Lyon Metropolitan Area Research Articles

Addressing the sustainable urbanism paradox: tipping points for the operational reconciliation of dense and green morphologies

To improve biodiversity and human living conditions in the Anthropocene, urban forms must reconcile density with vegetation to meet the dual sustainability-liveability challenge. This paradox poses a dilemma for urban planners and is a critical research issue requiring comprehensive analyses. Multi-family residential housing holds the potential to achieve balanced density-greening, proximity ecosystem services and human-nature connectedness, but meeting such objectives relies on finding balanced morphologies and metrics at an operational scale. Analysing 11,593 plots in the Lyon metropolitan area (France) using a systemic approach, we identified critical tipping points in morphology and greening. Density explained only 6% of Plot Greening, while morphology and landscaping accounted for 94%. We identified an open-space ratio (unbuilt area/floor area) >0.3 as a morphological threshold to achieve sustainable green supply. Operational morphologies balancing density and greening were modelled and illustrated across building heights, providing guidelines for emerging regulatory tools in sustainable urban planning.

Urban Dark Fiber Distributed Acoustic Sensing for Bridge Monitoring

Distributed Acoustic Sensing (DAS) technology applied to telecommunication fiber optic networks offers new possibilities for Structural Health Monitoring (SHM). The dynamic responses of five bridges are extracted along a 24 km long optical fiber crossing the Lyon metropolitan area in France. From their characteristic seismic signatures, three physical parameters informing on the health of structures have been determined: vibration frequencies, damping and modal shapes. The fiber measurements are in agreement with velocimetric data serving as reference. The telecom optical fiber records the dynamic response of bridges in several directions and thus allows the reconstruction of 3D deformation modes using their orthogonality properties. Time tracking of frequencies, commonly used to assess structural integrity, shows that the average values of natural frequencies vary cyclically between day and night. The increase in frequencies during the night does not exceed 2% and probably reflects an overall stiffening of the structures due to the drop in temperature. The telecom fiber allows to obtain deformation and damping identity of structures, highlighting soil-structure coupling between the bridge and underlying soil. This study shows that it is possible to assess the spatial and temporal variability of bridge dynamic response from DAS data using existing fiber networks.

Contribution of different land use catchments on the microplastic pollution in detention basin sediments

The assessment of microplastic (MP) pollution in urban areas is essential considering its abundance in freshwater, particularly due to urban wet weather discharge. The precise sources of MPs must be identified to better understand its characteristics. This study examines the relationship between MP pollution in detention basin sediments and land use in the investigated catchments. The study of stormwater management infrastructure, mainly in detention basins, has enabled the quantification of MP abundance in sediments conveyed by stormwater in urban areas. Sediment sampling was conducted in ten detention basins and one combined sewer overflow (CSO) structure in the Lyon metropolitan area, France. These basins correspond to stormwater outlets of representative urban catchment areas. MP extraction involves densimetric separation and organic matter degradation. MPs were then characterized using micro-Fourier infrared spectroscopy and siMPle software. This protocol identified MPs between 50 and 500 μm in the study sites. This study highlights the high abundance in the collected sediment samples, ranging from 2,525 to 1,218,82 MP kg−1 by dry weight sediment. The MPs found have a median size around 115 μm, making them very small MPs that are mainly composed of polypropylene followed by polyethylene and polystyrene or polyethylene terephthalate. The abundance of MPs in sediments is associated with the land use type. Catchments in predominantly industrial and commercial zones were more significantly polluted with MPs compared with those in predominantly agricultural or heterogeneous zones. Finally, statistical analyses revealed links between sedimentary and urban parameters and MPs concentrations. Several recommendations are given for future research, notably concerning the analyzing of stormwater sediments to understand the sources of MP pollution.

