Ron Filian and Jeff Higelin


Highlighting Progress Of The County of Riverside

Geographic Information System Based Accident Records System



The County of Riverside Geographic Information System Based Accident Records System (GIS-BARS) is being developed to provide more effective and efficient accident reporting capabilities to identify high accident roadway segments and intersections for traffic safety improvements. The project is funded through a grant from the State of California Office of Traffic and Safety as well as County funds. Accident data can be obtained from the State Wide Integrated Traffic Records System (SWITRS), but is not available until 3-6 months after the end of each quarter. Initial phases of project development has involved a substantial amount of communication and co-operation between the County, Cities, and Law Enforcement agencies to determine data entry and transfer options for improving accident information retrieval via GIS-BARS.

Automated data conversion routines for converting SWITRS data to ArcInfo data-files and point topology have been completed. Current development includes expansion of the existing Centerline layer to include Traffic Volumes, Pavement Management data (such as Surface Types and Number of Lanes), and the creation of a Traffic Control Device Inventory (TCDI). These layers will improve accident analysis capabilities using ArcInfo Routing, Dynamic Segmentation, Statistics and Buffering functions for over 12,000 miles of roadway. The project is scheduled to examine emerging technologies including Digital Imagery for video-log applications, and GPS systems for vehicle location and accident reconstruction applications.


The County of Riverside Geographic Information System Based Accident Records System (GIS-BARS) Office of Traffic Safety Grant Project is laying the foundation for expandable Traffic Engineering applications and models through a complex frame work necessary to accommodate a progressive traffic accident reporting and analyses system. GIS-BARS has allowed the County of Riverside Traffic Division to make the leap from CADD based systems to a GIS based operation.

The Project has hinged on inter-agency cooperation at three levels of Government and has required individual Multi-agency agreements and prototype projects. Accommodations for a variety of software, hardware and networking requirements have been taken into consideration as development has progressed.

Project development has required the review of traffic engineering computer programs on a commercial level, existing agency applications and reporting practices, cooperative multi-agency data collection and assembly efforts, and extensive ArcInfo applications development to accommodate a wide variety of accident reporting systems.

The project is scheduled to examine emerging technologies in the final project year including Digital Imagery for video-log applications, Global Positioning Satellite systems for vehicle location and accident reconstruction applications, and the preliminary development of Transportation Planning and Design models.


Franklin Sherkow, currently the Director of the County of Riverside's Transportation and Land Management Agency, joined the Transportation Department in July 1990. Mr Sherkow's previous position was with the Cleveland Metropolitan Organization. Upon arrival Mr. Sherkow noticed a lesser degree of inter-jurisdictional cooperation than he was accustomed to in Ohio. Frank knew from previous experience that increased interaction between County, City and State Law Enforcement and Transportation Agencies could only serve to benefit all concerned parties, particularly in the fields of Traffic Safety and Transportation Engineering.

Mr. Sherkow formed the County of Riverside Transportation Ways and Means Committee to serve as a forum through which law enforcement and transportation agencies in the area could work cooperatively to overcome mutual transportation related problems.

One of the first issues addressed by the Ways and Means Committee was the absence of a County-wide accident records system. The County-wide Accident Records System Sub-committee found that many of the local agencies were interested in the concept, especially with the development of the County of Riverside's Geographic Information System. Unfortunately, due to funding restrictions and manpower limitations, few agencies were able to actively participate in the development of such a project. The Sub-committee then searched for a source to fund a project as meaningful and necessary as a County-wide Accident Records System. Fortunately the State of California Office of Traffic Safety was very interested in the development of such a system, which held potential of expansion for use on a State-wide basis.

The Sub-committee returned these findings to the Ways and Means Committee, which in turn formed The County of Riverside Geographic Information System Based Accident Records System (GIS-BARS) Advisory Committee to secure OTS grant funding and oversee GIS-BARS project development throughout the grant period.

The GIS-BARS grant project officially commenced in July 1993, after more than eighteen months of negotiation and refinement of grant objectives. The Office of Traffic Safety allocated $621,410.00 to fund the three year GIS-BARS project.

