LARAMIE - Securing a DUI conviction in a jury trial in Wyoming is not easy, some prosecutors say.

They say it can be difficult to prove that a defendant had a blood-alcohol concentration of .08 or above at the time he was driving.

Portable breath tests are not admissible at a trial to establish blood-alcohol concentration, and Wyoming's "implied consent" law is the exclusive means by which evidence of alcohol concentration can be admitted at trial, said Steve Weichman, Teton County attorney.

If a person refuses to take a test under the law, prosecutors often have scant evidence to convince a jury beyond a reasonable doubt that the person was impaired, said Keith Gingery, a deputy county and prosecuting attorney in Teton County.

Weichman also said blood-alcohol evidence is frequently suppressed at trial based on minor technicalities that must be followed under state law. He said that can result in acquittals.

In order to introduce blood-alcohol evidence, prosecutors must follow the state Department of Health's rules and regulations under the implied consent statute.

"There is one way to get alcohol concentration evidence admitted in a DUI trial. That's when you do everything perfectly," Weichman said. "There are 1,000 ways for it not to be admitted. You make one little mistake…"

And even if someone arrested for a DUI agrees to take a test at the police station, 30 minutes or more could have elapsed since he was stopped by law enforcement. Lorrie Pozarik, facilitator for the Governor's Council on Impaired Driving, said a blood-alcohol test "could easily be done an hour and a half after a person was driving."

That can be problematic for prosecutors, because a toxicologist can only estimate a defendant's blood-alcohol concentration at the time of driving, Pozarik said, raising potential doubts in the minds of a jury.

And if a defendant had been stopped by police after recently leaving a bar or party, defense attorneys have a tendency to argue that the client consumed a lot of alcohol in a short period of time and was actually under the legal limit at the time he was driving, said Gene Rugotzke, a retired forensic toxicologist for the Department of Health who supervised alcohol testing.

Rugotzke, who has testified as an expert in hundreds of trials, said there was a bill in the Legislature that would have made it illegal to have a .08 blood-alcohol level within two hours of a DUI stop. Wyoming has such a law on the books, but it governs watercraft - not motor vehicles.

"That would be a guilty per se [conviction] unless you could prove you drank after the stop," Rugotzke said.

But the DUI bill died in the last legislative session.

"I don't think people took the time to try to figure the bill out," said Gingery, a state representative from Teton County, when asked why the legislation died. "That's why I think we have to stop the Band-Aid effect and come up with a comprehensive DUI bill."

"I think legislators are tired of all these little bills coming forward. Every session there is two or three," Gingery said. "What's so wrong with our DUI laws that every year there is two or three bills to make it better?"

Gingery advocates working on comprehensive DUI legislation in 2008 through collaboration with prosecutors in Wyoming. He said he hopes to introduce sweeping legislation in 2009.

'Probably sufficient'

Mark Garrison, a former state public defender for more than eight years in Park and Big Horn counties and a current panel attorney for the federal defender's office in Cheyenne, said comprehensive DUI legislation is not warranted.

"I think the DUI laws are probably sufficient at this juncture," Garrison said. "They lowered blood-alcohol content to .08, and I think certainly the penalties that are increasing over time are probably a deterrent enough."

Responding to comments that it is difficult to convict someone arrested for DUI without blood-alcohol evidence, Garrison said prosecutors have plenty of other evidence they can introduce at trial, including evidence of field sobriety maneuvers, erratic driving or even an automobile accident.

"I've seen lots of people convicted under the statute without BACs. Absolutely," Garrison said. "And many people simply walk and plead guilty before they even consult with an attorney."

Under state law, a person who has a .08 blood-alcohol level or above is guilty of a DUI because it is a "per se" violation, said Kerri Johnson, attorney supervisor in the Casper public defender's office. The presumption of guilt can be rebutted by the defense, but Johnson said the only possible defense she perceives is that the machine was not working properly.

Johnson said more of her clients arrested for DUI refuse to test than actually test under the implied consent law. But that does not mean most of her defendants go to trial.

"There's other evidence that the state has against them in order to get a conviction," she said, such as the behavior the defendant was exhibiting when he was pulled over by law enforcement.

Johnson said the specific requirements that must be satisfied in order to admit blood-alcohol evidence are legitimate, such as the requirements that blood is preserved and the breath machine is calibrated properly.

"There are error rates in the mechanical testing of some of this stuff," she said.

Finally, Johnson noted that a person can be convicted of DUI even if he blows under a .08. Prosecutors, she said, must show the defendants were consuming alcohol "to a degree that rendered them incapable of safely driving."

But Weichman questions the wisdom of giving people arrested for DUI the option of refusing to take an alcohol test - even though such a refusal results in a driver's license suspension.

"We've created rights that were not in the Constitution," the longtime prosecutor said. "We've created rights that allow the impaired driver to say, 'Bite a rock. I'm not taking a stinking test.'"