Gdansk, , Gdynia ia, Sopot Ruth Bergel-Hayat(*) Wojciech Kustra, - - PowerPoint PPT Presentation

In Incle lement weather effect on road casualties in in urban areas: : the case of the metropolitan area Gdansk, , Gdynia ia, Sopot

Wojciech Kustra, Joanna Zukowska

Highway & Transportation Engineering Department Faculty of Civil & Environmental Engineering Gansk University of Technology, Poland

ICTCT workshop, Olomouc, Czech Republic, October 26-27th, 2017 “Traffic safety and the City" - How to enhance traffic safety and liveability in urban areas? ________________________________________________________________________


Ruth Bergel-Hayat(*)

RBH Conseil & Formation, France

Nathalie Focant

VIAS Institute, Belgium

__________________________________________ (*)University Paris-Est, IFSTTAR GRETTIA for a part of the work

Plan of the presentation

• 1. Context of the research
• 2. Tricity metropolitan area
• 3. Casualty data
• 4. Inclement weather data
• 5. Modelling
• 6. Model’s outputs
• 7. Discussion
• 8. Conclusion
• 9. References

26th _27th October 2017 2 Inclement weather and Road Safety in urban areas - ICTCT Workshop in Olomouc, Czech Republic

The context

• The relationship between weather conditions and road safety outputs has been questionned in

2010 (specially cold spells over Europe)

• Researchers invested this topic intensively (SafetyNet, 2004-2008)
• The IRTAD group of OCDE initiated a formal reflexion for analysis and short-term forecasting

purposes (from 2014 onwards)

• The emergence of the reflexion about road safety and cities leads to raise this question for urban

areas.

26th October 2017 3 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

Tricity

Gdansk – 464.000 inhabitants 262 km2 Sopot – 37.500 inhabitants 17,3 km2 Gdynia – 245.000 inhabitants 135 km2

26th October 2017 4 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

Casualty data

• Road safety data for Gdansk-Gdynia-Sopot Metropolitan Area has been extracted from

the Polish Police Database

• The casualty numbers, for drivers+passengers, are disaggregated according to :
• the severity (killed and serious injuried, slight injured);
• the user type ( VRU among which pedestrians mainly, vehicle users among which

car users mainly)

• For the period 2000-2005, the total of victims in cars was uncomplete but this could be

successfully corrected.

26th October 2017 5 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

26th October 2017 6 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

Casualty data

26th October 2017 7 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

Casualty data

Total number of victims: Disaggregation by severity type: 96,4% are injured,:slight injured (85,7%), seriously injured (10,69%), 3,6% are fatalities Disaggregation by road user type 48,4% are VRU: Pedestrians (34,4%), bicyclists (9,3%) and motorised 2 wheelers (4,6%) 51,6% are Vehicles: Car + lvc users (45,9%), hvl (1,5%), Bus + Trolleys (2,8%), Trams (1,2%)

Inclement weather data

• The weather data have been gathered from the Agri4cast website
• The weather data are measured by grids
• The center of grid nr 118132 with Latitude 54,30 and Longitude 18,70) is the nearest

grid center to the Tricity (Gdansk itself having Latitude 54,37 and Longitude 18,63)

• The weather data, averaged over all grid centers in Poland, are used for measuring the

average weather for the whole of Poland

26th October 2017 8 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

Weather data: 3 types of days with inclement weather

26th October 2017 9 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

rainy and cold days (13%) , dry and cold days (13%), rainy and warm days (33%), and normal days (41%)

33% 33% 13% 16% 13% 14% 41% 37% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Gdansk/Tricity Poland normal dry_cold rain_cold rain_only

Modelling

• State space methods
• A locally linear trend (stochastic level and slope) and seasonal
• Dependant variable: Number of victims in the month;
• Independant (explanatory) variables: numbers of 3 different types of days with

inclement weather in the month;

• With interventions
• On a monthly basis (January 2000 - December 2016)
• Main output
• Independant variables coefficients’ estimates (3 per model)
• Using Stamp (in Oxmetrics)
• or other softwares (such as the SAS system, proc UCM)

