Massachusetts Appeals Court Reverses Motor Vehicle Homicide Conviction Resulting from Improper Expert Testimony

In an opinion issued last week, the Massachusetts Appeals Court overturned a defendant’s felony motor vehicle homicide conviction because a testifying state trooper offered an inappropriate expert opinion about the cause of the accident.  The case is Commonwealth v. Douglas Guinan.

In 2010, the defendant was driving his 2011 Hyundai Sonata on South Street in Pittsfield when he crossed over the center line and collided with an oncoming Ford Focus.  The passenger of the Ford was killed and the driver was seriously injured.  The road was dry and the defendant was driving the speed limit.  Multiple witnesses testified that the defendant’s car swerved to the left without notice and other witnesses testified that the defendant first swerved to the right, struck a curb, and then veered into the opposite lane of traffic.  There was one open can of beer in the defendant’s car and four unopened cans, and the responding police officer noted that the defendant smelled like alcohol.  The defendant’s blood alcohol content was measured to be .06, which is below the legal limit of .08.  The defendant also had a prescription for Vicodin and blood tests showed the presence of hydrocodone, which is contained in Vicodin, in his blood stream.  The neurologist and the surgeon who treated the defendant at the hospital both testified that he had sustained a brain injury at some point.

The defendant testified that he did not remember the accident or the events leading up to it.  He was convicted of felony motor vehicle homicide.

Following the accident, the defendant’s wife received a recall notice from Hyundai stating that 2011 Sonatas could have steering column intermediate shaft universal joint connections that were either improperly assembled or loose.  According to the recall notice, these defects “would” cause the driver to “lose the ability to steer the front wheels.”  The defendant’s wife delivered the recall notice to the police station.

At trial, a state trooper who is a specialist in accident reconstruction analysis testified on behalf of the Commonwealth.  The trooper is unquestionably an expert in automobile mechanics.  Following graduation from a vocational high school, the trooper worked as a car mechanic and tow truck driver before becoming a dispatcher for a municipal police department and finally joining the state police, where he received additional training and experience related to his duties as an accident reconstruction expert.  The trooper is not, however, an expert in computer software or computer engineering.  That was a problem in this case, as the defendant’s car was powered by a computer-assisted, motor-driven power steering mechanism as opposed to a mechanically-operated hydraulic power steering mechanism.  The trooper admitted that he did not possess any specific knowledge of how the software program in the Hyundai recall notice worked.

Despite his lack of knowledge regarding the computer software issues, the trooper testified extensively about the relationship between the car’s motorized power steering and the computer system.  He insisted that the power steering system could not “take over” the car.

The Appeals Court ruled, quite simply, that the trooper was improperly allowed to testify in a manner that exceeded the scope of his expertise.  The Court said that the trooper was qualified to offer an opinion about the mechanical integrity of the car but he was not qualified to offer an opinion about the electronic software update and the operation of the computer-assisted, motor-driven power steering system.  Because the accident’s cause was one of the two main questions in the case (along with whether the defendant was impaired by alcohol and/or drugs), the Appeals Court held that the improper expert opinion was cause for reversal of the defendant’s conviction.

Experts play an important role in all motor vehicle homicide cases.  This case illustrates danger of allowing an unqualified expert to offer an opinion in front of the jury.