Overview of TIM Program
The Virginia Department of Transportation (VDOT) operates five regional transportation operations centers (TOCs) which are located in Fairfax (Northern), Richmond (Central), Hampton Roads (Eastern), Salem (Southwest), and Staunton (Northwest), as illustrated in Figure 1.[1,2] Each of the TOCs operates 24 hours a day, 7 days a week. Traffic incident information is available to VDOT’s TOCs from a variety of intelligent transportation systems (ITS) devices, including roadway sensors and closed-circuit television (CCTV) cameras.
Figure 1. VDOT Operations Regions
VDOT’s Operations Program, which handles the traffic incident management (TIM) activities throughout the state, is focused on maximizing system reliability and maintaining system access. VDOT also operates a Safety Service Patrol (SSP) program with 50 patrol routes throughout the state, covering over 500 miles of interstate highway.
Each VDOT region has its own personality which has driven the establishment of local memorandums of understanding (MOUs) and relationships with respect to TIM. Over the past few years, VDOT has been working on statewide expansion and standardization of its TIM performance measurement program, and outreach has been important in achieving a change. Through this outreach, central staff has made an effort to foster an attitude amongst regions that they are all connected within the state and to promote the idea that the collection and reporting of TIM performance measures goes beyond just the local areas and eventually needs to be rolled up to the statewide level.
Data Collection and Management
Since August 2008, VDOT has been collecting TIM data and storing that data in a database known as VaTrafffic. The data are then extracted from the database into analytical software for analysis and performance reporting. There are two primary sources of data that feed the VaTraffic database: data received and directly entered by VDOT’s regional TOC and data from law enforcement computer aided dispatch (CAD) systems, either from the Virginia State Police (VSP) or any of a number of local law enforcement agencies. TOC operators enter into the system as much information and details about the incident that is available to them. This information can be derived from viewing the incident on the CCTV cameras, via direct communication from SSP personnel on the scene, and local VDOT employees deployed to the scene for traffic control and incident management purposes.
VDOT also receives information from the VSP, which is filtered to provide only data on incidents occurring on roadways (no criminal information). When a VSP officer on the scene of an incident enters information about the incident into a mobile data terminal (e.g., electronic tablet, laptop) and/or calls the information into police dispatch, the information is automatically shared with VDOT’s regional TOC, and the information appears on the TOC operator’s control screen. The TOC operator then enters the information into the ATMS, thereby, combining TOC and VSP data. This data sharing began as a pilot project in one region to determine if it would improve incident response and coordination efforts between the agencies. After the success of the pilot project, data sharing was expanded to include all regional TOCs and VSP divisions. In addition, incident data from 15 local/county law enforcement CAD systems is shared with VDOT’s TOCs via the local/regional public safety answering points (PSAPs).
Some additional law enforcement information is collected via local/regional PSAPs, which exchange data with the advanced traffic management system (ATMS) software at each of VDOT’s regional TOCs.
Using the information gathered via the TOCs, the VSP CAD system, and VDOT personnel at the scene, VDOT is able to capture data on approximately 92 percent of the incidents that occur on the interstate highways statewide, the only exceptions being a few rural areas without many ITS devices. With the addition of data from the local/regional PSAP integrations, VDOT is able to capture data for about a quarter of the incidents on primary and arterial routes statewide, which has increased its awareness and knowledge of TIM performance outside of its primary TOC coverage areas.
VDOT captures a wide range of incident data, most of which are input as data elements in the VaTraffic database. These data elements include, but are not limited to the following:
- Incident location and type
- Roadway name and direction of travel
- Incident start time, time all lanes cleared, time scene cleared, and time event cleared
- Number of vehicles involved
- Total number of lanes
- Closures by lane
- If the incident occurred in a work zone
- Number of injuries and fatalities
- Hazmat vehicle
- Hazmat or cargo spill
- Spilled material
- Number of miles traffic is delayed
- Degree to which traffic is delayed
- Traffic impact severity
- Agencies on scene
- If state employee, property, or vehicle was involved in the incident
While VDOT’s focus has been on reporting performance measures related to incidents on interstate highways, some limited incident information is captured from primary routes (e.g., state highways) and arterial streets. In other cases, local police may call VDOT and/or VSP for assistance for incidents occurring on primary routes. When VDOT and/or VSP personnel are at the scene of the incident, they can report incident and traffic information for these incidents.
