2005 Traffic Records Forum

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2005 Traffic Records Forum

• How WSDOT Does Collision Data Analysis and How It
  Influences Our Safety Investments

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Washington State Dept. of TransportationTranspor
tation Data Office(TDO)

• Roger E. Horton
• HortonR_at_wsdot.wa.gov

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State Wide Collision Data
Annually, the Collision Data Branch processes
more than 140,000 collisions.
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Collision Data
In the average two-vehicle collision, more than
160 data items are collected.
Collision data helps guide the annual investments
in roadway safety improvements made by WSDOT (50
- 100 million).
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Statewide Collision Data
How are collision reports processed?

• Collision reports are received daily at the TDO
• Reports are scanned and indexed
• Collision images are available for Public
  Disclosure and maintenance/operation staff within
  24 to 48 hrs

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Statewide Collision Data
How are collision reports processed?

• Jurisdiction is determined
• Collision reports are analyzed and entered into
  the Collision Location and Analysis System
• Reports are checked by Quality Assurance for
  accuracy

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Statewide Collision Data
How are collision reports accessed?

• Access is available on line to the collision
  report images by WSDOT, WSP soon counties
• Can search collision report database by primary
  roadway, date range, and county within 2 days of
  report being received
• Can search by specific location within 2 months
  of collision

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Data Marts at the Transportation Data Office

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What is a Data Mart?

• A data mart is a database designed to help
  managers make strategic decisions about their
  business.

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What is the benefit of having a Data Mart?

• A data mart allows analysts to easily perform
  their own queries and generate reports against
  their data without requiring their IT dept to
  write code to do this. (Customers dont want to
  wait for IT to write a report, and IT doesnt
  like developing code for reports)

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How does the structure of a Data Mart differ from
that of a typical (transactional) database?
Data Marts
The database structure of a data mart is tuned
for querying (getting the data out) vs. tuning
for data entry (putting the data in)
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Data Marts

• What Data Marts are Available at the TDO?

• Collision Data Mart
• Roadway Data Mart
• Traffic Data Mart

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Collision Data Mart
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Collision Data Mart(State, City, County other)

• Has a user interface which allows customers to
  quickly access a set of canned reports
• Customers have on-demand access directly to the
  database through the use of Hyperion to make
  their own queries.
• Results of queries may be saved as data or charts
  and exported for distribution through e-mail or
  to the web.

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Roadway Data Mart(State Highways only)

• Functionality similar to the Collision Data Mart
  (i.e. reports and access to the database
  directly)
• This data mart contains information about roadway
  geometrics (number of lanes, lane width,
  horizontal and vertical curvature, roadway
  composition, speed limits, lane usage, functional
  classification, median width, type protection
  and ..)

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Traffic Data Mart (State Highways only)

• Functionality similar to the Collision and
  Roadway Data Marts (i.e. reports and access to
  the database directly)
• This data mart contains information such as
  traffic volume, vehicle classification, weight
  and speed.
• The speed information is shared with WSP through
  the 100 MPH Club report.

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Data Marts

• Joining all three data marts can answer questions
  such as
• Do roadways with a speed limit of 55 mph have a
  higher fatality rate (per hundred million vehicle
  miles) than those that have a speed limit of 65
  mph?
• (how long would it take you to answer such a
  question using your systems)?

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Safety at WSDOT
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Safety is Everyones Responsibility At WSDOT

• No single office has responsibility
• Direction is guided by the Highway Safety Issues
  Group (HSIG)
• The HSIG gives guidance to planning, programming,
  design and operational decisions through a team
  approach
• HSIG membership includes HQ and regional traffic
  and design engineers, system planners and program
  management

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HSIG Objectives

• Provide leadership guidance
• Provide a forum for discussion
• Work cooperatively with multiple disciplines to
  improve safety
• Promote highway safety as a top departmental
  policy

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HSIG Objectives

• Identify areas for improvement
• Develop recommendations for the Highway System
  Plan, Design Manual, Traffic Manual Programming
  Instructions
• Optimize the use of highway safety resources
• Minimize the societal cost of collisions

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WSDOT Collision Data Usagefor State Highways

• Safety deficiency analysis of state highways
• Maintenance Operations guides low cost
  enhancement subprogram corridor safety program
• Used in benefit/cost analysis in our project
  prioritization processs both mobility and
  safety subprograms

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WSDOT Collision Data Usagefor State Highways

• Supports statewide safety initiatives
• Project development even simple repaving
  projects
• Design standard modifications
• Supports deviation from design standards on
  reconstruction projects

