5. EVALUATION FINDINGS
5.1 SYSTEM PERFORMANCE
The primary system performance assessment findings are as follows:
- From interviews and observations, the system meets functional specifications.
- From observations, the CAD and TMC can link incidents. Observed incidents from the CAD terminal displayed properly in the integrated system.
- From observations and interviews, some TMC incident response procedures were improved. When an operator used the integrated system (latency was not considered an overriding problem), the time it took an operator to enter an incident from the WSP CAD system into the WSDOT CARS system is reduced. The accuracy of the information in the incident record was improved because information from the WSP CAD system was imported directly into the CARS system, thereby reducing the chance of making an error compared to the operator entering the data manually.
- Geo-location data passed with the incident reduces the chance that the incident will be placed in the wrong location.
- From observations, the integrated system reduces the reliance on manual methods for exchanging information. Incidents from the WSP CAD system are automatically brought into the WSDOT system. In regions that don't have WSP CAD terminals, the integration system reduced operator reliance on searching for information from other sources.
- From observations and interviews, integration increased the extent and reliability of information exchanges. Information is passed from the WSP CAD system directly into the WSDOT system, so conversations are only needed to clarify information.
5.2 SYSTEM IMPACT
Washington State had implemented improved operational procedures between WSDOT and WSP prior to deploying the integrated system. Benefits from sharing data were previously realized. The CAD-TMC integration provides enhancements, not new benefits.
The integrated system was deployed for only a short time before after project data was collected. Some quantitative data was obtained and analyzed, but the State has not had adequate time to use the system and develop a database that might be used to develop an empirical estimate of system impact.
Evaluation findings related to system impact are qualitative, as follows:
- From empirical data, there was very little impact on system productivity. However, there was an increase in the total number of CARS incidents in the after data set compared to the before data set. The main reason identified for this increase was the focus on incident reporting as a result of the FOT. This increase should reflect an increase in the number of incidents reported to 511 and the Web site, which represents an improved flow of information to the public.
- As mentioned under system performance, in regions that did not previously have a WSP CAD terminal, communication between WSDOT operators and WSP dispatchers could be more focused on clarifying details rather than gathering all the information needed to report and manage an incident.
- From observations, efficiency in documenting incident management improved, especially for regions that did not have WSP CAD terminals. (See the similar finding under System Performance above.)
5.3 INSTITUTIONAL CHALLENGES
In general, Washington faced fewer institutional challenges than would be expected in most States in implementing an integrated CAD-TMC system. WSDOT and WSP have a very close working relationship. However, there were some institutional challenges that the agencies involved had to overcome. The institutional challenges are described in sections 5.3.1 through 5.3.4.
5.3.1. Inclusion of Secondary Responders
WSDOT wanted to include additional response agencies in the FOT. WSDOT looked for an agency that was interested and of a size that would not burden the initial implementation with too much complexity; therefore, Skagit County EMS was selected for that reason. The challenge with Skagit County EMS was in finding benefits worth the agency's participation. Originally, WSDOT thought that incident information might help in routing emergency response vehicles. It turned out that Skagit County EMS was too small, with too focused a mission to be a qualified candidate for this FOT.
5.3.2. WSP Use of WSDOT Data
As stated is section 2, WSDOT originally intended to be able to populate event information in the WSP CAD system through a "hazard flag." The WSP system would directly show traffic conditions, event information, and construction and maintenance activities. However, the CAD application did not lend itself to ingesting the WSDOT data in the manner originally envisioned. Instead, WSP dispatchers can access WSDOT event information through a Web interface and congestion information through either a Web interface or TMC workstation software. The problem with this approach is that dispatchers have to change their normal work processes to access and view this information.
5.3.3. Geographic Boundary Differences
The WSP districts and the WSDOT regions do not share completely common areas of the State. Therefore, when the WSP-CAD data is brought into the WSDOT system, a simple filter for WSP District does not work for many of the WSDOT Regions. It is more challenging to ensure that the WSDOT Region TMC operators see all incidents that apply to their specific regions. As a result, operators need to seek out incidents in more WSP districts as a result. A technical solution, additional filtering schemes, will be able to help with this institutional challenge.
