1. Road traffic accident analyze aggregation in spatial and time
Pavel Hrubeš, Ing. Ph.D.

2. Accident reports and analyzes purposes
Government, legal policy makers
Road maintainers, traffic engineers
Integrated rescue systems (police, fire dept., EMS)
Space and time resolution
Country/Union
District/Region
Municipality/ Local zone
Years/decades
Country target plans
Country comparison
District target plans
Budget allocation
District comparison
Black spot identification/ Local measure
Months and Weeks
Policy makers, measure
Season trends
Preventive actions
Days, Hours and Minutes
Operation plans
Czech Technical University in Prague - Faculty of Transportation Sciences
Department of Control and Telematics

3. Space of analyzes - accident description
Year, Quarter, Season, Month, Week, Weekday Day, etc.
Easter, Holiday, Christmas
GIS related information's
Weather measurement (wind, rain, fog etc.)
Special occasions (football matches, concerts ),
Socio-demographics data (population, count of drivers, male, female, age of drivers etc.
Road system data (statistical length of roads, curvature)
Law and driving rules changes
Car systems data (CAN)
Type and Cause of Accident,
Count of Deaths, seriously or slightly Injuries
Car Type and make of car
Alcohol, Seat belts
Weather condition
Sight situation
Descriptive information
Time
Accident
Coordinates,
Country, State, Region, City, Village, etc.
Road, Crossroad or Street Number
Type of Road or Crossroad
Direction of driving
Location
Czech Technical University in Prague - Faculty of Transportation Sciences
Department of Control and Telematics

4. Methods of analyze and issues
Aggregation
Time and spatial inf.
Density estimation, ranking
Cluster analyze
Spatial and descriptive inf.
Estimation of accident frequency
Time (spatial selection)
Small area estimation problem/disease mapping problem
Many attributes, no known relevance and significance to analyze
How to compare, sort, present, etc.

5. Accident severity index
ASIn Accident Severity Index of n-th accident
K number of persons killed
SI number of seriously injured
SL number of slightly injured
M material damage estimation
W.. weight of component
C scale constant
… other components
Traditional cost function
Accident Cost= K * Kcost + SI * SIcost + SL * SLcost + …

6. Aggregation – usual functions
Sum of ASIn
Sum of several ASI is almost equal to accident count.
Average of ASIn
Average of ASI aggregation shows ratio of accident’s severity to the count of accidents.
Multiplication of ASIn
Multiplication of several ASI for light accidents is also close to the one and grows very slowly opposite to the multiplication of ASI for serious accidents which grows faster.
Color scale of aggregated ASI
good/better
average/static
poor/worse

7. Aggregation of ASI in Time

8. Aggregation of ASI in Time

9. Aggregation of ASI in Time

10. Aggregation of ASI in Time

11. Aggregation of ASI in Time

12. Aggregation of ASI in Time

13. Aggregation of ASI in Time
Month
SUM, AVG and Multiplication ASI 2008
Day in the Month

14. Aggregation of ASI in space

15. ASI computation and aggregation
Conclusion
ASI computation and aggregation
Simply control of analyze by adding components and modification of its weights
Very simply implementation in relational databases and GIS
Summary of ASI enable simple selection, sorting and presentation
ASI could be useful by other methods of accident analyze as the input. (weighted density estimation, etc.)

16. Thank you for attention.
Acknowledgment
I gladly thank to Col. Josef Tesařík and Petr Sobotka from Directorate of Traffic Police, Branch of the Police Presidium of the Czech Republic which kindly provide me the official road accident data for years 2007 and 2008.
Ing. Pavel Hrubeš, Ph.D.
Czech Technical University in Prague
Faculty of Transportation Sciences
Department of Control and Telematics
Konviktska 20, Prague 1,
Czech Republic
Web:
Tel.: (+420)
Czech Technical University in Prague - Faculty of Transportation Sciences
Department of Control and Telematics