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WSDOTs Budget Structure (Colored boxes use
collision data)
Maintenance Operations
Low cost enhancements
Snow Ice Program
Corridor Safety Program
Other
Preservation
Structures
Pavements
Other Facilities
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WSDOT Safety Deficiency Analysis

• Three types done every other year
• High Accident Locations (HALs)
• High Accident Corridors (HACs)
• Pedestrian Accident Locations (PALS)

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High Accident Locations(HALS)

• Uses 2 years of historical accident data
• Analyzes 0.1 mile segment, every 0.01 mile
• Criteria used is total severity points and
  severity points per million vehicles per year
  (severity rate)
• Severity points are
• 1 property damage only
• 3 possible injury
• 5 evident injury
• 9 disabling injury
• 10 fatality

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High Accident Locations(HALS)

• Six types of highways are analyzed separately,
  and an average severity rate is calculated for
  each type
• 1) rural, full access control
• 2) rural, 2-lane without full access control
• 3) rural, 4-lane without full access control
• 4) urban, full access control
• 5) urban, 2-lane without full access control
• 6) urban, 4-lane without full access control

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High Accident Locations(HALS)

• If an analysis unit has 6 or more accidents with
  10 or more severity points it is labeled a Severe
  Accident Location (SAL)
• All SALS in each highway type are then compared
  statistically against the average severity rate
  for that type

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High Accident Locations(HALS)

• All SALS whose severity rate is above one
  standard deviation of the severity rate for that
  type of highway are designated HALS
• In addition, any analysis unit that has 2 or more
  fatal accidents is also designated as a HAL,
  regardless of its severity rate

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High Accident Corridors(HACS)

• Looks for continuous accident problem areas
• Uses 5 years of historical accident data
• Analyzes 1 mile segment every 0.5 miles
• Six types of highways are analyzed separately
  (see HAL process)

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High Accident Corridors(HACS)

• Criteria used is- Total severity points per
  mile- Total accidents per mile- Severity points
  per accident per mile
• If a section is above the average of all three
  criteria for the highway type it is considered a
  HAC.

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Pedestrian Accident Location(PALS)

• 6-year collision history
• Requires 4 pedestrian collisions (first harmful
  event) within a 0.10 mile section
• Began in 1996 - of 75 identified PALs, 25 were
  State responsibility
• Locations are frequently 5 lanes at bus stops or
  fast food outlets with business district adjacent
  to residential

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HAL, HAC, PAL Review

• Each of the 6 WSDOT Regions review each of the
  ranked deficiency lists.
• Decisions are made as to how best to improve
  safety at each location
• Budget limitations are always a factor
• Can a low cost enhancement work or does it need a
  larger safety project, or is it a mobility
  solution?

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Operations Low Cost Enhancement Program

• Is developed out of the HAL, HAC PAL reviews
  and citizen or maintenance requests
• Usually projects are under 50,000 and done with
  WSDOT maintenance staff
• Very little engineering or environmental work
  needed
• Idea is to respond quicker than a full standards
  based construction project can

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2001-2003 Biennium                              
                                                  
                                                  
                                                  
                                  
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Corridor Traffic Safety Program

• Low-cost, near-term solutions (usually very minor
  infrastructure improvements)
• Uses partnerships with community groups,
  business, engineering, enforcement, education,
  and emergency services organizations.
• The program is locally led and coordinated in
  each community.

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Corridor Traffic Safety Program

• A corridor is selected based on two things
• There is statistical evidence that a section or
  set of roadways has a significant crash problem.
• There is energy on the local level to undertake a
  corridor project.

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Basic Design Levelfor Paving Projects
(non-interstate)

• Replace pavement markings
• Replace deficient delineation and signing
• Restore existing right of way fencing
• Ensure previous sight distance has not been
  reduced
• Adjust guard rail to maintain design height
• Upgrade guardrail ends and bridge end protection
• Replace rumble strips
• Adjust and/or modify drainage features
• Spot safety improvements review collision data

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Improvement Safety Subprogram

• 1. High Accident Locations (HAL)
• 2. Pedestrian Accident Locations (PAL)
• 3. High Accident Corridors (HAC)
• 4. Signals and Channelization
• 5. Interstate Safety
• Improve the geometrics of the Interstate.
• Projects are programmed based on B/C analysis
  of standards based solution to all deficient
  sections one standard deviation above region
  societal cost average

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Improvement Safety Subprogram

• 6. At-Grade Intersections
• Eliminate major at-grade intersections on
  multi-lane, divided highways with speeds of 45
  MPH or greater.
• 7. Risk Reduction
• Improve roadways where geometrics, traffic
  volumes, and speed limits indicate a high
• accident potential by instituting standards
  based highway safety solutions. Based on
  principles in AASHTOs Roadside Design Guide, 1989

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Improvement Safety Subprogram

• 8. Pedestrian Risk
• Proactively address pedestrian safety along
  state highway segments that exhibit high
  pedestrian use and the potential for future
  accidents.
• 9. Safety Initiatives
• Address highway safety through statewide
  low-cost, high benefit and short-term projects.

