During no refusal weekends police record the process.
Click on the video in the above media player to watch the case of a young man pulled over for driving without headlights.
Prosecutors believe over the Fourth of July the word had gotten out about this new tool.
"The good news is that there was no DWI fatality around the county on the two nights we did the No Refusal Weekend," said Harris County Assistant District Attorney Warren Diepraam.
The DA's office in Galveston County says 23 suspected drunk drivers were forced to give blood. In Harris County where the focus was on the southeast side there were 18 forced blood draws.
But the controversial method is under fire from some attorneys.
"I believe it's an unreasonable search and seizure under the Fourth Amendment because they are without a person's permission taking their very bodily fluids for what is a Class B misdemeanor," said attorney Randall Kallinen.
In the first year of the No Refusal Program in Harris County, the DA's office says of the 100 forced blood draws, just three samples were found to be below the legal limit. Those three cases were dismissed.
"The blood tests don't lie, people believe blood, juries believe blood and I'd even think defense attorneys believe blood which is why they're protesting," Diepraam said.
And while these suspects didn't like being on camera or having a needle stuck in their arm, prosecutors say it is only used as a last resort.
"It's only after they've been given every opportunity do we actually go through with a search warrant," Diepraam said.
The DA's office says the next No Refusal Weekends are scheduled for Labor Day, Halloween and Christmas. But they add at any time investigators can request search warrants for blood on any case.
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