Before you can monitor travel time data in the Travel Times Engine, you must configure how travel times are calculated for your traffic links.
Before you begin
What you should know
- To get an average speed, all the source and destination nodes are used.
- Traffic links can be configured to weight toward the source or destination nodes for a calculated travel time.
- Traffic link travel time can be smoothed.
Procedure
-
From the Travel Times Engine web page, hover over the
Admin menu, and select Traffic links.
The Traffic links page is displayed.
- Select your traffic link from the list.
- Hover over the Travel time settings menu and click Travel time settings ().
-
If you are using a native travel time calculation, configure the following
settings:
- Traffic link type
- Select Native.
- Use traversal listener
- If you specified a traversal listener REST API URL in the system configuration file, this checkbox is selected. The REST API is posted each time that a traversal is completed in this traffic link.
- Algorithm
- Select the algorithm to use to calculate travel times for this traffic link. For more information about algorithms, see Travel time calculation in the Travel Times Engine
- No data calculation type
- Set how the Engine calculates travel time if it is not receiving data.
-
- Historical blend or free flow
- Returns a weighted average of the historical and free flow travel times as the value.
- Not calculated
- Returns
No data
as the value. - Free flow
- Returns the free flow travel time as the value.
- Historical
- Returns the historical travel time as the value.
- Source detection processing
- Select which detection instance from the source node is used in the calculation.
- Deduct only during traversal
- If enabled, vehicles that are detected at a deduction node are only deducted from traversals if they have not already been detected at a destination node. This setting is disabled by default.
- Allow extensions after traversal
- If enabled, a traffic link with multiple destination nodes extends the traversals of vehicles that are detected at multiple destination nodes to the time of the later detection.
- Destination detection processing
- Select which detection instance from the destination node is used in the
calculation. NOTE: This should match the configuration for Source detection processing.
- Fuzzy matching
- If you are using an ALPR detector, set the number of differences in license plate characters allowed to consider a read as a match.
- Post-traversal processing delay
- Set the wait time before a traversal is included in the calculation.
- Repeat source detection tolerance
- Set the wait time before a vehicle that has traversed the source and destination nodes can traverse the source node and be considered in the calculation again.
-
If you are not using a native travel times calculation, configure the following
settings:
- Traffic link type
- Select the data provider.
- Use traversal listener
- If you specified a traversal listener REST API URL in the system configuration file, this check box is selected. The REST API is posted each time that a traversal is completed on this traffic link.
- Update frequency
- Set how often the system queries the sensor for travel time data during daylight hours, or 5am to 10pm according to the time zone of the node. Your Travel time organization is charged per query sent.
- Off-peak update frequency
- Set how often the system queries the sensor for travel time data during nighttime hours, or 10pm to 5am according to the time zone of the node. Your Travel time organization is charged per query sent.
- Click OK.
-
To configure your algorithm settings, hover over the Travel Time
Settings menu and click Algorithm settings and
configure as needed.
NOTE: You can also save and load algorithm settings to use them for other traffic links by clicking Save As... and Load.
-
On the Traffic link details page, hover over the Notification
settings menu, click Change notification settings
()
and configure the following settings:
- Tier 0
- Speed or travel time threshold for when traffic is considered free-flowing.
- Tier 1
- Speed or travel time threshold for when traffic is considered slow.
- Tier 2
- Speed or travel time threshold for when traffic is considered extremely slow.
- Threshold buffer
- Wait time for when travel times or speeds are fluctuating near a threshold. The system waits for a traffic link's travel time or speed to stay above a configured threshold before it changes the traffic link's state to a different tier.
- Slower than historical percentage
- Relative threshold for when traffic is considered slow.
- Much slower than historical percentage
- Relative threshold for when traffic is considered extremely slow.
NOTE: For historical percentage settings, the system compares current data to previous data for the same time and day of the week, based on a rolling average of the last 4 weeks. - Click OK.
-
On the Traffic link details page, hover over the
General menu and click Change general settings
() and do
the following:
- Select Archive.
- Set the Free flow travel time option to the expected travel time when there is no traffic.
- Set the Minimum travel time option to the lowest travel time to include in travel time calculations. This is used to filter out detections of vehicles traveling at below-average speeds.
-
Click OK.
The traffic link is active.
After you finish
- Create traffic routes.
- You can copy your travel time settings to other traffic links. To do this, navigate to
the Traffic link details page and:
- Hover over the Travel Time Settings menu.
- Click Apply to other traffic links.
- Select the traffic links you want to copy your configuration to and click OK.
Parent topic: Creating traffic links in the Travel Times Engine