Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Report
• The percentage of freeway center-line miles for which travel times can be obtained for
specific times-of-the-day and days-of-the-week; the accuracy of the information (actual
vs. predicted);
• The percentage of arterial center-line miles for which travel times can be obtained for
specific times-of-the-day and days-of-the-week; the accuracy of the information (actual
vs. predicted);
• The percentage of urban area roadway miles for which real-time traffic-disruption data
(such as incidents, accidents, work zone closures, weather-related slowdowns) are
available;
• The percentage of statewide rural roadway miles for which real-time traffic-disruption
data (incidents, accidents, work zone closures, weather-related slowdowns) are available;
and
• The percentage of all disruptions for which forecasts of the effects of the disruption,
based on the characteristics of the actual disruption, are available.
The private sector will likely play an important role in the dissemination of this information. It is
also likely that the private sector will be responsible for the collection of a significant portion of
the basic roadway-performance (travel time/speed) data. However, the initial collection and
preliminary dissemination of much of the disruption data (accidents, incidents, and construction
traffic) will be the responsibility of the public sector as public sector agencies will be at the
scenes of these events. For similar reasons, the public sector will need to supply the descriptive
information necessary to predict the effects of those disruptions because the magnitude of the
effects is a function of both the nature of the disruption and the response to that disruption. Only
the public sector will know the applied response and be able to supply information related to
planned work zones. Figure 3.1 presents a flow diagram showing the collection, analysis, and
dissemination of performance and disruption information.
Figure 3.1 Collection, Analysis and Dissemination of Performance and Disruption
Information
Developing Performance Measures and Setting Goals
Identifying performance measures is only the first step in setting performance goals. The second
and more challenging step involves identifying the points at which roadway performance meets
the desired goals of the transportation agencies, stakeholders, and decision makers. The act of
GOALS AND PERFORMANCE TARGETS Page 32