Effects of 30km/h speed zones and limits interventions (including 30 km/h cities) in urban environments on road traffic crashes: Application to the Great Lyon metropole

13 Mar 2024
Job Information

Organisation/Company

Université Gustave Eiffel – Site de Lyon-Bron

Research Field

Computer science » Database management
Environmental science » Ecology
Medical sciences

Researcher Profile

Recognised Researcher (R2)
Leading Researcher (R4)
First Stage Researcher (R1)
Established Researcher (R3)

Country

France

Application Deadline

14 Apr 2024 – 22:00 (UTC)

Type of Contract

Temporary

Job Status

Full-time

Offer Starting Date

1 Oct 2024

Is the job funded through the EU Research Framework Programme?

Not funded by an EU programme

Is the Job related to staff position within a Research Infrastructure?

No

Offer Description

Effects of 30km/h speed zones and limits interventions (including 30 km/h cities) in urban environments on road traffic crashes: Application to the Great Lyon metropole

 

Keywords: 30 km/h zones, speed limit reduction, before-and-after studies, road traffic crashes, collisions, vulnerable road users, interventions, difference-in-differences models

 

Overview of the PhD project

 

BACKGROUND:

Road safety is a major public health problem. In 2023, although the global death toll has fallen by 5% since 2010, road crashes are still responsible for 1.19 million deaths and 20 to 50 million injuries worldwide every year, according to the latest World Health Organization (WHO) report on road safety (1,2). They are also, according to the latest WHO data, the leading cause of death among children and young people aged 5 to 29, and one of the leading sources of avoidable mortality (1).

Speed is one of the main components on which we can act to reduce the risk and severity of road traffic crashes. A reduction in speed allows better visibility (a better field of vision), better reaction time, and therefore a reduction in braking distance, which in turn reduces the risk of accidents (3,4). Also, in line with physical principles, the greater the speed, the greater the amount of kinetic energy released on impact, whereas the human body can only tolerate forces up to a certain threshold. Mass also comes into play in determining which antagonist in a collision will absorb how much of the energy released. As this absorption is inversely proportional to mass, the lighter vehicle will be more severely affected than the heavier one. This phenomenon is even more pronounced for vulnerable road users such as pedestrians, cyclists and motorized two-wheelers, who have no car body around them to absorb part of the energy released during a collision. This makes it an essential parameter for protecting these users.

Policies to reduce traffic speeds to 30 km/h (or 20 miles per hour, around 32 km/h) have been in place in Anglo-Saxon countries and Europe for over thirty years. The appeal of measures to reduce speeds to 30 km/h in built-up areas is based on risk curves developed in studies such as that by Rosén et al. (5), and showing that at an impact speed of 20km/h, a pedestrian in the vast majority of cases survives impacts with a light car, whereas the probability of survival is drastically reduced with increasing speed (around 50% chance of survival at 80km/h and no more than 10% at 100 km/h). In a variety of contexts, ranging from a generalized 30 km/h zone in a city to only certain road sections in a neighbourhood, reductions in crash occurrence are statistically significant in almost all these studies (6–10).

Although the concept of 30 km/h cities has been around for many years in Europe, it’s only since 2016 with Grenoble that French metropolises have been moving in this direction, followed by Oullins in the Lyon metropolis in 2019, Bordeaux, Nantes, Lille in 2020, Paris in 2021, and most recently in the Grand Lyon metropolitan area, with the city of Lyon starting in March 2022. However, apart from a report by the Centre d’études et d’expertise sur les risques, l’environnement, la mobilité et l’aménagement (CEREMA) on an evaluation of the “30 km/h cities and towns” scheme in the Grenoble metropolitan area in 2020 (11), no studies have been published on the effectiveness of these measures in France. CEREMA reported a reduction in the number of accidents and victims, as well as in the severity of injuries (death or hospitalization) due to traffic accidents, following a generalized 30 and/or 50 km/h speed limit in Grenoble.

As in previous studies carried out in other countries, data from law enforcement organisations (BAAC in France) were used to count crash cases. However, these data under-record the slightest injuries, as well as certain modes of transport or accident configurations, particularly for vulnerable users such as cyclists, and the new motorized personal mobility devices (MPMDs) which include electric scooters. This could lead to a bias in favour of the effectiveness of the measure if crashes are reduced in severity, or concern road users with the highest rates of under-recording. It is therefore crucial to use the most exhaustive data sources possible to assess the real effect of these measures.

