Title: Network safety management NSM Analysis of black spots
1Network safety management (NSM) Analysis of
black spots
Cyprus December 2008
- Herman J. Moning MSc.
- Rijkswaterstaat - Centre for Transport and
Navigation - The Netherlands
2Overview Eur Dir PPChecklists
Planning process
European Directive
Schemes/ checklists
Method RSIA
RSafety
Impact Assessm
Guidelines checklists
Global design
RS Audit Global design
Guidelines checklists
Detailed design
RS Audit Detailed design
Checklists
Construction
RS Audit Pre-opening
Checklists
Road in operation
RS Audit After opening
Method of Inspection
RS Inspection
Network Safety Mgt
Maintenance
3Presentation (NSM) Black spots
Planning process
European Directive
Schemes/ checklists
Method RSIA
RSafety
Impact Assessm
Guidelines checklists
Global design
RS Audit Global design
Guidelines checklists
Detailed design
RS Audit Detailed design
Checklists
Construction
RS Audit Pre-opening
NSM Black spots
Checklists
Road in operation
RS Audit After opening
Method of Inspection
RS Inspection
Network Safety Mgt
Maintenance
4Content Black spot analysis
- What prescribes EU-directive (October 2008)?
- Experience from The Netherlands
- Process to analyse Black spots
- What to do tomorrow in Cyprus?
5NSM-definitions (EU-directive)
- Identification of high accident concentrations
sections - at least the fatal accidents in previous years
per unit of road length in relation to traffic
flow and in case of intersections, the number of
such accidents per location of intersections - Identification of sections in NSM
- takes into account their potential savings in
accident costs. For each category of roads, road
sections shall be analyzed and ranked according
to safety factors, like accidents concentrations,
traffic volume and traffic typology - Priority list of road sections where an
improvement of infrastructure is expected to be
highly efficient
6Content Black spot analysis
- What prescribes EU-directive (October 2008)?
- Experience from The Netherlands
- Process to analyse Black spots
- What to do tomorrow in Cyprus?
7Definitions (Dutch)
- Black spot an intersection or a short road
section with a high number of road accidents with
casualties - Dutch criterion 6 or more killed or injured
persons in three successive years - High risk sites an intersection, a road section
or area with a high number of accidents with or
without casualties - Dutch criterion 12 accidents or more, but less
than 6 killed or injured persons in three
successive years - High risk figures sections with a high risk
figure more than the average value
8Road safety map Province Utrecht
9Manual analysis of high risk locations
- Dutch Manual Analysis Traffic Accident
Concentrations (MATAC, 1979) - Subsidizing experiments by the Ministry (1981)
- stimulating the use of the manual
- gathering knowledge and experience (143 locations
were evaluated) - results were published by CROW (1993)
10Results research / evaluations
- Evaluation (3 years before and after)
- in average 32 reduction in accidents
- reduction in accidents with injured 45
- 50 of locations the reduction in accidents is
not significant - Effects depend of the quality of analysis
- incorrect interpretation of results
- deviate from main process or the connecting
thread - Infrastructure measures are most effective
- reducing speeds
- less sensitive for violations
11Recommendations
- Analysis of high risk sites of great value to
improve road safety - Reconstruction / maintenance works always
perform an analysis of accidents - After a serious accident many opinions
- risk that measures do not solve the problem(s)
- risk that investments are higher than necessary
- Measures should be based on thorough, objective
analysis of the problem(s) POGSE - Prevent is better than cure sustainable safety
12Example left turning lane
13Approach of road safety
14Objectives accident analysis
- To draw conclusions from similarities in accident
characteristics in order to improve the design or
use of that location or section - Investigations into main causes of accidents
- human factors 95
- road factors 18
- vehicle factors 6
- Good, uniform design simplifies the driving task
- Design of infrastructure influences behaviour
- Behaviour is not only enforced by law (more or
less remaining free) but actually enforced by
infrastructure
15New, revised manual (1992)
- To revise the old manual
- To tackle scattered accidents
- Manual analysis of high risk sites, sections or
areas - In total 5 parts
- 1 Selection of high risk sites
- 2 Reference figures
- 3 Analysis of high risk locations (MATAC)
- 4 Analysis of high risk sections or areas (MASA)
- 5 Analysis of special groups in areas (MAGA)
16Selection of locations
- List of all locations
- threshold 5 accidents in three successive years
- Clear the list
- changed road functions
- recent reconstructions
- Possible weight factors
- Killed 5
- serious injured 3
- slight injured 1
- material damage 0,5
17Essence of analysis
- Every accident is unique
- more or less coincidence of circumstances
- every accident has its own chain of preceding
events - mostly more than one possible cause can be
indicated - Circumstances or failure chances directly
preceding the collision moment - In practice also similarities between accidents
- Analysis focuses mainly on the failure chances in
the situation directly preceding the moment of
collision
18Accident scheme
19Data available
- Registration of accidents is incomplete (NL)
- killed 94
- injured, hospital 60
- injured, first aid 16
- slightly injured lt 16
- only material damage ltltlt 16
- Data every accident is limited. No insight into
the entire preceding chain of events. Many
details are not known and not recorded - Data is solely based on conclusions of the duty
police officer after the accident
20Application accident analysis
- All (recorded) accidents / collisions
- Minimum number of accidents
- with small number great chance incidental factors
are (partly) determinant - ? 10 accidents in 3 - 5 successive years
- ? 5 accidents in 3 - 5 years with a similar
characteristic - a practical lower limit reliability of results
- Locations
- all kinds of intersections
- road sections
21Content Black spot analysis
- What prescribes EU-directive (October 2008)?
- Experience from The Netherlands
- Process to analyse Black spots
- What to do tomorrow in Cyprus?
22Process
no
yes
yes
no
23Step 1 collect data (1)
- Accident data (3-5 years preceding the study)
- Traffic data
- existing or foreseen road function
- traffic volumes (short cut)
- specific group of road users
- Drawing of the location (1 500)
- reconstructions
- Additionally data
- speed data
- experience police
- complaints residents
24Step 1 Processing data (2)
- Systematically sorting of data
- keep overview
- keep main process or continuous thread
- Use work sheets
- manoeuvre worksheet
- accident scheme
25Step 1 Manoeuvre work sheet
26Step 1 Manoeuvre work sheet (example)
27Step 1 Accident scheme
28Step 1 Accident scheme
29Step 1 Accident scheme (2)