GIS-BARS Objectives

The overall project objective is to develop and implement an efficient, ongoing, County-wide, GIS-based accident records system that will provide surveillance and identification of significant accident locations through the use of sophisticated display modeling and analysis tools through the integration of diverse engineering information on the GIS. The system will help to identify high accident rates for locations including intersections and roadway segments for deployment of Federal, State, County, and City resources to do the following within one year after the three-year project:

      A. To lower the County fatality frequency.
      B. To lower the County fatality rate per 100,000 population to
           that rate of the entire State, or lower.
      C. To lower the County injury frequency .
      D. To lower the County injury rate per 100,000 population to
           that rate of the entire State, or lower.

Two main objectives of the GIS-BARS grant are to install accident records and traffic volumes county-wide, and to develop state and city prototypes. Other engineering-related layers of information may also be developed under the grant. These include traffic sign inventory, pavement markings, and traffic control devices.

GIS-BARS Project Objectives - Specific

1.    To develop a cooperative working relationship with the appropriate
      agencies county-wide: all 24 of the incorporated Cities, Riverside
      County Sheriff's Department, the California Highway Patrol and

2.    To receive authorization from the Cities for the County to receive
      and share their SWITRS data.

3.    To write software applications and programs to integrate existing
      SWITRS data collected and disseminated by the California Highway
      Patrol into the existing County GIS.  To examine and prototype
      improvements to existing SWITRS data to include all accident data
      collected by local jurisdictions for inclusion into the GIS data
      base.  This phase will include the examination of methods to
      compile data at local levels in a consistent manner.

4.    To increase/improve analysis methods, modeling methods and
      reporting capabilities.

5.    To input all the necessary layers of information into a County-wide
      GIS data base for efficient accident retrieval: traffic counts,
      accidents by location, and roadway files (street network).

6.    To develop a City prototype program with a selected City within the

7.    To investigate the feasibility and benefits of installing other
      traffic and transportation-demand-management related layers of
      information into the GIS-based system: traffic control devices,
      pavement markings, pavement management, risk management, etc.

8.    To mobilize efforts toward using Global Positioning Satellite (GPS)
      hardware within the County, to speed collection of accident data on
      site.  This can be achieved by the officer using a combination of
      portable computers, video and GPS in the field to develop the
      reports and information in a form compatible with SWITRS formats and
      available for direct entry into the GIS system.

9.    To investigate and initiate other new technological forms of data
      input/output and communication to record and display accident
      related data and records including the use of; optical disk
      information (still photography), video, and other information and
      communication system links.

10.   To explore and identify other data entry options.  An example would
      be to have a system link directly from the police officer/unit
      directly to the public agencies: the Cities, the County and the

11.   To build an expandable, renewable system which will accept many
      different data input methods to provide information in a timely


In the development of a project which contends to allow for the electronic linking of the transportation engineering and law enforcement agencies of 26 cities, 4 surrounding counties and the State of California (over 60 individual offices) many considerations had to be taken into account.

Data Security

An initial obstacle which had to be overcome was the issue of data security. No public agency is, or will be, willing to expose itself to potential liability posed by the availability of sensitive data through a central records database. Accordingly, the cities and the State of California needed guarantees that if they were to release their accident data to the County of Riverside that the County would not in turn disseminate the data to third parties.

Two safeguards were used to establish these guarantees. First each agency was requested to sign a release for accident data which contains the following disclaimer: " It is understood that the accident information is for the development of the County of Riverside's Geographic Information System - Based Accident Records System (GIS-BARS) only and is not to be distributed by the County of Riverside, in any form, to any media, individuals, the public, other agencies or jurisdiction, without prior consent of the undersigned.". The second guarantee was to limit the amount of sensitive information stored by GIS-BARS. The State of California collects all data on reported accidents from accident reports filed by all jurisdictions the information is processed into the State- wide Integrated Traffic Records System (SWIRTS), and redistributed to the reporting agencies with the exclusion of such sensitive data as victim names and physical characteristics, addresses and drivers license numbers. Thus, the data-file format established as the standard for the GIS-BARS project excludes these items.

Hardware and Software Compatibility

Surveys were provided to each prospective participating agency office to accumulate data regarding existing automated accident reporting programs, use of GIS, hardware configurations and software platforms and programs. The surveys revealed a variety of custom software applications in use for reporting accident records reports. Examples range from a BASIC program written to interpret SWITRS data files, to one developing and one existing GIS accident reporting system in which the agency provides for manual data entry on site.

