Lakewood police are beginning a lengthy and complex investigation that will require extensive forensic work and nuanced legal judgment.

The horrific truck crash on I-70 that killed four people in Lakewood, Colorado will require a multi-disciplinary investigation to determine the final cause.  The fiery crash happened on Thursday afternoon. The 28-vehicle pileup occurred when a semi-trailer slammed full speed into a group of cars that were nearly stopped in traffic on I-70 due to a separate accident further east. In addition to the fatalities, ten people went to the hospital with injuries. The 23-year old truck driver Rogel Lazaro Aguilera-Mederos sustained minor injuries and is being held on suspicion of multiple counts of vehicular homicide.

What is Vehicular Homicide?

As a former Deputy District Attorney in Jefferson County, I have prosecuted the crime of vehicular homicide. It is a class 4 felony that carries a presumptive prison range of 2 to 6 years, to a maximum of 12 years for each count. Prison is not mandatory for this class of felony. Depending on the harm, the facts, and the defendant's criminal history, a judge would have discretion to sentence a person to probation in lieu of prison.

The offense is codified at section 18-3-106 of the Colorado Revised Statutes. Colorado has two versions of vehicular homicide. One version requires proof of intoxicated driving, a second version requires proof of reckless driving.

According to initial statements by the Lakewood Police Department, it does not appear that investigators suspect the truck driver was under the influence.  Investigators are focusing instead on 18-3-106(1)(a), C.R.S. which requires proof beyond a reasonable doubt that a person “[drove] a motor vehicle in a reckless manner, and such conduct is the proximate cause of the death of another.”

Vehicular homicide is different from other types of homicide in Colorado in that it does not require proof that the driver intended to hurt or kill someone, nor does it require proof that the driver acted knowingly or willfully. This is known as a strict liability crime. The prosecution is required only to prove that the driver voluntarily operated the vehicle, drove recklessly, and the reckless driving caused the death of another person.

Where will the investigation go from here?

Investigators will almost certainly focus on a broad array of facts including witness statements, video, photographs, accident reconstruction and forensic testing. They will also look closely at the mechanical condition of the truck, including the steering, brake and suspension systems, the brake system components, vehicle dynamics, black box data recorder, and the weight and loading of the freight.

The initial facts suggest a possible brake failure while the eastbound truck was coming down from the mountains west of Denver on I-70.  Video taken by a motorist shows a tractor-trailer swerving across several lanes which may have been the result of evasive action taken by the driver after the brakes failed. Widely reported statements by the driver's brother in law, Elvis Sedeno, suggest that the truck driver believes a brake failure caused him to lose control of the tractor trailer.

In addition to reviewing video and talking with witnesses, including the driver, who is currently cooperating with police, investigators will likely focus on the tractor trailer's mechanical systems including the brake system. Forensic mechanics will attempt to study the brake components to determine whether there was in-fact a mechanical failure. If so, the investigation will focus on whether the brake components failed due to poor maintenance, improper driving technique, or catastrophic failure of the braking components due to product failure.  It is also possible some combination of the above came together in a perfect storm leading to a catastrophic brake system failure.

Driver Conduct

The driver has a CDL license and would have been required to keep a log of his driving activities including time on the road, rest breaks, and reports of any mechanical problems along the way. If the driver kept proper logs, and they survived the crash, or were electronically recorded, they may provide useful information about emerging mechanical problems.  The logs should also reveal whether the driver completed the proper vehicle inspections each day and whether he took the proper amount of rest breaks.

If there was a brake system failure, investigators will likely focus on whether the driver had training and experience in steep grade mountain driving.  I-70 in the high country is sprinkled with runaway truck ramps. Crash investigators will likely trace the path of the semi as it came down from the mountains to determine when the brakes failed and whether the driver missed opportunities to use the runaway truck ramps.

Investigators will also focus on whether the driver exercised proper low-gear driving technique when descending Colorado's steep-grade mountain highways. Warning signs along eastbound I-70 coming out of the mountains alert truck drivers that the grade remains steep well into the foothills that lead into the Denver metro area.

Black Box Recorder

The black box recorder is often referred to as an ECM or engine control module. They can be located on different places around the truck's engine depending on the make and model of the engine. ECMs don't always survive the crash, but when they do, they can provide useful information such as a hard brake report, last stop record, engine activity, diagnostics, trip activity, and engine faults.  This data may provide important insight into the speed of vehicle and braking activity immediately before the crash.

If brake failure caused the crash, will it be a valid defense?

It depends on whether the brake failure was due to operator error or mechanical failure. If the brakes had been well maintained and failed through no-fault of the driver, a brake system failure may constitute a partial or complete defense against charges of vehicular homicide. The legal analysis will look at the entire picture that led to the crash including the driver's experience and operation of the semi, the mechanical condition of the tractor-trailer, and perhaps most importantly, the decisions the driver made after the brakes failed.