The Virginia DOT produces weekly and quarterly performance reports on regional traffic incident management. Weekly reports typically contain a few pages, while quarterly reports contain significantly more information and detail. As with the report from FDOT, VDOT’s report provides high-level summary statistics and is highly graphical. The first two figures below show example graphics from VDOT’s Hampton Roads TOC Fourth Quarter 2012 Performance Measures Report. The first figure is a summary graphic on the performance of VDOT’s safety service patrol (SSP). This graph shows the average SSP response time, the average time from SSP arrival on the scene to incident clearance, and the average incident clearance time. The line graph illustrates the trends over a 6-month period, including the current quarter and previous quarter. This graphic is particularly effective as it clearly identifies and defines the performance measures being presented and provides a statement of the bottom line. It also provides VDOT’s target performance for a basis of comparison to the current performance.
The graph shown in the first figure below summarizes VDOT’s fourth quarter 2012 event clearance times. The graph is a cumulative distribution curve representing the clearance times of all incidents measured during the quarter. With this type of curve, one can see the percentage of total incidents cleared under any specific time, for example under 30 minutes or under 60 minutes. In this particular graphic, VDOT has called out the percentage of incidents cleared under 10 minutes, 30 minutes, and 90 minutes.
Full performance reports from VDOT can be accessed via VDOT’s website (23).
In addition to its weekly and quarterly performance reports, VDOT has a web-based performance dashboard. The figure below shows the component of the dashboard that details incident duration (or ICT) (24). The dashboard is interactive, allowing the user to examine incident duration in terms of percentage of incidents (shown as a pie chart) or number of incidents (shown as a bar chart). Incident duration is clearly defined for the user to the right of the incident duration graph. Users can also view the incident duration graphs for individual regions or statewide, for different incident severity levels (minor, major, or high profile), by incident type (vehicle or tractor trailer), and for different date ranges (year to date, last 3 months, last 13 months). The bottom graphic shows the incident clearance trends over time according to the date range selected by the user, and the details tab allows users to see the specifics of the individual incidents, including the date, district, severity and actual start and end times of each incident.