The increasing age of respiratory syncytial virus-related hospitalisation during COVID-19 pandemic in Lyon was associated with reduced hospitalisation costs

BackgroundPreventive measures applied during the COVID-19 pandemic have modified the age distribution, the clinical severity and the incidence of Respiratory Syncytial Virus (RSV) hospitalisations during the 2020/21 RSV season. The aim of the present study was to estimate the impact of these aspects on RSV-associated hospitalisations (RSVH) costs stratified by age group between pre-COVID-19 seasons and 2020/21 RSV season. MethodsWe compared the incidence, the median costs, and total RSVH costs from the national health insurance perspective in children < 24 months of age during the COVID-19 period (2020/21 RSV season) with a pre-COVID-19 period (2014/17 RSV seasons). Children were born and hospitalised in the Lyon metropolitan area. RSVH costs were extracted from the French medical information system (Programme de Médicalisation des Systémes d’Information). ResultsThe RSVH-incidence rate per 1000 infants aged < 3 months decreased significantly from 4.6 (95 % CI [4.1; 5.2]) to 3.1 (95 % CI [2.4; 4.0]), and increased in older infants and children up to 24 months of age during the 2020/21 RSV season. Overall, RSVH costs for RSVH cases aged below 2 years old decreased by €201,770 (31 %) during 2020/21 RSV season compared to the mean pre-COVID-19 costs. ConclusionsThe sharp reduction in costs of RSVH in infants aged < 3 months outweighed the modest increase in costs observed in the 3–24 months age group. Therefore, conferring a temporal protection through passive immunisation to infants aged < 3 months should have a major impact on RSVH costs even if it results in an increase of RSVH in older children infected later in life. Nevertheless, stakeholders should be aware of this potential increase of RSVH in older age groups presenting with a wider range of disease to avoid any bias in estimating the cost-effectiveness of passive immunisation strategies.

Role of mammography accessibility, deprivation and spatial effect in breast cancer screening participation in France: an observational ecological study

BackgroundThe detection of cancer in its early latent stages can improve patients’ chances of recovery and thereby reduce the overall burden of the disease. Our objectives were to investigate factors (geographic accessibility and deprivation level) affecting mammography screening participation variation and to determine how much geographic variation in participation rates can be explained by spillover effects between adjacent areas, while controlling for covariates.MethodsMammography screening participation rates between 2015 and 2016 were calculated by census blocks (CB), for women aged 50–74 years, residing in Lyon metropolitan area. Global spatial autocorrelation tests were applied to identify the geographic variation of participation. Spatial regression models were used to incorporate spatial structure to estimate associations between mammography participation rate and the combined effect (geographic accessibility and deprivation level) adjusting for modes of travel and social cohesion.ResultsThe mammography participation rate was found to have a statistically significant and positive spatial correlation. The participation rate of one CB was significantly and positively associated with the participation rates of neighbouring CB. The participation was 53.2% in residential and rural areas and 46.6% in urban areas, p < 0.001. Using Spatial Lag models, whereas the population living in most deprived CBs have statistically significantly lower mammography participation rates than lower deprived ones, significant interaction demonstrates that the relation differs according to the degree of urbanization.ConclusionsThis study makes an important methodological contribution in measuring geographical access and understanding better the combined effect of deprivation and the degree of urbanization on mammography participation and other contextual factors that affect the decision of using mammography screening services -which is a critical component of healthcare planning and equity.

Institutional changes in farmland governance emerging from a collective land preservation procedure upholding local food projects: Evidence from a French case study

The issue of agricultural land loss in urban and suburban areas, paired with the societal demand for local food provision, calls for the development of innovative procedures aiming at preserving agricultural land to secure local food provision. However, the implementation of such procedures raises concerns about the evolution of land governance for food purposes. From this perspective, this article analyses changes brought about by the French procedure for the protection of natural and agricultural peri-urban areas (PAEN: périmètres de protection des espaces agricoles et naturels), in light of the framework of the institutional design principles mainly developed by Elinor Ostrom. By analysing the PAEN procedure in the Lyon Metropolitan area in France, we show how this procedure is leading to evolutions in farmland governance, is participating to the attribution of new property rights to the actors involved in this governance and is questioning the status of agricultural land.

What drives the changes in public transport use in the context of the COVID‐19 pandemic? Highlights from Lyon metropolitan area

This article focuses on the decline in the use of public transport in the context of the coronavirus disease 2019 (COVID‐19) crisis in the Lyon metropolitan area, France. Using data from a web‐based survey, supplemented by traffic counts and a qualitative survey, we explain this decline by the decrease in out‐of‐home activities such as work and the concomitant increase in teleworking, as well as by modal transfers. We test these explanations by multiple regression models that include socio‐demographic, residential, professional and attitudinal variables. We conclude with a discussion on the lasting of these changes and their implications for mobility policy.