Finally, from a methodological point of view, there is generally a lack of detailed information on the causal factors of these reductions and the consideration of confounding factors, and in the few studies evaluating the effect of these measures in the longer term, the effect seems more mixed, with initial speed reductions not always maintained over time, and the number of collisions sometimes rising again (12,13). In recent years, it has been shown that the most commonly used models, notably difference-in-difference models, based on two time periods (an initial one before intervention, and a second one after intervention) and two groups (cases, i.e. territories with intervention, and controls, i.e. a comparison group without intervention during the second study period) to take into account the underlying temporal evolution, are often used in more complex contexts in the real life, which can bias the resulting estimates. Indeed, in the field, there may be more than two periods, with several implementation phases spread over time, or with the intervention that may not be identical in each territory (14). It is therefore necessary to use methods that take these different aspects into account to effectively estimate the effect of 30 km/h speed reduction measures.

For the purposes of this doctoral program, we will be using data from the Rhône Registry of Traffic Accident Victims, which since 1996 has been carrying out an almost comprehensive census of all accident victims in the Rhône department requiring healthcare in public or private hospitals in the Rhône or neighbouring departments. This census covers both deceased and hospitalized victims, as well as those only going to emergency rooms. In addition to the main characteristics of the accident, a precise description of the injuries and their severity, coded using the Abbreviated Injury Scale, is provided. A comparison with data from the police force, also available in the region, will be provided. Open access data from datagrandlyon will be used to complement accident data with data on 30 km/h speed limits and other variables of interest.

 

OBJECTIVES:

The main objective of the PhD project will be to assess the impact of implementing 30 km/h zones or limits in the Greater Lyon metropolitan area on accident rates.

Detailed objectives are:

1) Preparatory work on accident location will be carried out by the PhD student to improve the determination of crash locations in the database.

2) The PhD student will program in R or other statistical software to parameterize the model adapted to the context (multiple phases of intervention) over the study period (2000-2021), so that it can be applied to data from the Rhône Registry and from law enforcement agencies over the same period. Stratification by accident configuration and severity of injury will be carried out.

3) An analysis of the effectiveness of the measure in relation to the socio-economic context of the territories will be carried out.

4) An analysis of the 30 km/h city measure in the Lyon metropolitan area will be carried out. Sub-group analyses will be undertaken for accident configurations of interest, particularly those involving EDPMs.

 

Scientific, material, and financial conditions of the PhD subject:

This thesis work will be located at the UMRESTTE laboratory in Bron, under the responsibility of Sylviane Lafont and Céline Vernet. All the logistical and human resources required to carry out the work will be available in the university’s laboratories. Collaboration with the Lyon metropolitan area organization is also expected.

 

THREE-YEAR SCHEDULE:

The PhD schedule is as follows:

 

Year 1:

• State of the art of studies on 30km/h policies and intervention evaluation methods
• Preparatory work on data: improving crash location
• Implementation of the method at the IRIS scale over the period 2000-2021, based on the Rhône Registry data

 

Year 2:

• Comparison of results between the Rhône Registry data and law enforcement data
• Adapting the method to take account of the different socio-economic contexts of territories
• Preparation to apply the method to the evaluation of 30km/h city

 

Year 3:

• Evaluation of the 30km/h city measure
• Drafting of thesis manuscript

 

Doctoral school: Ecole doctorale interdisciplinaire sciences santé (EDISS 205, Lyon, France)

 

Academic research institute/University: Gustave Eiffel University (France)

 

Topics: Statistics, Epidemiology, Geomatics

 

Academic research laboratory (where the PhD candidate will work) : UMRESTTE (Epidemiological Research and Surveillance Unit in Transport, Occupation and Environment, UMR T 9405 Gustave Eiffel University, Lyon Campus  and Claude Bernard Lyon 1 University)

 

Funding information: competitive Gustave Eiffel fellowship (Gustave Eiffel PhD programme) or competitive government fellowship (EDISS).

 

Supervisory team:

Sylviane Lafont (Research director, PhD, UMRESTTE, main academic supervisor);

Céline Vernet (Researcher, PhD, UMRESTTE, second academic supervisor)

 

Start date: October 2024                

 

Duration: 36 months

 

 

Eligibility:

Highly motivated PhD candidates with statistics, biostatistics, or epidemiolocal strong skills from various backgrounds are invited to apply. We welcome applications from candidates with:

a Master’s degree, engineer diploma or international equivalent, and:

• Solid academic record and/or solid professional background in statistics, biostatistics or epidemiology
• Strong knowledge in statistical software for (big) data management and analyses (R, SAS, STATA, Python…)
• Knowledge of geomatics, cartography, geography, accidentology and/or transportation would be greatly appreciated
• Proficiency in French, English speaking and writing
• Skills in analytical thinking, interpreting, summarizing results and in scientific and academic writing in English and French
• Thoroughness and ability to collaborate and communicate with other team members and project partners
• Curiosity and appetite for research work

 

REFERENCES

1.             World Health Organization (WHO). Global status report on road safety 2023. 2023. Report No.: Global Geneva: World Health Organization; 2023.

