State of Texas
Statewide Video License Plate Capture OD Study
Alliance conducted perhaps the largest and most comprehensive Statewide OD Travel Survey using Video License Plate Capture for the Texas Department of Transportation. License plate data were collected at 21 locations (including high-volume Interstate locations) simultaneously along the IH-35 corridor between Laredo and the Texas/Oklahoma border (approximately 500 miles) for over 48 continuous hours. The extended data collection period was due to the overall length of the corridor, and the potential for a trip to span multiple days.
Once the data were collected, optical character recognition (OCR) was used to transcribe a sampling of license plates by location and direction. A mail-out/mail-back survey was then sent to 150,000 unique Texas addresses. The return rate on the mail-back surveys was in excess of 13%. Trip end locations were converted to geographic information at the traffic analysis zone level associated with the survey station location and the location of the reported trip ends. All other data was aggregated and no private individual data was retained.
Finally, all observed license plates were transcribed by location, direction of travel, and time. Travel patterns were identified using license plate matching techniques to understand the origin and destination patterns of commercial and noncommercial vehicles using the roadways. The data was then used to generate a trip table reflecting travel patterns through the corridor.
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