Espinosa called to the stand Darrell Clardy, a toxicologist with his own company, Analytical & Forensic Toxicology Inc. of Brea. Clardy previously was a criminologist for the Orange County crime lab.
Espinosa pointed out when Reed was first interviewed by authorities, he said Mostrong drank a few sips of beer from a cup. He testified in court that he saw Mostrong drink beer from a "beer bong."
Defense witness Christina Ruiz testified Monday she saw Reed throw up from drinking too much and Reed had told her he was "wasted."
Espinosa asked Clardy if Reed could have been confused because of his level of intoxication.
Clardy responded if Reed was intoxicated, he could have been confused in his recall of events.
Espinosa presented Clardy with a hypothetical situation used by Deputy District Attorney Wayne Robinson when he had a toxicologist testify whether Mostrong was under the influence of alcohol.
Espinosa asked Clardy if a 6-foot, 175-pound young man drank five 10-ounce beers from 10:15 p.m. to 11:30 p.m. and 15 to 17 minutes later had an accident, could it be determined that person was under the influence.
Clardy responded, "No, I would have to make a lot of assumptions. It would have to be an educated guess."
Espinosa asked about the blood-alcohol level of a person who only had a couple sips of beer or two 10-ounce beers. Clardy said the blood-alcohol level would not be significant, maybe .01.
Espinosa asked if a person would be affected if he had one or two "hits" of a marijuana joint. Clardy said it would not have much effect on the system, stating, "If you just took a hit, you are not going to have any significant exposure."
Espinosa asked Clardy if he had seen the toxicology reports on the level of marijuana in Mostrong's system.
Clardy said the THC level, the active element of marijuana, in Mostrong's body indicated he had used marijuana "zero to four hours" before his blood was drawn.
Like the prosecution's toxicologist, Clardy had no answer as to whether Mostrong had any marijuana in his system at the time of the accident.
Espinosa said if Mostrong had marijuana in his system that had been used four hours before his blood was drawn, that would be consistent with statements he made to his attorney when he turned himself in to the California Highway Patrol.
Espinosa has said Mostrong told his then attorney he did have marijuana in his system, but it was not related to the crash.
Under cross-examination by Robinson, Clardy said in his opinion on average people are impaired by alcohol when their blood-alcohol level reaches .09. He said the level of when intoxication occurs can vary.
Clardy said while the law states a person is under the influence when his blood-alcohol level reaches .08, law is based on public policy and not science.
He said science shows most people would be impaired in driving at .08 to .10 and an .08 blood-alcohol level would be a low range.
Robinson said a study by the American Medical Journal states people could be impaired with a .05 blood-alcohol level. Clardy again said the scientific opinion sets the range at .08 to .10.
On the issue of mixing alcohol and marijuana, Robinson asked Clardy whether he could base an opinion on the effect of mixing the two based on studies he conducted because his studies dealt solely with alcohol.
On the topic of Reed, Robinson asked if an individual was so drunk he threw up and two hours later that person was stopped by an officer, whether an officer would be able to tell if the person was under the influence.
Clardy acknowledged the officer would be able to tell the person had been drinking.
Espinosa objected, stating Reed was not stopped by an officer.
Robinson said, "But he was, sir."
Espinosa asked Clardy if a person had thrown up, then was involved in an accident and ran two to four miles back to a party, if would have a sobering effect on a person. Clardy said it would.
Testimony will continue at 9:30 a.m. Friday.
Staff Writer Darren Simon can be reached at 337-4082.