The ability to transfer data has developed as another issue worthy of note. A variety of networks (Internet, Lawnet, Cornet, Calnet, etc...) are currently in use by agencies within the realm of the GIS-BARS project. Some of the agencies, however, have no immediate plans to link to a Super- information highway network. These agencies will be accommodated by the GIS-BARS project through the use of telephone modems or floppy disk/tape transfer.

Multi-Jurisdictional Prototype Development

Five major prototype projects are proposed to facilitate the entire scope of accident record collection.

  1. State of California Highway Patrol (CHP) Headquarters, for SWITRS electronic data transfer to and from local agency and CHP area offices.
  2. CHP area office C*STARS electronic data transfer to GIS-BARS.
  3. City agency with police station reporting through a local area network.
  4. City agency contracting traffic enforcement through the Riverside County Sheriff Office for reporting through a network.
  5. City agency without network access to developing network interface for reporting through telephone modem.

Prototype Development Progress

Prototype Project 1 - initial meetings have been held with CHP Headquarters. The County of Riverside has offered it's services to aid in the development of programming to accommodate the importing and exporting of data through a network. Currently, SWITRS receives copies of hand written accident reports, then manually codes and physically enters the data. Due to the sheer volume of data this process takes a minimum of three months to process.

Accommodating a network data transfer routine will require software programming for the coding of data from the C*STARS accident reporting program. C*STARS software is emerging as the state-wide accident reporting standard for laptop and Mobile Display Computers. Software and Training is provided at no cost to the law enforcement agency through another OTS grant project.

Prototype Project 2 - The County of Riverside through grant funding will be providing the CHP Banning Area Office with three laptops and one desktop computer to initiate automated accident reporting at the station and to develop a link to the County of Riverside GIS-BARS Project. The computer equipment will be returned to the County of Riverside for redeployment to other agencies for continued project development when the CHP office can provide their own equipment. Delivery of the computers from the State to the Banning CHP Office is expected in 1996, but efforts to take earlier delivery are in progress.

Prototype Project 3 - The City of Murrieta is requesting a reallocation of funds designated for Aerial Photography (to develop a centerline network for a P.C. based GIS system through a similar OTS grant project) to purchase workstation equipment, software and network connection costs to the County of Riverside GIS. This prototype project will allow for accident data and geographic data transfer for the GIS-BARS project. The Murrieta Police Department is motivated to the development of Global Positioning Satellite coordination through GIS. Currently county and city accident location data is referenced on a primary street and a distance from a cross street. In the GIS environment non-standardized street name references are causing headaches for programmers trying to determine geo- points for accident locations. The County of Riverside may provide assistance with the GPS unit development project at the City of Murrieta to further develop our own C*STARS and GIS-BARS GPS interfacing.

Prototype Project 4 - Two primary cities are currently being considered for the Sheriff traffic enforcement prototype project. This project will link and standardize sheriff reporting functions county-wide.

Prototype Project 5 - No progress has been made on this project to date. Once the standards for reporting have been established by the other four prototype projects the telephone modem transfers should be easily accommodated.

SWITRS Data Conversion

Geo-coding Accident Locations

One of the initial programming challenges we faced was to develop a process for uploading SWITRS ascii files into an ArcInfo data file. Since the accident records provided by SWITRS are delivered on 3-1/2" floppy disks, we first needed to copy the files from a PC to our UNIX workstation. Next, we created an INFO data file with all the necessary items based on the format of the SWITRS accident records, and used the ADD FROM command to import the data. Finally, we began to develop the necessary geocoding processes to create point topology for each accident record. Lacking GPS or other coordinate reference to the accident location, several other items had to be considered when converting the data.

We chose an area between the cities of Riverside and Perris as a prototype area to begin testing. Our prototype area goals were to be able to geocode the accident locations in this area, query the database, and produce an accident pin map. Included in all accident records are the PRIMARY street (the street on which the accident occurred) the Secondary street (the street which the accident is referenced from) the Direction from the secondary street (ie. north, east etc...) and the Distance from the secondary street. Using our existing centerline network we developed several AMLs that reselect the Primary and Secondary streets, determine the nodes at which they intersect, and use an inverse routine to traverse each Primary road in the specified Direction and for the specified Distance from the Secondary road. The coordinates of this point are recorded and keyed to the accident record and can then be plotted.