Beginning in the fall of 2015, all law enforcement agencies in Virginia began collecting the data elements for all three national TIM performance measures via the statewide crash report. Using the Traffic Records Electronic Data System (TREDS), a crash reporting software system, the crash reports are sent to the Virginia Department of Motor Vehicles (DMV). The Virginia DMV requires that all reported secondary crashes be on the same route as the traffic queue. The crash can be in either direction, but it cannot be on a secondary route or within a detour, which differs from VSP and VDOT’s definition of secondary crashes. VDOT has access to the data and shares a monthly report with the VSP, including average incident duration.
Performance Analysis and Reporting
VDOT uses the data collected to analyze TIM performance statewide, regionally, and by district/jurisdiction. VDOT considers TIM performance differently and separately for metropolitan areas versus rural areas. VDOT also looks at TIM performance by corridor (e.g., I-95, I-81), as well as separately by direction of travel. VDOT uses the TIM performance information for a wide range of strategic and tactical decisions.
VDOT analyzes and can report on a wide variety of TIM performance measures, including, but not limited to the following:
- Total number of incidents
- Number of incidents and number of incidents by location, type, time of day, and district
- Number of incidents by priority (minor, major, high profile) (auto-generated by the VaTraffic database based on information entered by user)
- Total number of SSP responses and SSP responses by incident type and roadway
- Number of lane closures
- Number of incidents involving tractor-trailer trucks
- Crash hot spots by incident type
- Incident duration when SSP responded
- Average SSP response time
- Average time from arrival on scene to clearance
- Average incident clearance time
- Percentage of incidents cleared by time category (<30 min, 30-60 min, 60-90 min, >90 min)
- Percentage of incidents >30 min
- Percentage of incidents >60 min
- Percentage of incidents >120 min
- Top 3 crashes with longest duration
VDOT has a web-based performance dashboard that presents a variety of performance data, including incident durations. Figure 2 is a screenshot of the incident duration page of the dashboard. While this page presents the aggregate analysis of incident duration of all incidents statewide over the past three months, the data can be filtered to show a more disaggregate analysis by district, incident severity, incident type, and for various time frames. At the bottom of the page, the user can choose to view the incident details, including individual ICT, or to display trends in average clearance times over the past few months.
Figure 2. VDOT’s Incident Duration Dashboard
Using this information, VDOT also produces weekly and quarterly performance reports on regional traffic incident management. Weekly reports are typically a few pages, while quarterly reports contain significantly more information and detail. One interesting graph found in the Fourth Quarter 2012 Hampton Roads TOC Performance Measures Report shows the cumulative distribution of incident clearance (Figure 3). This graph allows analysts to determine the percentage of total incidents cleared within various times – in this case, within 10 minutes, 30 minutes, and 90 minutes. Another graph from the same quarterly report (Figure 4) shows trends in the Safety Service Patrol (SSP) average response and clearance times and includes VDOT’s clearance time goal as a comparison to the actual clearance times.
Figure 3. Fourth Quarter Incident Clearance Extracted from VDOT’s Hampton Roads TOC Fourth Quarter 2012 Performance Measures Report
Figure 4. Average SSP Incident Clearance Trends Extracted from VDOT’s Hampton Roads TOC Fourth Quarter 2012 Performance Measures Report
Benefits of TIM Performance Measurement
VDOT’s regional operations director and district administrators meet regularly to use the TIM performance measure data to determine performance targets, compare with historical data, and work on definitions. The VDOT central office used the data during a process with regional and district stakeholders to determine the best measures to “tell the story” of the incident management process at the regional/district level for the Chief Engineer’s Report.
VDOT has also used performance information to optimize the way resources are deployed. For example, VDOT determined that there were a number of incidents with longer durations occurring in a rural area at the tail end of one of the SSP routes. As a result, VDOT adjusted the SSP route to obtain more coverage in this area on a regular basis, as opposed to having to pull resources from farther locations to cover these incidents.
 Dean Gustafson, Virginia’s Statewide TOC and ATMS Contract presentation, http://www.itscalifornia.org/Content/AnnualMeetings/2013/PRESENTATIONS/Tue%20Tech%20Session%205%20-%202013%20ITSCA%20VDOT%20Statewide%20TOC%20Gustafson_1.pdf.
 Virginia DOT, http://dashboard.virginiadot.org/Pages/Performance/IncidentDuration.aspx, accessed April 2015.
 Virginia DOT, Fourth Quarter 2012 Performance Measures Report – Hampton Roads Transportation Operations Center, http://www.virginiadot.org/travel/resources/hr_toc_reports/Public_HRTOC_2012_Fourth_Quarter_Report.pdf.