The driver of the tanker truck that exploded on Interstate 95 this week was seen slumped forward in his cab shortly before his truck ran over a barrier and plunged from an overpass onto the highway, according to a source familiar with the investigation.
The account was given to police by a motorist who saw the driver, 64-year-old Jackie M. Frost of Finksburg, on Interstate 895 as he approached the overpass, the source said. It suggests a medical emergency as a likely possibility for the crash, which left four dead.
"It could indicate a medical emergency, or the driver could have dropped peanuts in his lap or spilled his coffee," the source said, offering possible explanations of why Frost was seen slumped over. "Everything's on the table."
Frost's family has told investigators that he did not suffer from any medical conditions, and the state medical examiner's office said an autopsy of Frost's body did not find conclusive evidence of a heart attack or stroke. Results from toxicology tests on blood samples taken from Frost's body have not come in, officials said.
Investigators from the National Transportation Safety Board said yesterday that they plan to begin gathering Frost's medical records in the coming days.
Today authorities will shut down part of I-895 for five hours today to reconstruct the movements of Frost's tanker.
Investigators said they hope the reconstruction will provide new clues to the cause of the accident.
Yesterday, they confirmed the identity of a third victim as Rita Ann Gall, 42, of Lansing, Mich., a long-haul trucker who traveled with her cocker spaniel, Dubba Dog. Remains of the dog helped identify Gall's body, her family said.
As the effort to identify victims nears conclusion, investigators are focusing on the cause of the crash. They obtained yesterday a videotape believed to show the tanker driver loading 8,800 gallons of premium Citgo gasoline into his 9,200-gallon tank minutes before the accident.
National Transportation Safety Board investigators, meanwhile, measured 165 feet of tire marks on the I-895 ramp leading to the point where the tanker ran over a Jersey wall and plunged onto I-95 below. The tire marks are in addition to about 50 feet of scrapes along the wall.
"We're looking at everything - the condition of the vehicle, the condition of the driver, the condition of the road," said Chief Gary W. McLhinney of the Maryland Transportation Authority Police. "Right now, nothing is carrying any more weight than anything else."
At noon today, NTSB investigators are expected to shut down the two ramps connecting I-895 to I-95 and then drive onto one of them a tanker truck the same size as the one that exploded Tuesday.
Using tire and scrape marks left at the accident scene, the NTSB will try to discern the truck's precise path. Such a reconstruction is typical in major crashes, officials said.
"The point is to match the marks to the vehicle," said NTSB spokesman Ted Lopatkiewicz.
I-95 will remain open, and Lopatkiewicz offered a reassurance to drivers using that route today: "We are not going to put the truck through its paces to see if it's going to flip over the highway. It's a static test." The tanker will be empty.
While investigators have been entering data collected from the crash site into a computer, they said they expect to get better information by taking a tanker truck onto the bridge to see how the accident could have occurred. The tanker truck that exploded fell rear-end first from the I-895 overpass onto I-95 northbound.
"The computer simulations are only as good as the information you put into them," Lopatkiewicz said. "We're not going to come to any conclusions [today]. It's more just trying to match the truck to the tracks."
A key revelation yesterday was that the tanker truck was nearly filled to capacity with gasoline. The tanker contained 8,900 gallons of fuel - the 8,800 loaded at a Citgo distribution center in South Baltimore plus 100 already in the tanker.
Witnesses told police the tanker was moving erratically on I-895 before it fell off the bridge, and explaining those movements is critical to the probe. Investigators said they believe the tire marks on the highway are evidence that the tanker's load was shifting side to side.
Police would not say if the nearly full tank has altered any of their theories on the cause of the crash. But tanker industry experts said significant load shifting is less likely with such a full tank.
"The worst thing is to be half full," said John Conley, vice president of the National Tank Truck Carriers trade group. "When you're driving, you'll feel the slosh effect. You'll see much more movement than when it's full."
Authorities have not ruled out a medical emergency as a contributing factor. Conley theorized that that was possible, given that the route was well-known to the tanker driver, who was headed to a Citgo station at the National Naval Medical Center in Bethesda.