Several issues became immediately apparent upon testing in the prototype area. First, we found grave inconsistencies in the way street names were being spelled and/or abbreviated on the accident records. This made it difficult to reselect the arcs in our existing centerline layer. ADDRESSPARSE helped somewhat and we were able to create points for about 65% of the records in our test area automatically. We then found that we could get about an 80% success rate if we were to manually clean up some of the commonly misspelled street names, but this we are trying to avoid.

Secondly, through error routines we discovered that in many other instances either the Direction or Distance are inconstant with arc topology, or the Primary and Secondary streets either intersect in more than one place or don't intersect at all. We are developing sub-routines to manage these problems, some of which must involve interactive processing to error check and clean-up obvious mistakes. A significant effort is being made by ourselves, the California Highway Patrol, and other local agencies to develop systems and procedures which will minimize these kinds of errors. The development of C*STARS as a standard data entry tool, and the introduction of GPS units in patrol cars are some examples.

Traffic Control Device Inventory

The development of a Traffic Control Device Inventory (TCDI) layer is expected to be handled in the same way as the conversion of SWITRS data. TCDI is currently being stored in INFOS file format and carries location information similar to SWITRS including cross-street location, which side of right-of-way, and distance from the intersection. Conversion of the TCDI layer has not yet begun and will probably be undertaken after we convert our centerline layer to a route system.

Pavement Management System

The County of Riverside also currently maintains a Pavement Management System (PMS) in INFOS file format which can be keyed by street name. Eventually, we do intend to convert the PMS database to ArcInfo routes but development has not yet begun. PMS data is important to conversion of traffic volume data and will be given much more consideration in the next several months.

Traffic Volume Assignment

The grant project will employ a Traffic Volume Layer to determine accident rates and perform related traffic collision analyses. One of the most aggressive goals in the development of this layer is to calculate traffic volume values for all public highways. The basic steps to be used in assigning values to roadways for which we do not have actual traffic volume counts are as follows:

  1. Assignment of actual traffic volume counts at point locations.
  2. Assignment of estimated point and road segment volumes in relation to physical count points based on similar point/segment attributes and a set of predetermined conditions which include the following:
    A. Pavement Management System (PMS) roadway classification.
    B. Number of lanes
    C. Land use category of Rural or Urban
  3. Test for confidence and revise methodology as necessary.

In order to test for confidence in the assignment process we plan to physically count the traffic volume on a sample of roadways to determine degree of confidence and any applicable adjustment factor. If the degree of confidence is at an acceptable level we will allow the system to remain in place. If the degree of confidence is unacceptable we will employ other factor schemes to develop an accurate estimation program.

Applications Development

Overall the field of traffic engineering is dependant on localized and limited historical data for the development of traffic warrant standards. The GIS-BARS project will track the use and effect of traffic device installation and removal to provide substantial data for determining the future of traffic engineering. The GIS-BARS project should eventually be capable of providing accurate and timely forecasting data for use in advanced planning.

The development of these models will refine application requirements and account for factors which currently require detailed and often multiple field reviews. The proposed improvements will provide Traffic Engineers and Law Enforcement personnel with the opportunity make more informed decisions and to provide an increased number of highway and intersection investigations. The GIS-BARS project proposes to provide accident data and analysis within 72 hours from the time the accident report leaves the initiating agency, eliminating the necessity to wait a minimum of six months from the beginning of the reporting quarter to receive data through the existing SWITRS system.

Report and Map Creation

In an on-going effort to provide Riverside County traffic engineers with critical information, applications are being developed to produce the following standardized reports and maps, most of which can be produced in INFO without the need for geocoding. This is itself a significant advancement.


Ron Filian, Engineering Technician II, County of Riverside Transportation Department. Ron has been with the County of Riverside for 9 years, working 3 years in surveying and 6 years in traffic investigations. Ron is the project coordinator for the GIS-BARS project and can be contacted for additional information at (909) 275-6807.

Jeff Higelin, Programmer Analyst II, County of Riverside, Transportation and Land Management Agency. Jeff has been with the County of Riverside for 6 years, working 1-1/2 years in surveying and 4-1/2 years in the G.I.S. section. Jeff is the programmer assigned to the GIS-BARS project and can be reached at (909) 275-2088.

Ron Filian, Engineering Technician II (Project Coordinator)
Jeff Higelin, Engineering Systems Programmer Analyst
County of Riverside, TLMA 2nd Fl.
PO Box 1090
Riverside, Ca 92502
Telephone: (909) 275-2088
Fax: (909) 275-6847