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Bicycles/Pedestrians

Safety Toolbox: Problem identification

Where to look

There are numerous sources of relevant data for collision analysis ranging from the detailed collision reports themselves to public health databases, which can yield information pertaining to what happens to victims after a collision has occured. There are also several on-line resources that provide querying capabilities for comparative analyses. In this section:

Traffic collision databases


Police/sheriff and public works department databases

Public health databases


Other Sources of Data

Traffic collision databases


Statewide Integrated Traffic Records System (SWITRS). Maintained by the California Highway Patrol (CHP), Caltrans, and the California Department of Motor Vehicles (DMV), and contains data on all reported vehicle crashes in California that occur on a public roadway. SWITRS serves two purposes: to collect collision data from all California traffic enforcement agencies for use in statewide and regional analyses and to provide local agencies with quarterly and annual summaries of their collision data. There is a processing delay of three to six months between the end of a reporting period and the availability of the summary reports from CHP.

CHP provides collision data in a format suitable for direct importing into programs such as MS-Excel, consisting of three worksheets containing collision summary data, party data, and victim data, related by a unique case ID (SWITRS Raw Data Format). To request SWITRS data, contact Roberta Tanger, CHP Information Services Unit, at rtanger@chp.ca.gov or 916-375-2849.

Latest SWITRS Annual Report. SWITRS Annual Reports are available on-line from 1997 on. For pedestrian and bicyclist-involved collisions, the most relevant summaries are contained in Section 4 — Victims and Section 7 — Short Subjects.

Traffic Accident and Surveillance Analysis Systems (TASAS). State highway related collision reports receive additional coding in SWITRS as to objects struck and location details. Caltrans receives this State highway related data on a weekly basis for the Traffic Accident Surveillance and Analysis System (TASAS). The data transmitted to Caltrans does not contain names, drivers license numbers, addresses, vehicle license numbers, or data on age and sex of drivers and victims. TASAS has an accident data base (AXDB), linked to a highway data base (HDB) which contains description elements of highway segments, intersections and ramps, access control, traffic volumes and other data. For more information, contact Richard Haggstrom, Caltrans Pedestrian and Bike Safety Branch, at richard.haggstrom@dot.ca.gov or 916-654-6600.

Fatality Analysis Reporting System (FARS). Maintained by the National Highway Traffic Safety Administration (NHTSA) and contains data on all reported vehicle crashes in the United States that occur on a public roadway and involve a fatality. The FARS Query System provides interactive public access to fatality data through the web interface. FARS is compiled from collision reports and death records and provides many details on fatal traffic collisions, including location by street name and intersection. The following information is readily available by state and by year (from 1994 to 2003). Users may also create their own customized queries.

Pedestrians

  • Pedestrians Killed, By Age and Location
  • Pedestrians Killed, By Time of Day and Day of Week
  • Pedestrians Killed in Single Vehicle Crashes, by Vehicle Type and Initial Point of Impact
  • Pedestrians Killed, By Related Factors (roughly equivalent to SWITRS primary collision factors)

Bicyclists

  • Pedalcyclists Killed, By Age and Location
  • Pedalcyclists Killed, By Time of Day and Day of Week
  • Pedalcyclists Killed in Single Vehicle Crashes, by Vehicle Type and Initial Point of Impact
  • Pedalcyclists Killed, By Related Factors (roughly equivalent to SWITRS primary collision factors)

 

Traffic Collision Reports (CHP 555) and Local Collisions Databases. A collision report form captures information about a collision, the reporting officer and agency, one or more Parties (drivers, bicyclists, device operators, or pedestrians), and zero or more Victims (if anyone was injured or killed). Collision data are entered on a California Highway Patrol (CHP) 555 form or 555-03 short form. The short form may be used if there are no more than two parties and there are no injuries. (Blank CHP 555 Form, ~6.8 Mb )

Collision reports have two parts — summary sheets and detail sheets. Summary sheets capture information about the collision location, date, time, conditions, violations, and the reporting agency and officer. Detail sheets capture statements from the parties (if available), victims (if any), and witnesses (if any), plus the officer's interpretation of what occurred, including a sketch diagram showing how the vehicles, devices, and/or pedestrians interacted and where the impact(s) occurred.

To improve reporting accuracy and save time at the scene, police departments pre-draw "factual diagrams" of intersections within their jurisdiction. These diagrams show the orientation, curb lines, width, and layout of each intersecting street. Originals and photocopies are kept in a file at the office; copies are used when a collision occurs at or near a particular intersection.

Enforcement agencies typically file collision records by case number — a unique numeric ID produced by the agency's dispatching system and also used by the case management system. Computer-aided dispatching systems are known as CADs or CADDs; case management systems as CMSs. In most local agencies, copies of the collision reports are also kept by the traffic engineering department or division for use in collision analysis to identify engineering countermeasures. Records kept by engineering are usually filed by street name and cross street.