Application of the absolute environmental sustainability assessment framework to multifunctional systems – The case of municipal solid waste management

The Absolute Environmental Sustainability Assessment (AESA) framework is an emerging field in environmental research that aims at comparing the estimated environmental burden generated by a system on its life cycle to the carrying capacity that can be assigned to this system, i.e. the amount of impacts that it can cause without causing unacceptable impairment of ecosystem functional integrity. This paper aims to expand the AESA framework to multifunctional systems. We applied it to a simplified case study based on municipal solid waste (MSW) management, since such a system provides several functions such as reduction of the quantity and toxicity of waste, production of heat, electricity or secondary materials. Thus, we could identify the specific questions that arise from this multifunctionality in the context of AESA.Based on the theory of AESA, we developed a four-steps methodology to identify the most significant impacts at both system and global scales. That methodology consisted of (step 1) quantifying the impacts of the studied system with conventional Life Cycle Assessment (LCA) followed by a normalisation step; (step 2) quantifying the number of beneficiaries from this system; (step 3) identifying impact categories for which the studied system causes significant impacts and global carrying capacities are exceeded; and (step 4) quantifying the Assigned Carrying Capacity (ACC) of the system, based on a utilitarian perspective and its contribution to the satisfaction of human needs.We then applied this methodology to a simplified model of the MSW management implemented in the Lyon Metropolitan Area (France), as a proof of concept. Steps 1 to 3 helped elaborate a hierarchy of impact categories, highlighting which ones should be reduced in priority. Step 4 required significant knowledge about how the functions of the studied system were used, both directly and indirectly, to satisfy human needs. We used national Supply and Use Tables and several simplifying hypotheses to that end. We also tested different sharing principles based on macroeconomic indicators. This variety of sharing principles helped refine the hierarchy developed in Step 3 by identifying which carrying capacities were most certainly exceeded by the studied system.

Retrospective Modeling of NO2 and PM10 Concentrations over the Lyon Metropolitan Area (France), 1990–2010—Performance Evaluation, Exposure Assessment and Correlation between Pollutants

Numerous cancers develop years after subjects have been exposed to chemical compounds. Thus, environmental epidemiological studies need to accurately reconstruct exposures over long periods. To estimate exposure to NO2 and PM10 concentrations, we modelled ground-level air concentrations, at very fine temporal (1 h) and spatial (10 m) resolutions, over a large European metropolitan area and at subject’s address of a French national cohort, for five different years (1990, 1995, 2000, 2005 and 2010). Model performances were assessed by comparing the annual modelled concentration against monitoring station measurements. As input data, we used background concentrations from a large-scale dispersion model. The relevance of our approach was assessed by comparing results in 2010, with a modelling using monitoring values as background data. The comparison with measurement data showed good performance of the model for the majority of the period, with a performance declined in 1990. Concentrations at the subject’s residence decreased by 45% for PM10 and 38% for NO2. The proportion of subjects exposed above the WHO recommendations declined from 100% to 50% for PM10 and from 79% to 16% for NO2. The results of this study would provide a reference for future models to assess chronic exposures to PM10 and NO2 on a larger scale.

Urban rural paradox -when easy access to mammography services does not mean active participation

