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Querying Highway Data


Using RTMIS, users can query highway data and map, email, or graph the results. To access the query wizard, select 'Highway' from the main page and then select 'Transportation Performance Indicators'. The query wizard will guide users through the process of querying the highway data. Currently, the application is using Pems as its highway data source.

Selecting & Maneuvering Items in Lists

Selecting Items in Lists

To select a single item, click on the item in the list.  To select more than one option from a list, depress the CTRL key while clicking on items in the list.  To select several consecutive items from the list begin by clicking the first item, then depress the SHIFT key while clicking on the last item of selection.  This action will select the first item clicked, the second item clicked, and all items in between. 

Unselecting Items in Lists

To unselect a single item, depress the CTRL key while clicking on the item.

Moving Item(s) Between Lists

To move selected items between lists click the single right arrow (">") or single left arrow ("<") button. To move all items, click the double right arrow (">>") or the double left arrow ("<<") button.

Reordering Items in the Selected List

The order of items in a selected list determines the order of the items in the results provided  to the user.  To move an item in the selected list on the right up, select the item by clicking the item and then click the up arrow ("^") button.  To move an item in the selected list on the right down, select the item by clicking the item and then click the down arrow ("v") button.

Data Elements

Element Units Description
Flow Vehicles/Hour The average flow in vehicles per hour
Occupancy Percentage The average occupancy in percent
Speed Miles The average speed
VMT Miles The total vehicle miles traveled
VHT Hours The total vehicle hours traveled
Q Miles/Hour The average measure of quality on the freeway. (VMT/VHT)
Travel Time Hours The total time to travel the expanse of the road segment in hours. (Length/Speed)
Delay Hours The total vehicle hours of delay
Samples Count The total number of samples collected for the hour period.
Valid Samples Count The total number of valid samples collected for the hour period

Summary Techniques

The list below provides the summary techniques (average, sum or count) applied to each loop detector reading element:

Average Flow
Average Occupancy
Average Speed
Total VMT (Vehicle Miles Traveled)
Total VHT (Vehicle Hours Traveled)
Average Q (Quality)
Total Travel Time
Total Delay
Number of Loop Detectors
Number of Sample Readings
Number of Valid Sample Readings

Grouping Query Results

If "Group Results" is selected, results of the PeMS query is organized by a user specified category type(s).  Query results can be grouped by loop detector, county, city, freeway and/or an interval of time (year, quarter, month, week, day and hour).  In the following example, the user elected to group results for his/her query by city and by freeway. (Illustrated in Image 1). The output produced from the user's "Group Results" selection is the summarized PeMS data categorized by city and by freeway. (Illustrated in Image 2.)

Image 1:  User's "Group Results" Selection

Image 2:  Output Produced from User's "Group Results" Selection

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Copyright 2003 Southern California Association of Governments