A serious crash involving two semi-trucks and two passenger vehicles occurred Wednesday afternoon on westbound I-70 near milepost 209 in Summit County, Colorado.
According to the Colorado State Patrol, the crash began when a westbound Freightliner semi-truck allegedly lost its brakes while descending the mountain pass. The truck reportedly struck another Freightliner in the right lane, causing both trucks to veer off the left side of the highway. One of the semis rolled onto its side in the median. The trailer from the first truck may have then hit a Toyota Rav-4 traveling eastbound before coming to a stop against a Toyota Tacoma. Five people were injured in the crash, including one passenger who suffered life-threatening injuries. The driver of the semi-truck that lost its brakes was cited for careless driving causing bodily injury.
When a commercial vehicle loses control in mountainous terrain, one of the most pressing questions is whether the truck’s braking system was functioning properly and whether the driver took appropriate precautions while navigating steep grades.
Was the Braking System in Proper Working Condition?
According to reports, the semi-truck lost its brakes shortly before the crash. That raises critical questions about the mechanical condition of the vehicle. Investigators will likely inspect the braking system for signs of wear, failure, or overheating—common risks when descending steep mountain passes. If the brakes failed due to mechanical defects or poor maintenance, there may be grounds to examine the role of the trucking company or repair provider in ensuring the truck was roadworthy.
Did the Driver Use Proper Mountain Driving Techniques?
Truck drivers traveling through high-altitude passes are expected to follow specific safety protocols, including gear selection, speed management, and use of designated runaway truck ramps. Even if the brakes eventually failed, investigators will want to determine whether the driver was using proper downhill techniques to reduce strain on the braking system. In my experience, crashes in mountain corridors often result from a combination of mechanical strain and human error, rather than one factor alone.
What Evidence Should Be Collected?
To understand the cause of the crash, investigators will likely review data from the truck’s Engine Control Module (ECM), which can show speed, brake usage, and throttle activity in the moments leading up to the collision. Physical evidence from the scene, including tire marks, resting positions, and vehicle damage, will help reconstruct how the sequence of impacts occurred. Eyewitness accounts and dashcam footage may also help clarify the driver's actions.
Why a Thorough Investigation Is Essential
With five people injured and multiple commercial vehicles involved, it’s vital to understand exactly what went wrong. When a truck loses its brakes on a steep downgrade, the consequences can be serious. In my view, determining whether this was a result of mechanical failure, driver error, or a combination of both is essential to providing answers for those affected and identifying where accountability lies.