Network Emissions / Vehicle Flow Management Adjustment toolkit (NEVFMA)

Case Study Overview

Winner of the 2021 ITS UK Award for Innovative Use of Technology and the TechWorks Green Technology Award 2021, sponsored by yieldHUB. Aimsun developed the Network Emissions / Vehicle Flow Management Adjustment (NEVFMA) toolkit by reusing existing Oxfordshire County Council and National Highways traffic monitoring infrastructure, including 197 real-time traffic flow monitoring locations.

Winner of the 2021 ITS UK Award for Innovative Use of Technology and the TechWorks Green Technology Award 2021, sponsored by yieldHUB

National Highways wanted to enhance public spaces with strategies aimed at improving network capacity to deliver better air quality and accessibility to all, across regional and strategic networks, in the Oxfordshire region.

Solution

Aimsun developed, calibrated, and validated a model including typical day patterns for 24 hours and 10 different day types. The model refresh included updating signal timings, public transport, and adding detail to the imported Oxford Strategic Model, such as curvature, lane detail, and individual vehicle behavior.

The dynamic model covers an area bounded by the M40 to the east, the A34 to the north and west, the southern bypass to the south with macroscopic extents representing the whole of the county.

As the model has analytical and simulated predictions, both recurring and unusual event responses can be tested in under 10 minutes giving operators confidence their decision will work toward improving air quality in the same peak period.

Aimsun developed the Network Emissions / Vehicle Flow Management Adjustment (NEVFMA) toolkit by reusing existing Oxfordshire County Council and National Highways traffic monitoring infrastructure, including 197 real-time traffic flow monitoring locations.

The system is expandable, so more sensors can be added as the monitoring is extended and new locations come online. A further 18 Zephyr® air pollution sensors (developed by EarthSense in collaboration with Siemens Mobility) were deployed to develop an air dispersion model that integrates with Aimsun Live.

Aimsun Live uses the London Emissions Model to predict pollutants on the network over the next hour, for four alternative model scenarios, before EarthSense undertakes dispersion modeling by applying background and meteorological effects to the prediction. Regions are monitored in the model with key performance indicators indicating which strategy from the alternative scenarios can increase or lower the local pollutants.

The system delivered an average 7% decrease in emissions, with improvements of up to 40% recorded on some days.