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

1) Collect and Maintain data 2) Identify hazardous locations to prioritize needs 3) Conduct engineering studies 4) Establish project priorities

Planning and analysis

1. Collect and Maintain data a) Establish Location System … where are the crashes?

- 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 – 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 • 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 4) Develop solution alternatives (counter measures) 5) Establish project priorities 6) Schedule and implement 7) Evaluate the projects

Selected issues

- Sample selection - Reference system - Adequacy of reporting procedures Select “criterion” variables (totals, rates, critical rate, weights) - Before and after studies - Proxy variable analysis

Other

Strategies: Milepost reference, Link/node, coordinate system with GIS - sections(minimum length) - spot (intersection/area) geometrics, operations, environment (sight distance, pavement, lighting) and users - Design/construction?

- Operations/maintenance?

- Driver behavior changes?

Basis: - Benefit/cost?

- Equity across jurisdictions? - Few major vs many smaller projects? Budget/Cost 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) – – – – 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