile speeds fell by up to 18.75% and 16.56%, respectively, while pass-through traffic decreased by as much as 12.2%. Signalized intersections showed comparable reductions except one location, with mean and 85th-percentile speeds dropping by up to 20.0% and 17.19%. These results demonstrate the traffic-calming effectiveness of soft infrastructure and underscore the utility of AI-powered methods for rapid, low-cost, and evidence-based transport policy evaluation.

Problem

• soft infrastructure
• traffic calming
• intersection safety
• urban design
• transport policy evaluation

Innovation

• AI-enabled analytics
• computer vision
• perspective-based speed estimation
• soft infrastructure
• traffic calming