Use the Profile pane to create and maintain the various profiles used in screening analysis. It contains the following columns:
End Threshold: When the system creates the series of major segments of the roadway being analyzed, the system uses the value in this field to determine what to do with the final segment in the series. If the final segment is less than the total segment length multiplied by the percentage value in this field, the final segment will be added to the preceding segment.
Note: The value in this field is entered as an integer, not a decimal value. For example, 10% is entered as 10, not 0.1.For example, say the profile specifies a five-mile length of roadway and that the length of the major segment is 0.6 miles. This means that the system will divide the roadway into eight equal segments that are 0.6 miles long, with the final segment being 0.2 miles long ([eight segments x 0.6 miles] + 0.2 miles = 5.0 miles). If the value of this field is set to 10, then the end-segment threshold is 0.5 miles (10% of 5.0 miles). Since the last segment is less than 0.5 miles, the system adds the segment to the preceding segment — which means the final segment in the series would be 0.8 miles long (seven 0.6 mile segments + one 0.8 mile segment = 5.0 miles).
On the other hand, if the value of this field is set to 3, then the end-segment threshold is 0.15 miles (3% of 5.0 miles). Since the last segment is greater than 0.15 miles, the system would not add the segment to the preceding segment — which means the final segment in the series stays 0.2 miles long (eight 0.6 mile segments + one 0.2 mile segment = 5.0 miles).
- Has Results: A check mark in this column indicates that the profile has been used in a screening analysis that generated results and hence the profile should not be deleted or edited.
- Is Proactive Profile: When the check box in this column is selected, the profile is a proactive profile. After the profile is used in a screening analysis, the system copies the analysis results for the main profile locations to the Proactive Safety Profile window.
- Length of Major Segments: The value in this field sets the length of the segments into which the system divides the section of roadway under analysis.
- Profile ID: This field shows the name of the profile, which is what is shown in the drop-down list in the Screening window.
- Screening Method: This field provides a drop-down list of the available screening methods. Currently, the following methods are available:
- Peak Searching: With this technique, the system divides the routes into segments based on the value in the Length of Major Segments field. Each segment is then further divided into "sub-segments" based on the value in the Sliding Window Length field. The system then calculates performance measures for each sub-segment along with a coefficient of variation.
- Simple Ranking: With this technique, the system divides the routes into segments based on the value in the Length of Major Segments field. The system then calculates performance measures for each segment and ranks the segments to derive an overall safety value. (Note that in this technique, the system does not further divide segments into sub-segments.)
Sliding Window: With this technique, the system moves a "window" (the size of which is set in the Sliding Window Length field) along the selected network element from the beginning milepost to the end milepost. The amount that the system moves the window in each iteration is set by the Sliding Window Step field.
Note: The length of the Sliding Window Step field should be less than or equal to the length of the Sliding Window Length field. If the length of the Sliding Window Step field is greater than the length of the Sliding Window Length field, then gaps will occur and parts of the roadway under analysis will be missed.
- Sliding Window Length: The value in this field sets the length of the sub-segments into which the system divides segments for the Peak Searching screening method. When the Sliding Window screening method is used, the value in this field sets the size of the window. (This field is not used in the Simple Ranking screening method.)
- Sliding Window Step: When the Sliding Window screening method is used, the value in this field sets the amount that the system moves the window in each iteration. (This field is not used in the other types of screening methods.)
- SQL Main Location ID: This field selects the SQL statement that determines the scope of the profile (that is, what part of the network will be analyzed during screening). The items in the drop-down list are configured in the SQL Main Location window.
- When you right-click this pane, the system displays a shortcut menu. This shortcut menu contains the common commands along with the following special command:
- Build Safety Location Profile: This command functions in the same was as the Create Profile command button. It runs the SQL statement and so prepares the selected profile for use in a screening analysis by populating the Main Profile Location and Secondary Profile Location panes with data.
