Fault on a rear-end crash is usually the easy part. Boulder County files get fought over the severity of the injury and over how much of it the crash actually caused.
The impact was too minor to injure anyone. Bumper systems are engineered to absorb and rebound from low-speed impacts rather than to record them, so visible damage tracks occupant injury poorly.
Same-day documentation, imaging and a treating physician opinion answer that directly. It surfaces most often in the South Boulder Road crashes, where speeds genuinely are low.
You stopped too suddenly. Under C.R.S. 13-21-111 an insurer needs to move only 50 percent of the fault to defeat the claim completely, which is why this one is pushed hard even when it is weak.
On a highway carrying local turning traffic, braking for a vehicle ahead is ordinary careful driving. Witness accounts and the scene evidence are what establish that.
The treatment went on longer than the injury justified. Where care is delivered close to home it tends to continue further into recovery, and adjusters read duration as inflation.
The answer is the treating record itself, showing what changed and when. Continuity of care is evidence of a genuine course of treatment rather than an argument against it.
The symptoms come from an earlier condition. Prior records get requested to build an alternative explanation for neck and back findings.
A treating physician who can separate a pre-existing finding from an acute post-crash change is what answers it. The distinction is medical, and it needs to be documented as such.
The other driver had no coverage. Colorado is a fault-based state, so the claim runs against the at-fault driver liability insurer, and where that driver carries minimum limits or nothing, uninsured and underinsured coverage on your own policy or an employer commercial policy may apply.
On a regional highway the striking driver often lives well outside Boulder County, which affects both the available coverage and where a suit may be filed.
Those questions are worked through in is Colorado a no-fault state and in hit by an uninsured driver in Colorado.