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Former detective explains the many layers of major crash investigations

The attorney for the driver who has been arrested for the I-70 crash claims it was caused by mechanical failure.

DENVER — An attorney for the truck driver involved in the crash and fire on I-70 last week says there’s “good evidence” that the truck malfunctioned.

Four people were killed and several others were injured in the pileup on I-70 and the Denver West interchange that caused a fire so intense that it melted the roadway and metal off of cars. Police said the crash involved at least 28 vehicles, including 24 cars and four semis.

Lakewood police said semi-truck driver Rogel Lazaro Aguilera-Mederos, 23, of Houston, Texas, caused the crash. He has been taken into custody on four charges of vehicular homicide, police said.   

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Evidence of mechanical failure hasn’t been made public, but 9NEWS learned the truck company that driver Rogel Aguilera-Mederos works for, Castellano 03 Trucking LLC, has a history of safety issues with at least 10 violations for brake problems.

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“There's a lot of parts that could fail, unfortunately,” said Mike Stogsdill, an accident reconstructionist and former crash unit detective. “With the friction comes heat. If you get too much heat you can get melting of the pieces inside which we call glazing, which can actually cause less friction.”

He said investigators can look at several components on the truck’s brake system that might have failed. 

Drivers are also expected to inspect their trucks, including brakes, before each trip. Maintenance logs can often play an important role in the investigation, Stogsdill said. Onboard electronics can also provide crucial data.

“It can give us information such as the vehicle speed, engine speed, what kind of faults may or may not have been present at the time. That could include brakes, engine, oil,” he said.

Physical evidence from the actual crash site will play an important role, he said, but investigations work themselves back to the first sign of trouble. 

In the case of the I-70 truck crash, witness video shows the truck passing up a runaway lane while appearing to have brake problems.

“Mechanical is one aspect. And then you have the human element. There’s always a human element,” said Stogsdill. “Drivers, especially big vehicles, coming down the mountain, need to gear down so they’re using a lower gear, which means they’re going to go slower.”

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Aguilera-Mederos said his brakes failed, causing the truck to speed up to 85 mph and into stopped traffic. 

Investigators point out in the arrest affidavit that he passed up not just the runaway ramp but also signs reminding drivers of the steep grade. The affidavit doesn’t say if the driver was being negligent.

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The investigation is still ongoing. 

All of these components and more will have to come together to determine if the four counts of vehicular homicide expected to be filed against the driver on Friday are warranted.

“They’ve got a long arduous process to sift through it all, put it back together. It’s just like a puzzle. Every piece is going to be put back together so that they can try to get the picture at the end,” said Stogsdill.

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