26th October 2017 10 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

Model’s output: Tricity

26th October 2017 11 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

• 8%
• 7%
• 6%
• 5%
• 4%
• 3%
• 2%
• 1%

0% 1% 2% Lvictims LvictimsCARS LvictimsVRU LvictimsPed LvictimsBic LvictimsMot rain_cold dry_cold rain_only

Model’s outputs: All cities in Poland

26th October 2017 12 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

• 8%
• 7%
• 6%
• 5%
• 4%
• 3%
• 2%
• 1%

0% 1% 2% Lvictims LvictimsCARS LvictimsVRU LvictimsPed LvictimsBic LvictimsMot rain_cold dry_cold rain_only

Model’s outputs: estimates’ interpretation - Tricity

26th October 2017 13 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

• A rainy and cold day is linked with:

a decrease in the numbers of victims in the month, regarding the total of VRU

• A dry and cold is linked with:

a decrease in the numbers of victims in the month, regarding the total of VRU

• A rainy day without cold is linked with:

a decrease in the numbers of victims in the month, regarding the total of VRU a increase in the numbers of victims in the month, regarding car users Unfortunately, no estimates could be computed regarding each type of VRU.

Model’s outputs: estimates’ interpretation - all cities in Poland

26th October 2017 14 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

• A rainy and cold day is linked with:

a decrease in the numbers of victims in the month, regarding all VRU: pedestrians, bicyclists and motorized 2W (-1%, -7% to -8% resp.)

• A dry and cold day is linked with:

a decrease in the numbers of victims in the month, regarding all VRU: pedestrians, bicyclists and motorized 2W ( -1,5%, -4% to -6% resp.)

• A rainy day without cold is linked with:

a decrease in the numbers of victims in the month, regarding 2 Wheelers: bicycles and motorized 2W ( around -2% each) a increase in the numbers of victims in the month, regarding pedestrians (+0,8%) and also, but less significantly regarding car users (+0,4%).

Discussion

• Choose between estimates’ significancy and data disaggregation
• Significant coefficients’ estimates can only be provided by aggregate (Gaussian) models when

the victim numbers are large enough

• Other models are more appropriate for disagreggated victim numbers
• Choose according to the final aim
• Analysis of inclement weather impact on specific victim types data
• Analysis of (aggregated) weather impact on aggregated victim data
• Analysis or correction for the weather impact ?

26th October 2017 15 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

Conclusions

• The significant results highlight the relevance of taking 3 inclement weather

configurations into account in road safety trend analysis.

• Information related to rain, snow and frost, appropriately aggregated at urban area-level

and at the scale of the month, enrich the short-term trend analysis performed at the monthly level.

• A relevant output of the analysis is that it provides correlations between weather

variables and types of road user's casualty variables aggregated at urban area-level.

• The work done on the Tricity area provides comparisons with the total of casualty

variables in urban areas in Poland.

26th October 2017 16 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

Outlook

• Comparisons not only on other (the total of ) casualty datasets in urban areas in Poland

but also on the same type of road user's casualty datasets in urban areas in other countries.

• These results could serve to improve road safety management (alert levels by inclement

weather are to be set), and to improve road safety trend assessment as well (short-term changes in the trend, due to atypical inclement meteorology are to be corrected for, which highlights the changes imputable to other factors such as road safety policies).

26th October 2017 17 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic

Some more information ?

• A very large number of papers on the topic ‘Weather and road safety’:

Among which: Bergel-Hayat, R., Debbarh, M., Antoniou, C., Yannis, G. (2013) Explaining the road accident risk: Weather effects. Accident Analysis & Prevention nr 60, 456-465. Bergel-Hayat R., Zukowska J. (2015) Road safety trends at national level in Europe: a review of time-series analysis performed during the period 2000-2012. Transport Reviews: A Transnational Transdisciplinary Journal. 35(5), 650-671

• Factsheet N° 3 of the IRTAD Forecasting Subgroup, chaired by Klaus Machata (KfV,

Austria)

Bergel-Hayat, R., Focant, N. (2017) Inclement weather effects on road casualty at national level- Methodology and application to a number of European countries. 6th IRTAD Conference, 12 October 2017, Marrakech, Morocco

Thank you for your attention !

26th October 2017 18 Inclement weather and Road Safety in urbain areas - ICTCT Workshop in Olomouc, Czech Republic