2.             World Health Organization (WHO). Global status report on road safety 2018. Geneva: World Health Organization (WHO); 2018.

3.             Aarts L, van Schagen I. Driving speed and the risk of road crashes: a review. Accid Anal Prev [Internet]. mars 2006 [cité 8 janv 2024];38(2). Disponible sur: https://pubmed.ncbi.nlm.nih.gov/16256932/

4.             Elvik R. Effects on Accidents of Automatic Speed Enforcement in Norway. Transp Res Rec. 1 janv 1997;1595(1):14‑9.

5.             Rosén E, Stigson H, Sander U. Literature review of pedestrian fatality risk as a function of car impact speed. Accid Anal Prev. 31 janv 2011;43:25‑33.

6.             Cairns J, Warren J, Garthwaite K, Greig G, Bambra C. Go slow: an umbrella review of the effects of 20 mph zones and limits on health and health inequalities. J Public Health. 1 sept 2015;37(3):515‑20.

7.             Webster DC, Layfield RE. Review of 20 mph zones in London Boroughs. London Accident Analysis Unit (LAAU), Transport for London. TRL Publ Proj Rep. 2003;59.

8.             Grundy C, Steinbach R, Edwards P, Green J, Armstrong B, Wilkinson P. Effect of 20 mph traffic speed zones on road injuries in London, 1986-2006: controlled interrupted time series analysis. BMJ. 11 déc 2009;339:b4469.

9.             Vis AA, Dijkstra A, Slop M. Safety effects of 30 Km/H zones in The Netherlands. Accid Anal Prev. févr 1992;24(1):75‑86.

10.           Fridman L, Ling R, Rothman L, Cloutier MS, Macarthur C, Hagel B, et al. Effect of reducing the posted speed limit to 30 km per hour on pedestrian motor vehicle collisions in Toronto, Canada – a quasi experimental, pre-post study. BMC Public Health. déc 2020;20(1):56.

11.           CEREMA. Grenoble Métropole Apaisée Evaluation du dispositif « villes et villages à 30 km/h ». 2020 juill.

12.           Fisher, T. Fischer, T. 2010. Traffic Safety in Graz, Reggio Emilia. 2010.

13.           Hunter RF, Cleland CL, Busby J, Nightingale G, Kee F, Williams AJ, et al. Investigating the impact of a 20 miles per hour speed limit intervention on road traffic collisions, casualties, speed and volume in Belfast, UK: 3 year follow-up outcomes of a natural experiment. J Epidemiol Community Health. 1 janv 2023;77(1):17‑25.

14.           Callaway B, Sant’Anna PHC. Difference-in-Differences with multiple time periods. J Econom. 1 déc 2021;225(2):200‑30.

Funding category: Contrat doctoral
Concours de l’Université Gustave Eiffel ou allocation doctorale EDISS
PHD title: Doctorat en statistique, épidemiologie
PHD Country: France

Requirements
Specific Requirements

Eligibility:

Highly motivated PhD candidates with statistics, biostatistics, or epidemiolocal strong skills from various backgrounds are invited to apply. We welcome applications from candidates with:

a Master’s degree, engineer diploma or international equivalent, and:

Solid academic record and/or solid professional background in statistics, biostatistics or epidemiology
Strong knowledge in statistical software for (big) data management and analyses (R, SAS, STATA, Python…)
Knowledge of geomatics, cartography, geography, accidentology and/or transportation would be greatly appreciated
Proficiency in French, English speaking and writing
Skills in analytical thinking, interpreting, summarizing results and in scientific and academic writing in English and French
Thoroughness and ability to collaborate and communicate with other team members and project partners
Curiosity and appetite for research work

Additional Information
Work Location(s)

Number of offers available

1

Company/Institute

Université Gustave Eiffel – Site de Lyon-Bron

Country

France

City

Bron

Geofield

Where to apply

Website

https://www.abg.asso.fr/fr/candidatOffres/show/id_offre/121132

STATUS: EXPIRED