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Benefit/Cost Analysis Within WSDOT

• Types
• Uses
• Tools

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Benefit/Cost Analysis

• Two types used within WSDOT.
• Collision Reduction - Historical Data.
• Collision Prevention - Predictive.
• Both methods used to compare current vs. future
  conditions for alternatives.

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Benefit/Cost Analysis Types

• Collision Reduction - Historical Based.
• Location/Section Specific.
• Utilizes existing numbers of collisions and
  associated severity.
• Reduction Factor is a User Input.

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Benefit/Cost Analysis Types (cont.)

• Collision Prevention - Predictive.
• Estimates number of encroachments based upon
  geometric features.
• Evaluates future geometric conditions vs.
  existing conditions.
• Roadside severity rating is a user input.

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Benefit/Cost Tools

• Collision Reduction Worksheet.
• Collision Prevention Worksheet.
• Roadside Design Guide.
• Roadside Model.
• Counter Measures Booklet.
• HQ Support.

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Benefit/Cost Uses

• Systematic Prioritization (I2).
• HALs, HACs, PALs, RISK, At-Grade Removals.
• Evaluation of Corridor Design Standards.
• Lane or Shoulder Width, etc.
• Evaluation of System-Wide Standards.
• Rumble Strips, Median Widths, Bridge Rail
  Upgrades, cable barrier placement, etc.

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Benefit/Cost Uses (cont.)

• Evaluation of optional Preservation Safety.
• Justification supporting deviations from
  standards.
• Off/On Ramp Tapers, I/S Angle, etc..

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Roadway improvements that have B/C gt 1.0 prove
effective in reducing crashes.
One of the most important specific treatments has
been cable median barrier installation.
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Although fatality rates are declining, fatalities
are still unacceptable.
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For More Information About the Transportation
Data Office
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TDO Products and Services Pamphlet
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TDOs Web Location

• www.wsdot.wa.gov/mapsdata/tdo/default.htm

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Other Transportation Data Office Products
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SRview 2.0/360º
System that uses digital cameras to capture
images every 0.01 mile looking straight forward,
at 45º angle, and 360 º
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Video Van
360º Camera
Front View Camera
Side View Camera
360º Camera
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SRweb 2.1
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Types of Data Available at the TDO

• Highway digital pictures front, side, 360
• Highway Roadway data
• Highway Traffic data
• Collision data for all roadways
• Functional Class data for all roadways
• Federal Highway Performance Monitoring System
  (HPMS) data for the state
• Highway Roadside Features Inventory business
  plan development stage

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Type of Roadway Data Available

• State Highway Log roadway, shoulder median
  width, of lanes, speed limits, intersection
  locations,
• GIS Road Log abbreviated version of above
• Road Life Report Contract Data
• Horizontal and Vertical Alignment Report Curve
  Data
• Roadway Classification Log Jurisdictional Data

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Traffic Data Available

• Hourly Traffic Volume
• Average Daily Traffic (ADT) (also available -
  average weekday, average weekend day and annual
  average day)
• Vehicle Classification (type of vehicles in 4 or
  13 categories)
• Truck Percentages

• Vehicle Weight
• Vehicle Speeds
• Design Hour Factors
• (K and D)
• Traffic Flow Maps
• Vehicle Miles Traveled (VMT)
• Factors (Axle Correction, Seasonal Adjustment,
  Day of Week Adjustment)

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Highway Usage Data Branch Major Products

• Published Reports
• Annual Traffic Report
• Automated Data Collection (ADC) Site Monthly
  Report
• ADC Selected Site Quarterly and Annual Speed
  Reports
• ADC Site Annual Peak Hour Report
• Reports and Guides Available Upon Request
• Traffic Monitoring System for Highways
  Guidelines
• Hourly Traffic Volume Reports
• Hourly Traffic Classification Report
• ADC Site Vehicle Classification Report
• ADC Site AM/PM Traffic Volume Summary Report