Abstract Introduction The detection of breast cancer in its latent stages through mammography screening can improve patient's chances of recovery. However, geographic variation in mammography participation remains. Our objectives were first to assess whether the geographic accessibility of mammography-screening services influences mammography-screening participation and second to estimate the extent to which geographic variation in the use of cancer screening can be explained by spillover effects between adjacent areas, while controlling for covariates. Methods Mammography-screening services participation rates were calculated, for women aged 50-74 years who live in Lyon metropolitan area and did a mammography between 2015-2016 after being invited with a letter by the mammography screening program. We used spatial autoregressive models to estimate the extent of spatial spillover effects by applying spatial lag models. The geographic accessibility (availability, distance and affordability) on participation was evaluated adjusting on socioeconomic characteristics of census blocks. Results We found evidence of urban rural paradox. The mammography screening participation was 53.2% in residential and rural areas and 46.6% in urban and active areas, p &amp;lt; 0.001. Conversely to rural areas, women living in urban census blocks had high availability, lower distance to the closest mammography services, and lower mammography screening participation. Moreover, the coefficients for the spatial lag are significant and positive. The positive spatial lags indicate that screening utilization rates are determined by knowledge spillovers and geographic proximity between adjacent areas. Conclusions This study makes an important methodological contribution to measure access to services and better understand the variety of community contextual factors that drive mammography use decisions; which is a critical component of health care planning and equity almost everywhere. Key messages Evidence of urban rural paradox in mammography screening participation. Screening utilization rates are determined by knowledge spillovers and geographic proximity between adjacent areas.

Urban renewal in post-industrial districts: the example of Lyon Metropolis

Urban renewal issues in France are very often discussed with reference to the demolition or renovation of large-scale housing estates. But these issues also concern former industrial areas which have their own distinct architectural, social, and economic difficulties. This article aims to present analysis of these differences using the example of two case studies in the Lyon metropolitan area, the second largest agglomeration in France. First, we outline the background of urban policy in France and Lyon in particular, together with mapping “priority geography” of urban policy in Lyon. Our two case studies, La Saulaie and Carré de Soie, are located in suburbs of the metropolis. Through our analysis of the social and spatial features of these two renewal projects which are currently under way, we demonstrate that urban renewal policies in France are multi-layered, and that the case of Lyon illustrates especially robust engagement on the part of local authorities. Tackling poverty and isolation are the priorities in La Saulaie. In Carré de Soie, the challenges are to create a public transportation hub, a new housing market, and to attract companies to this new secondary centre. We also show that urban renewal operations are not limited to the areas defined by the “priority geography”.

Mapping Variation in Breast Cancer Screening: Where to Intervene?

Small geographic areas with lower mammography screening participation rates may reflect gaps in screening efforts. Our objective was to use spatial analyses to understand disparities in mammography screening use and to identify factors to increase its uptake in areas that need it in Lyon metropolitan area, France. Data for screened women between the ages of 50 and 74 were analyzed. Census blocks of screened and non screened women were extracted from the mammography screening programme 2015–2016 dataset. We used spatial regression models, within a generalized additive framework to determine clusters of census blocks with significantly higher prevalence of non-participation of mammography screening. Smoothed risk maps were crude and adjusted on the following covariates: deprivation index and opportunistic screening. Among 178,002 women aged 50 to 74, 49.9% received mammography screening. As hypothesized, women living in highly deprived census blocks had lower participation rates compared to less deprived blocks, 45.2% vs. 51.4% p < 0.001. Spatial analyses identified four clusters, one located in an urban area and three in suburban areas. Moreover, depending on the location of the cluster, the influence came from different variables. Knowing the impact of site-specific risk factors seems to be important for implementing an appropriate prevention intervention.

Categorization and ethnicization of Algerians within Lyon’s housing and urban policies (1950–1970)

According to the ‘French Republican integration pattern’ – based on the principle of colour-blind universality – naming people using ethnic or racial references is illegal in the administration’s documentation as well as in the census. Yet, aspects of the colonial rights system were adopted into the French Republican ideology, thereby constituting a very specific relationship between nationality and citizenship in the administrative management of colonial natives on French mainland soil. This paper reveals the ambiguities of the Republican ideas when they were implemented by street-level administrators within Lyon’s metropolitan area (1950–1970). Examining the administration’s documentation in the Archives of the Rhône Department (ARD), this paper demonstrates how the Ministry of the Interior took leadership in the welfare sector, especially in housing and urban policies. Its role and work built upon the roots of institutionalized racism which accompanied the settlement of Algerian populations in France, even after Algeria’s independence (1962). By institutionalizing racial treatment, the successive administrations in charge of housing and urban policies within the Lyon metropolitan area have contributed to the legitimization of an ideology of segregation based on opposing aims: on the one hand, the mixing and coexistence of different cultural and ethnic groups, and on the other hand, the adherence to a supposed ‘tolerability threshold’ using arbitrarily developed quotas for the settlement of Algerians.

