Quiet City Project — Visualizing Urban Noise × Sensory Stress and Policy Proposals

Methodology

Research methodology and approaches adopted in this lab.

Glossary

Key terms and definitions used in this research.

Contrast Index (CI)

An event-based index at the conceptual design stage that describes noise stress as a multiplicative composite of contrast with background noise, repetition frequency, time-of-day weighting, and a source-type masking coefficient (M). This is a Phase 2 research sketch for the ISVD Quiet City Project; the M coefficients are designed to be updated post-hoc based on subjective evaluation data from Bunkyo Ward (文京区) fieldwork planned for autumn 2026 to spring 2027. This is a distinct direction from the 'dB-stress divergence index' discussed elsewhere, is not an established metric, and will be withdrawn if its independence from Zwicker Perceived Annoyance or ISO 12913 PA cannot be verified.

Related terms:Sensory Stress IndexSoundscape

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Environmental Justice

A principle and movement that seeks to correct structural imbalances in which environmental burdens are disproportionately borne by socially marginalized groups. The geographic concentration of noise harm is also a matter of environmental justice.

Related terms:Epistemic Injustice

GEMA (Geographic EMA)

Geographic Ecological Momentary Assessment. A research method that records real-time subjective experiences in conjunction with GPS location data. Particularly effective for field surveys of noise stress.

Related terms:Sensory Stress Index

Hyperacusis

A condition in which sounds of ordinary volume are perceived as unbearably loud. Frequently associated with sensorineural hearing loss and autism spectrum disorder.

Related terms:MisophoniaSensory Hypersensitivity

Low Traffic Neighbourhood (LTN)

A street engineering technique originating in London that physically excludes through-traffic using modal filters such as bollards, creating residential zones accessible only to residents and emergency vehicles. A 2024 Oxford University study found traffic within LTNs decreased by up to 51%, with corresponding reductions in noise levels.

Related terms:Modal FilterSensory Refuge Zone

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Méduse / Hydre (Acoustic Sensor / Sonic Radar)

Automated acoustic measurement technologies developed by Bruitparif (France). Méduse is a four-microphone directional sound source detection sensor (winner of the 2019 Golden Decibels Award). Hydre is an acoustic radar that evolved the Méduse technology for enforcement purposes, combining Méduse sensors with license plate recognition cameras to automatically detect noise violations from moving vehicles. The verbalization (penalty) phase was scheduled to begin in spring 2025.

Misophonia

A neurological condition in which specific sounds (e.g., chewing, keyboard typing) trigger intense aversion, anger, or anxiety. Named in 2001 by Jastreboff and Jastreboff.

Related terms:HyperacusisSensory Hypersensitivity

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Modal Filter

A street infrastructure element — such as bollards, raised surfaces, or plantings — that physically excludes through-traffic while permitting access for residents and emergency vehicles. The core component of a Low Traffic Neighbourhood (LTN).

Related terms:Low Traffic Neighbourhood (LTN)

Sensory Refuge Zone

A residential zone that protects the acoustic environment for all residents, including those with sensory hypersensitivity, through a combination of modal filters, sound-absorbing pavement, and natural acoustic barriers. A concept under development by this lab, positioned as an evolution of the LTN model. (Research stage.)

Related terms:Modal FilterLow Traffic Neighbourhood (LTN)

Sensory Stress Index

A composite index of sound environment stress based on individual sensory characteristics that cannot be captured by decibel values alone. Currently under development by this lab.

Related terms:MisophoniaHyperacusis

Sound Source Mask (M)

One of the components of the Contrast Index. A coefficient representing the contribution of sound source type (horn, motorcycle, ambulance, natural sounds, etc.) to annoyance, functioning as a 'semantic gate' in the multiplicative composition of CI. Designed using Spearman correlation values from the Hou et al. (2023) HGRL model as a literature prior, to be updated in a Bayesian manner with subjective evaluation data from Bunkyo Ward (文京区) fieldwork. Intended as a literature-based estimate rather than an intuitive value. Note: this is distinct from the psychoacoustic concept of auditory masking.

Related terms:Contrast Index (CI)

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Soundscape

A concept proposed by R. M. Schafer in 1977. A framework that treats the acoustic environment not as a physical quantity but as perceived and interpreted through the listener's subjectivity and cultural context.

Related terms:Sensory Stress Index

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Bibliography

Detailed reference list for this research.

