Expert testifies low-speed impact posed no threat to officers

The prosecution in the murder trial of Derrick Stafford focused on proving that Stafford and other officers at the scene of a fatal traffic stop were in no life-threatening danger from a vehicle being "used as a weapon," as defense attorneys have claimed occurred on the night of Nov. 3, 2015 at a dead-end street in Marksville.

State Police Sgt. Howard Johnson, an accident reconstruction expert , testified that in his opinion there was a collision between Christopher Few’s Kia Sport and co-defendant Norris Greenhouse Jr.’s Crown Victoria patrol unit that night. However, he said the minimal damage to both vehicles indicates impact at less than 5 mph.

In addition, the damage cannot definitively tell whether Greenhouse bumped into the back of Few’s vehicle or Few backed up and contacted Greenhouse’s unit.

One other unanswered question about the Greenhouse unit’s damage is why a missing piece of fiberglass from the vehicle’s hood was not found at the scene. Johnson said it should’ve been found close to the Crown Vic, but it was never recovered. That small missing piece of fiberglass leaves open the possibility that the contact between the two vehicles occurred elsewhere that night.

Johnson said the angle of the impact between the two vehicles indicates the Kia was turning left at the time of contact.

At one point during his testimony, Johnson was asked to review the body camera video from MPD Lt. Ken Parnell as the patrol units are pursuing Few, just before Few turned into the dead end at the intersectdion of Taensas and Martin Luther King.

Johnson said there is a point where Few’s reverse lights come on. Using landmarks at the site that he can see in the video, Johnson estimated the distance the vehicle backed from the point when the lights came on until they went off.

Based on his tests and analysis, Few backed up at about 8.1 mph.

The damage on the rear of Few’s Kia consisted of scuffs on the bumper.

There were two contact points on the Crown Victoria -- scuffs on the bumper and the small hole punched into the hood.

Johnson said a rear hinge on the Kia appears to have caused the damage to the hood. It was 30 inches from the ground to the hinge. The hood is 34 inches from the ground. Johnson explained that the damages can still match up if there is a “weight shift,” caused by a sudden braking. That action would cause the front of the Kia to go down and the rear to rise, were the vehicle backing.

He said the same would happen if Greenhouse were going toward the Kia, hit his brakes and then contacted the vehicle from the rear. The patrol unit’s nose would dip and the impact point could account for the difference in the actual height of the vehicles.

Johnson also noted that the “pre-tensioner” in the vehicles’ seatbelts was not activated, which occurs at impacts of 10 mph or more, but an impact at that speed might not activate the airbags. He said he has never seen a pre-tensioner activate in a collision of 5 mph or so.

On cross-examination, LaCour asked if it is true that the pre-tensioner not being activated could be due to Few not wearing a seatbelt and Greenhouse being out of the vehicle.

Johnson said the ”black box” that controls airbags and seatbelt systems in vehicles acts based on the speed and severity of impact, not on whether the seat belts are in use. In fact, the "crash data recorder" actually tells investigators if a seat belt was in use. The pre-tension mechanism of a seat belt would roll up the belt and lock it if an accident occurred and the seat belt was not in use.

On cross-examination, LaCour attempted to discredit Johnson’s tests on the time it would take the officers to exit their vehicles and arrive at the positions they were in at the time of the shooting. He pointed out that Johnson, at 54, cannot move as fast as Greenhouse or Stafford and that his tests are therefore invalid.

Johnson disagreed, saying the distances involved were so short -- 8 feet for Greenhouse from the front of his vehicle to the position at the time shots were fired and 23 feet for Stafford from his passenger side door to where he was standing when he fired his weapon -- that there would be no significant difference in time that he could cover those distances and a younger officer could.

Assistant Attorney Genereal Matthew Derbes turned LaCour’s argument around on the defense on his rebuttal opportunity.

"You're not saying you can take Norris Greenhouse Jr. in a 40-yard dash, or even a 20-yard dash, are you," Derbes asked. Johnson said that was correct.

Derbes then noted that a young, physically fit and athletic police officer such as Greenhouse "could have easily avoided that vehicle” even if it was backing up toward him, even quicker than a 54-year-old trooper could.

He noted that an average jogging speed is 10-15 mph, and a “fast walk” is about 8 mph -- the same speed Johnson’s analysis estimates the Kia would have been moving.