The procedure for completing and processing collision reports is defined in the CHP Collision Investigation Manual ("CIM"), Publication HPM 110.5. A police officer fills out the collision report at the scene, either on paper or using a laptop or handheld computer. The report is checked by a superior officer at the responsible enforcement agency (city police department, county sheriff department, or CHP office). If coding errors are found the reporting officer corrects the report. If the enforcement agency keeps its own database of traffic collisions, data from the corrected report is entered. The summary sheets from the corrected collision reports are sent to CHP's Information Services Unit in Sacramento, where the information is entered into SWITRS. CHP data entry staff may correct minor coding errors, and if a report of a complex collision actually represents two or more collision events they may generate additional collision report records accordingly.

Most of the information from CHP 555 forms that is entered into SWITRS is from page 2 of the form, which contains data regarding the primary collision factor, roadway conditions, movements preceding the collision, impairment of any of the involved parties, etc. For additional clarification on what is covered under each field, refer to Chapter 4 of the CIM: Instructions for CHP 555 Page 2, >15 Mb.

California Office of Traffic Safety (OTS). Using annual SWITRS data, the OTS provides collision rankings by California city and county of the number of victims killed and injured in traffic collisions, including the total number of pedestrians and bicyclists, pedestrians and bicyclists less than 15 years of age, and pedestrians 65 years of age or older. OTS also categorizes cities and counties by groups in terms vehicle miles of travel and population within a jurisdiction, and based on the number of victims, ranks each city or county relative to other cities or counties within the same group.

Police/sheriff and public works department databases


Local police/sheriff and public works departments frequently maintain databases or files of information that may be cross-referenced against collision information. Some examples are:

Citations databases. Local police or sheriff departments usually collect information on citations.

Traffic complaints databases. Local public works departments may collect information regarding traffic complaints received.

Traffic control device inventories. Local public works departments may collect information regarding the locations of traffic control devices, including traffic signals and signs.

Geographic Information Systems (GIS). Local public works departments may have GISs that include the above databases, as well as other information, such as bike lane locations, census tract information, etc. that can facilitate spatial querying. MTC also maintains a regional GIS.

Public health databases


Hospitalization databases (OSHPD and local). Local hospitals collect records on hospitalizations within their systems. The Statewide Office of Planning and Development (OSHPD) cleans and standardizes data from local hospitals and then feeds it back to county health departments in the form of a local database.

Direct downloads of aggregate patient data, called pivot profiles, are available online, but a more complete patient-level dataset is for sale. Patient discharge pivot profiles were developed using the patient discharge data file aggregated at the hospital level. The profiles display the number and percent of discharges by the various data elements available in the public file.

Some county health departments do maintain a local OSHPD database that contains information about causes of hospitalization, whether the hospitalization was fatal or non-fatal (use non-fatal only if comparing to death data), and the patient's age, gender, race/ethnicity and city/place of residence. For example, San Francisco General Hospital, the local Level I Trauma Center, maintains electronic databases for both emergency department visits and hospital stays. Injured persons are given an external cause of injury code (E-code) for the known cause of injury. The E-coded data can distinguish between motor vehicle- pedestrian or motor vehicle-bicycle collisions. Hospital data provides injury severity assessments, and may include long-term injury outcomes and disability status for each patient.

Emergency Department Data. A database of emergency room visits is under development by the State of California Department of Health Services. Collection of Emergency Department (ED) and Ambulatory Surgery (AS) data records is scheduled to begin with voluntary reporting of October 1 - December 31, 2004 encounters. The voluntary reporting period is for testing purposes only. May 15, 2005 is the due date for the first mandatory reporting period of January 1 - March 31, 2005 encounters. The data collection includes EDs that provide standby, basic, or comprehensive services.

Death databases. Local jurisdictions collect records on deaths within their jurisdictions. The California Department of Health Services cleans and standardizes the data and then feeds it back to county health departments in the form of a local database. Most county health departments do maintain a local death database that contains information about cause of death and the decedent's age, gender, race/ethnicity and city/place of residence.

Epidemiology and Prevention for Injury Control (EPIC). California Department of Health Services EPIC Unit uses hospital and death data to create an annual by-county profile of hospitalizations and deaths from injuries of all kinds, whether from drowning, playgrounds, or traffic-related causes. There is also an online query system that you can use to easily look-up county-level information about cause of death/hospitalization and the decedent/patient's age, gender, and race/ethnicity. This query system does not include the sub-county geographic information that can be very useful for more focused local planning.

California Health Interview Survey (CHIS). The California Health Interview Survey contains information about health risk behaviors such as how often teens wear a seat belt, how often teens have ridden in a car with a driver who has had alcohol, how often teens have handled guns without adult supervision, and how many adults have firearms/guns in the home. There is an online query system that makes it easy to access the data, though interpretation of local statistics (whether this is a good estimate) and comparisons between groups can remain tricky.

Behavioral Risk Factor Surveillance System (BRFSS). Online reports contain national, adult-level statistics similar to those found in the CHIS.

Youth Risk Behavior Surveillance System (YRBSS). Online reports contain national statistics about youth risk behaviors similar to those found in the CHIS.

Other Sources of Data


Other sources of data that can be cross-referenced against collision data include other government organizations (such as the Pedestrian and Bicycle Information Center: www.walkinginfo.org and www.bicyclinginfo.org), non-government organizations (NGOs such as the AAA Foundation for Traffic Safety), the general public, and the CA Department of Motor Vehicles (DMV).