Citywide traffic sensor network in Nova Gorica, Slovenia: 2025-2026 telraam S2 dataset

This article describes a multimodal traffic dataset collected through a network of 26 Telraam S2 sensors deployed across Nova Gorica, Slovenia, within the framework of the Interreg Central Europe EnCLOD project. The network comprises 23 indoor window-mounted units and 3 experimental outdoor units, installed along arterial corridors, residential connectors, and sections of the city's ring road. Each Telraam S2 device is a low-cost, citizen-science-oriented Internet of Things (IoT) traffic counter equipped with a Kendryte K210 edge AI chip that performs real-time object detection and classification directly on-device, transmitting only anonymized, aggregated counts via a built-in cellular connection (LTE-M/NB-IoT). The dataset contains 15-minute interval time-series records for each sensor location. Each record includes directional counts for pedestrians, bicycles, motorcycles, cars, light trucks, trucks, buses, trailers, tractors, and strollers, as well as a consolidated night-time detection category. Derived metrics include car speed distribution histograms in 10 km/h bins and the V85 (85th percentile) speed per interval. Accompanying metadata provide sensor coordinates, street names, segment identifiers, installation type, and uptime quality indicators. No images or video are stored or transmitted by the devices; all processing occurs on board, ensuring compliance with privacy regulations. The data were exported from the Telraam dashboard and are archived as structured Excel (.xlsx) files, with CSV mirrors, on Zenodo under a CC BY-NC 4.0 license. This is the first fine-grained, multi-modal urban traffic dataset for Nova Gorica, a city that previously lacked systematic traffic monitoring infrastructure. The dataset is suitable for reuse in transport modelling, modal share analysis, speed behaviour assessment, air-quality exposure linkage, and urban mobility planning, and may serve as a reference for replicating low-cost distributed sensor deployments in comparable European cities.