Urban toll and electric vehicles: The winning ticket for Lyon Metropolitan Area (France)

The financial situation of the Lyon's public transport network (France) is satisfactory, however its financial structure evolution and the amount of funding requirement revealed the first signs of concern. To get revenues, one of the considered solutions is to implement an urban road toll. Adding to well-known congestion reduction, this solution would get car drivers to contribute better, and it would also lead to reducing pollution and greenhouse gas emissions. In these circumstances, it is necessary to assess the potential effects of implementing this type of pricing solution. In this paper, we propose to evaluate this new pricing measure with respect to several urban indicators (environmental, accessibility, social inequality, public transport performance, public funding requirements). We used the MOSART modelling platform to test several pricing solutions for the Lyon Metropolitan Area based on several possible scenarios for the future (2030). The analysis of our results shows that it is possible to implement an urban toll capable of generating new revenues without increasing inequality. Furthermore, if it associated to the transformation of the fleet of vehicles into electric vehicles, it would also generate positive results regarding CO2 emissions. As a consequence, urban road toll and electric vehicles become the winning ticket for Lyon Metropolitan Area in the future.

Assessment of long-term exposure to airborne dioxin and cadmium concentrations in the Lyon metropolitan area (France)

Identifying the long-term effects of airborne pollutants requires the computation of the spatial and temporal variability of their concentration in air to estimate the exposure of the population. To estimate exposure levels of individuals in a breast cancer case control study nested in a national prospective cohort, we determine here the differential impact of a variety of cadmium and dioxin sources on urban air over a large urban area and over a period of almost 20years.To that end, we couple an emission model, to estimate dioxin and cadmium atmospheric annual releases, with an urban dispersion model in order to compute pollutant concentration fields at a fine temporal (1h) and spatial (25m) resolution. The reliability of the modelling chain is compared to two types of measurement: i) localized industrial emissions and ii) dioxin and cadmium air monitoring data (from 2007 to 2008), collected at a fixed station, placed in the city centre, as well as at three mobile short-term dioxin monitoring stations, located in the suburbs (the latter providing dioxin data, only). Comparisons between measured and estimated emissions show non-negligible difference, with a correlations for dioxin (rs=0.42) and cadmium (rs=0.41). Despite this, mean values between estimated emissions and emission measurements are close to each other, in particular for cadmium. Weekly average modelled concentrations show an overall good agreement with weekly average measured concentrations in spring and summer but are generally lower than monitored data in winter due to peak concentrations from diffuse sources representing an important proportion of emissions in 2007/2008. The model provides better results for cadmium than for dioxin. Despite the relevant errors in the model predictions, the model meets the validation criteria, defined by Chang and Hanna for an urban dispersion model.Simulation scenarios of air pollutant concentrations, reconstructed over the last 20years, show the effects of the variability of the pollutant sources over time with decreasing levels of dioxin and cadmium concentrations in air. This is primarily due to the reduction in localized industrial releases, which results in a general trend of homogenization of the exposure of the population.The model further allows us to dissociate the contribution of different types of pollutant sources on the population exposure. The impact on local concentrations due to industrial emissions, which were originally responsible for the major impact on air quality, is shown to drop over the years by 99% and 92% for dioxin and cadmium, respectively. Today, the major contributions are due to diffuse miscellaneous sources in the case of dioxin and to traffic-related emissions for cadmium.Average modelled concentrations at the study subjects' residential locations range from 10.2 to 82.1fg-TEQ/m3 for dioxin and 0.10 to 1.6ng/m3 for cadmium and are comparable with data from the literature.The study results will be essential to increase the accuracy of the assessment of long-term airborne dioxin and cadmium exposure and improve the results of epidemiological studies.

