2.5 Selection of Data Types
Not all data types will be needed for every operational study. Some data types are needed for planning stage studies, while other data types are necessary for the Preliminary Schematics or Final/Approved Schematics and Design stages of projects. provides guidance on which data types may be necessary versus optional for the different project development stages. Required (R) data types are needed to conduct the analysis. Project specific (PS) data types may be recommended, depending on the specifics of the project. Coordinate with the TxDOT project manager regarding the necessary and optional data to be collected for each project.
Data Type | Suggested Method of Collection | Resources | Analysis Type | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Safety | Alternatives | Segments | Intersection | Interchange | Roundabout | Alt Intersection or Interchange | Microsimulation (Microscopic) | Multimodal | TIA | |||
Roadway Geometry and Configuration | Aerial imagery, as-builts, and field verification, if needed | TxDOT’s Open Data Portal, Google Maps, Bing Aerials, Nearmap, asbuilts, and other online resources | R | R | R | R | R | R | R | R | R | R |
Traffic Operational Data | Aerial imagery, as-builts, online databases, GIS, and field verification, if needed | Google Maps, Google Street view, Bing Aerials, Nearmap, asbuilts, and other online resources | R | R | R | R | R | R | R | R | R | R |
Turning Movement Counts (TMC) | Collected on a typical weekday (Tue, Wed, Thu) 2 consecutive days A minimum of 2-hour period, which includes the peak hour 15-minute increments | Traffic counting firms, MPO database, and previous studies | PS | PS | PS | R | R | R | R | R | PS | R |
Segment Traffic Counts | Collected on a typical week 7 consecutive days 14 consecutive days (microsimulation) 24-hour period 15-minute increments 100 days of data for FHWA approved projects | STARS II, MPO database, previous studies, big data, and historical counts for FHWA projects | PS | PS | R | PS | PS | PS | PS | R | PS | PS |
Classification Counts | Collected on a typical week 7 consecutive days 24-hour period 15-minute increments Includes FHWA Vehicle Types | STARS II, MPO database, and previous studies | PS | PS | PS | PS | PS | PS | PS | PS | PS | PS |
Oversaturated Counts | Collected on a typical weekday (Tue, Wed, Thu) 2 consecutive days A minimum of 3-hour period, will begin at a minimum 1 hour before and end at a minimum 1 hour after congestion Include shouldering affect 15-minute increments | CCTV cameras and previous studies | PS | PS | PS | PS | PS | PS | PS | PS | PS | NA |
Collected at least one intersection upstream of the congested study area | ||||||||||||
Queue Length | 5-minute arrival and departure counts Probe-based data for speeds and bottlenecks, license plate studies, and field observations Will start before any queues exist and end after queues have cleared | CCTV cameras and previous studies | PS | PS | PS | PS | PS | PS | PS | PS | PS | NA |
Probe-Based OD | Project specific | INRIX, Replica, and StreetLight | NA | PS | PS | NA | PS | NA | NA | PS | PS | PS |
Probe-Based Speed | Project specific | Coordinate with TxDOT project manager for access to INRIX platform | NA | PS | PS | NA | PS | NA | NA | PS | PS | PS |
Bluetooth | Project specific | RITIS | NA | PS | PS | NA | PS | NA | PS | PS | PS | NA |
Floating Car | At least 5 runs in each direction during the peak hour within the study limits | Mobile apps, gps data point collection instruments, and 3rd party vendors | NA | PS | PS | NA | NA | NA | NA | PS | PS | NA |
Multimodal Data | Time frame of collection will be similar to the period of analysis | Transit agency, Texas Bicycle and Pedestrian Count Exchange, and Transearch database | PS | PS | PS | PS | PS | PS | PS | PS | R | PS |
Crash | Minimum of previous 3 years of data | CRIS | R | PS | PS | PS | PS | PS | PS | NA | PS | NA |
Field Studies and Observations | In person field visits Planned development studies such as TIAs | TIAs | PS | PS | PS | PS | PS | PS | PS | R | PS | R |
R – Required, PS – Project Specific, NA – Not Applicable