Transcript Slide 1

Highway Safety Improvement
Program
Basic Components
HSIP Basic Phases
Planning and analysis
What should we do?
Implementation
Do it.
Evaluation
Was it successful?
Planning and analysis
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2)
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4)
Collect and Maintain data
Identify hazardous locations to prioritize needs
Conduct engineering studies
Establish project priorities
Planning and analysis
1. Collect and Maintain data
a) Establish Location System … where are the
crashes?
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Milepost
Reference point
Link-node
Coordinates (GIS)
Planning and analysis
1) Collect and Maintain data
b) Types of data
Crash data
Forms and databases
Spot maps
Collision diagrams
Traffic data
Volumes, time of day
Classification
Highway system
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road types - classification
pavement type and condition
geometric conditions
photologs, etc.
Planning and analysis
2) Identify hazardous locations to prioritize
needs
Techniques to consider …
– accident frequency
– accident rate
– accident severity
– rate-quality control
– hazard index
– EB ...
Planning and analysis
3) Conduct engineering studies
a) Conduct studies to identify contributing causes
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speed studies
lane occupancy
sight distance
skid resistance
lighting
traffic control devices
school crossing studies
environment, etc.
Planning and analysis
3) Conduct engineering studies
b) Develop Countermeasures
• Evaluate cause-effect relationships
• Consider accident patterns
c) evaluate cost- effectiveness
• Crash costs
– National Safety Council
– NHTSA
– DOT, others
• Crash reduction factors (CRF) or Accident Modification Factors
(AMF or ARF)
– Many sources (with large variations)
• Cost effectiveness, B/C, ROR (rate of return), TOR (time of return),
NB (net benefit), …
Planning and analysis
4) Establish project priorities
Strategies
– ranking
– Incremental benefit-cost,
– programming
Implementation
Initiate the selected programs
- GANTT charts
- PERT
- CPM
- MSS/DSS
Evaluation
a) determine the effect of safety improvements
(crashes)
Experimental plan
• Before and after study at treatment sites
• Before and after study with control sites
• Comparative, parallel study
• Bayesian probability statistics,
• etc.
Evaluation
b) perform non-accident evaluation
• changes in speed
• changes in conflicts
• other
c) review administrative performance
• timely process?
• within budget?
Highway Safety Improvement Program
Step
1) Data Collection
2) Identify
Hazardous
locations
3) Field study of
primary sites
Selected issues
- Sample selection
- Reference system
- Adequacy of reporting procedures
Select “criterion” variables (totals,
rates, critical rate, weights)
geometrics, operations, environment
(sight distance, pavement, lighting) and
users
4) Develop solution - Design/construction?
- Operations/maintenance?
alternatives
(counter measures) - Driver behavior changes?
5) Establish project Basis:
priorities
- Benefit/cost?
- Equity across jurisdictions?
- Few major vs many smaller projects?
Budget/Cost
6) Schedule and
implement
- Before and after studies
7) Evaluate the
projects
- Proxy variable analysis
Other
Strategies: Milepost
reference, Link/node,
coordinate system with GIS
- sections(minimum length)
- spot (intersection/area)
Research on crash reduction
factors (CRFs)
Tools: operations research
models such as linear,
integer or dynamic
programming?
Are changes due to
regression to the mean?;
Are proxy variables relevant
related to safety
improvement?
Federal (FHWA) Highway Safety
Improvement Program
• Core program of SAFETEA-LU
• Separately funded (Section 148)
• Requires Strategic Highway Safety Plan (SHSP)
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ID and analyze problems/opportunities
ID projects and strategies
Evaluate accuracy of data
Prioritize improvements
• Hazard Elimination Safety (HES) program
– section 152
• High Risk Rural Roads (HRRR) program
• Rail-Highway Grade Crossing program
– Section 130