The impacts of urban pricing on social and spatial inequalities: The case study of Lyon (France)

With the aim of making a city sustainable, this paper evaluates the impact of setting up urban toll on inequalities. We use several indicators (Gini, Theil and Atkinson indices) to measure changes in the concentration of incomes and gravity-based accessibility. In the case of the Lyon Metropolitan Area (France), we simulate a cordon pricing and evaluate its impacts on inequalities. We adopt a comparison-based approach to reduce the bias resulting from the spatial division. In agreement with the literature, we show that different inequality indicators produce contrasted and sometimes contradictory results, both at the scale of zones or metropolitan level. Results from Theil and Atkinson indicators point out introducing a toll can reduce inequalities in the most peripheral zones. Although we observe an accessibility improvement, particularly for central zones, the first ring (adjacent to the toll zone) is the most adversely affected by toll.

Simuler les évolutions de l’utilisation du sol pour anticiper le futur d’un territoire

L’article propose l’analyse critique d’une demarche de geoprospective qui s’est deroulee dans le bassin versant de l’Yzeron, en peripherie lyonnaise. Cette experience a consiste a integrer dans une demarche de prospective territoriale, menee dans le cadre d’un atelier participatif, la discussion de scenarios d’evolution de l’utilisation du sol a l’horizon 2030. Ces scenarios ont ete construits a partir de methodes et d’outils numeriques de modelisation et de simulation. Apres une mise au point conceptuelle sur les questions de prospective, prospective territoriale et geoprospective, l’article detaille la demarche mise en œuvre : mode d’organisation de l’atelier, elaboration des modeles, discussion des resultats. Enfin, la compatibilite des methodes de modelisation et de simulation spatiales avec les principes de la prospective territoriale est discutee a partir des observations des participants et des constatations des auteurs.

Road pricing: How people perceive a hypothetical introduction. The case of Lyon

Following Singapore (1975), some metropolitan areas introduced pricing schemes to make car users aware of the real costs of their trip. This research looks at citizens׳ reactions to the hypothetical introduction of a road pricing scheme in Lyon (France). People׳s perceptions were investigated through a sample of 61 persons selected according to a stratified sampling plan. A web-questionnaire was administered to the participants, and eight focus groups were then organised, each including about 7–8 persons. The focus groups allowed us to investigate the participants׳ opinions, emotions, and reactions to the hypothetical introduction of different road pricing schemes in the urban area.This research has largely confirmed what found in previous studies and its key additional contribution is the clustering of citizens according to their reactions. Different groups of people showed dissimilar attitudes and opinions about the effect of road pricing, but the whole sample agreed upon the need for a coherent policy both for transport planning and management in the Lyon metropolitan area, while respecting freedom of mobility. In fact, citizens expect that a reduction of their freedom to move by car should be compensated with a strong and clear policy to improve the alternative modes and want to know clearly how revenues will be spent. A clear communication policy should be defined and this should be tailored according to the different groups defined in this paper.

Climate-Energy Policies, Heat Provision, and Urban Planning: A Renewal of Interest in District Heating in France: Insights from National and Local Levels

How do climate and energy objectives influence the renewal of the role of network infrastructures in urban planning and the running of urban systems? The example of the revival of interest in district heating networks provides a few possible answers to this question, which is central to the understanding and characterization of the conditions for carrying out the urban energy transition. In this paper, we study this example by analyzing recent changes in French regulations and the process of creating an intercommunal energy-related competence in the Lyon metropolitan area. Emphasis is placed on the institutional and political conditions surrounding a change in governance as well as the underlying justifications in the reconsideration of an existing infrastructure in view of new energy, climate, and social challenges within a specific urban context. Our study has been carried out in reference to several discussions on urban planning and on institutional, political, and spatial factors that shape urban infrastructure regimes.

Efficient Allocation of Electric Vehicles Charging Stations: Optimization Model and Application to a Dense Urban Network

The deployment of Electric Vehicles (EVs) needs an optimized and cost-effective implementation of charging stations. As a decision support tool for network design, we define a methodology to allocate charging stations in a real network. This study uses trip OD matrix information from household travel survey coupled with a dynamic vehicle model to evaluate EVs consumption based on realistic trips (urban drive cycles). These trips are computed based on routing tools and supplied with elevation information. This enables an accurate characterization of energy needs in the Lyon Metropolitan Area. All these parameters are used as inputs of an integer linear optimization program for the location of charging stations. The methodology is based on an adaption of the classic fixed charge location model with a p-dispersion constraint. The results indicate that this methodology can help the future implementation of charging stations at an urban scale.