5.3.4. Rural versus Urban Needs
One difference in urban versus rural needs, timeliness of information and problems with latency, has been discussed previously. In urban areas where trips typically are shorter, more information is typically available, and dedicated traffic management staff exist, latency on the order of 4 minutes as in the Washington CAD-TMC integrated system may not be tolerable by the operators involved.
However, in rural areas, where operators have many other duties in addition to traffic management, trips tend to be longer, and less information is available from other sources, the automation provided by the integrated system is a tremendous benefit. In fact, it is possible that a greater degree of automation in those areas might be beneficial. During many hours throughout the week, there simply were not enough personnel to effectively manage the incident information and "accept" the incidents that come from the WSP CAD system. It may be appropriate to establish filtering criteria that would automatically post certain types of incidents from the WSP CAD system directly into CARS for distribution to 511 and the Web site. In general, there may be reasons to have different approaches rural and urban areas based on the organizational, traveler, and operator needs in each.
5.4 TECHNICAL CHALLENGES
Even though the Washington CAD-TMC integration project was a technical success, there were some technical challenges. The way in which the WSDOT and WSP overcame these challenges may be instructive to other agencies considering a similar project. The technical challenges are described in sections 5.4.1 through 5.4.4.
5.4.1 Latency
As described in section 4, there is a latency of nearly 4 minutes from the time the WSP dispatchers enter an incident in the CAD system to when the information is presented in the 511 system or on the Web site. This latency does not appear to be a significant issue in rural areas, but is in urban areas, especially Seattle and Tacoma. WSDOT improved the latency by using more powerful servers. If the WSP system is upgraded to use IEEE 1512 codes and messages, the latency will be further reduced because the WSDOT system will not need to translate from the WSP codes to 1512 codes. However, there will continue to be some latency because both the WSP CAD system and the CARS system report information to external systems on a fixed periodic basis rather than as new information or updates are entered. In the case of the WSP CAD system, information is transmitted every 2 minutes. This leads some WSDOT operators to enter all of the CAD information into CARS manually.
It is important for other agencies considering the implementation of an integrated system to consider latency in the design of the system. What latency is acceptable? Are there different levels of latency that are acceptable in different areas of the State? Most likely, the answers will be different for each State.
5.4.2 CAD System Upgrade Schedules
The integration required that the WSP CAD system be modified. WSP contracted directly with its respective CAD vendor to upgrade its system. WSDOT and its integrator were dependent upon the CAD vendor schedules and software releases for the implementation of the overall project. This is a situation that other States that may be considering a similar integration need to be aware of and for which appropriate plans need to be made.
5.4.3 Geo-location
As discussed in section 4, WSDOT had to translate the WSP State Plane Coordinates to latitude-longitude coordinates. This is certainly technically feasible, and agencies need to recognize that the discrepancies in translation will change as the geographic area increases. Over a larger geographic area there would be distortions as the plane coordinate system is translated to the spherical coordinates of latitude-longitude.
Agencies considering an integrated system should be aware of the various geo-referencing schemes used by the systems involved so accurate translation can be included in the schedule and budget.
5.4.4 Use of Standards
The WSP CAD system does not use IEEE 1512 codes internally. WSDOT had to develop a translator to change the CAD codes into 1512 codes. The steps that WSDOT takes in this process are:
- The WSP CAD system pushes data to a File Transfer Protocol (FTP) site.
- Data is filtered to remove any sensitive data that should not be made available publicly.
- The WSDOT system then pulls the WSP CAD data from the FTP site and converts the CAD codes into IEEE 1512 codes.
- Data is then pushed to CARS by a 1512 message and Extendable Markup Language (XML).
- Data is incorporated into CARS and can be used by WSDOT for incident management activities and for providing information to the public (511, Web site).
The system was designed to allow the translation to simply be removed if the sending system (WSP CAD) uses IEEE 1512 codes and messages.