Probe-based data is collected from individual vehicles, or probes, over space and time, rather than collected at a specific place and time. The most common types of probe-based data collection methods are Automatic Vehicle Location (AVL), Global Positioning System (GPS) mobile devices, and third-party cell phone app data. This data is typically collected by thirdparty companies that parse through the data, anonymize it, and convert individual probe data into performance measures such as speed, travel time, and OD. This data is then used for traffic analysis. The data can also be used to determine OD of trips and queuing.

Floating car data (FCD) is a type of probebased, timestamped, geospatial data that provides speeds and travel times. The data is collected by using an application or a GPS device that records timestamps and geospatial data while the application or device is driven through the area of interest. The driver attempts to “float” in the traffic stream, selecting a location in the traffic flow where the vehicle’s speed matches that of the surrounding vehicles to allow the probe to collect data of a typical vehicle along the facility during the analysis period. FCD is recommended to be collected on typical weekdays (Tuesday, Wednesday, Thursday) and during the peak period. A minimum of five runs in each direction per peak period are typically performed for a more representative view of existing traffic conditions, as demonstrated by

Figure 2-2

. FCD provides a sample of the existing congestion, speeds, stops, and travel times for the study area during a peak period.

TxDOT has access to probe-based data, such as INRIX, which can be used for traffic analysis. See

Section 2.3 Existing Traffic Operations Data Sources

in this chapter for more information.