Le radar sonore « Hydre » (Sonic Radar Hydre)

Bruitparif (2025)

An automated acoustic measurement and enforcement radar developed by Bruitparif, building on the Méduse sensor technology. Phase 1 (2022) was demonstrated at three sites: the 20th arrondissement of Paris (20区), Villeneuve-le-Roi, and Saint-Lambert des Bois. Phase 2 (verbalization, penalty phase) was scheduled for spring 2025. Also under trial in Berlin, Geneva, Brussels, and Barcelona.

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2024 Annual Report for Noise Camera Enforcement Program

New York City Department of Environmental Protection (2024)

Annual report on the NYC noise camera programme. Local Law 7 of 2024 mandated expansion to 25 cameras across five boroughs by September 2025, but appropriations were not secured and as of 2026 only nine cameras are operational (per public reporting).

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Local Law 7 of 2024 (City of New York)

New York City Council (2024)

An ordinance requiring the NYC DEP to install 25 noise cameras (5 per borough) by September 2025. Implementation is contingent on budget allocation due to the 'subject to appropriations' clause.

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The impact of a low traffic neighbourhood intervention on urban noise measured with low-cost sensors in Oxford, UK

(Oxford / University of Birmingham research team) (2024)

Published in Transportation Research Part D. Measured pre- and post-LTN intervention with eight AudioMoth low-cost sensors, confirming noise reduction and increased biotic sound at almost all observation points. Traffic within the LTN decreased by up to 51%. Results on boundary roads were mixed (some -8%, some +3%).

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Joint Prediction of Audio Event and Annoyance Rating in an Urban Soundscape by Hierarchical Graph Representation Learning

Hou, Y. et al. (2023)

Accepted at INTERSPEECH 2023. Simultaneously predicts acoustic event detection and annoyance ratings for urban soundscapes using hierarchical graph representation learning. Measures per-source-category annoyance contributions via Spearman correlation. Referenced as the literature prior for the M coefficient in the Contrast Index (CI).

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Hyperacusis and Everyday Sound Environment

Sakuma, T. (2021)

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Survey on Hyperacusis and Sound Environment Associated with Developmental Disabilities

Matsui, A., Sakuma, T. (2020)

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Geographic Ecological Momentary Assessment (GEMA) of environmental noise annoyance

Lam, K. C. et al. (2020)

A GPS-linked real-time subjective evaluation method. Referenced for fieldwork design in this lab.

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Environmental Noise Guidelines for the European Region

WHO Regional Office for Europe (2018)

Environmental noise guidelines from the WHO Regional Office for Europe. Provides noise threshold values for road, railway, aviation, and wind turbine sources.

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Sonic Autoethnographies: Personal Listening as Compositional Context

Findlay-Walsh, I. (2018)

Organised Sound 23(1):121–130. A pioneering paper applying sonic autoethnography as a methodology in the context of soundscape composition. Referenced in this lab as a precedent for first-person description of acoustic environment experience.

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Noise sensitivity, rather than noise level, predicts the non-auditory effects of noise in community samples

Park, J. et al. (2017)

Published in BMC Public Health. A population-based survey of 1,836 Korean adults. Among those with high noise sensitivity: depression OR=2.18, insomnia OR=2.08. Ldn was not a significant predictor, demonstrating that sensitivity is the primary predictor of health effects. Supports the central research question: 'dB is not the whole story.'

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Auditory and non-auditory effects of noise on health

Basner, M. et al. (2014)

Published in The Lancet. A comprehensive review of both auditory and non-auditory health effects of noise.

DOI Link

ASPECTSS Design Index — 7 Architectural Design Principles for Autism Spectrum Disorder

Mostafa, M. (2014)

DOI Link

Autoethnography: An Overview

Ellis, C., Adams, T. E., & Bochner, A. P. (2011)

Forum: Qualitative Social Research, 12(1), Article 10. A foundational paper defining the methodology and legitimacy of autoethnography. Argues that first-person description by researchers with lived experience contributes to hypothesis generation.

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Annoyance from transportation noise: relationships with exposure metrics DNL and DENL and their confidence intervals

Miedema, H. M. E. & Oudshoorn, C. G. M. (2001)

Environmental Health Perspectives 109(4):409–416. A meta-analysis of 45 studies involving 190,000 participants. Demonstrates that at the same Lden, the percentage highly annoyed (%HA) differs by source type — aircraft > road > rail — establishing that dose-response curves are source-type-specific. Provides the rationale for designing the M coefficient in CI as a source-type weight.

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The Soundscape: Our Sonic Environment and the Tuning of the World

Schafer, R. M. (1977)

The foundational text of the soundscape concept. Proposes a framework for understanding the acoustic environment through the lens of culture and perception.