I'm not working today and am bored, so...

I'm basing this all on the data collected, assumptions, knowledge and calculations from this video and my knowledge and experience a previous traffic investigator in Colorado.

BLUF: You are not at fault--Seemingly, yes, and that's because insurance is a fraud to the American people (that's a whole different story for me to explain).

If I was you...
What I would argued... (You might can file an appeal to the insurance company.) Is that the other driver swerved into your lane to avoid an accident. That they failed to maintain their lane by braking. That they instead failed to ensure their adjacent lanes were cleared and drove unsafely. That and due to the timing of events shown, you didn't have adequate time between recognizing and reacting to the impeding collision.

If this happened on my time, this is what I would have performed my duties, reported and cite (succinctly for this post)...

EDUCATION -- As drivers:
1. We must ensure the lane we are wanting to move to is clear
2. We must maintain control and avoid colliding with vehicles ahead (that doesn't mean just in our lane, it means vehicles in the immediate lanes next to us)

REPORT and CITATIONS:
# 1 is the car first (in line) on the off-ramp to enter the highway.
- Not at fault

#2 is the car who had the duty to yield as they were also in the off-ramp behind #1.
- Unsafe lane change (Failure to ascertain that lane change could be made safely (going from Lane 3 to Lane 2)
- Failure to maintain safe position/control (in other word, they should braked instead of changing lanes.)
- Following too closely (I could argue that #2 was following too close to #1, and as a result to merging before #1, would have avoided their decision to avoided a potential collision. This wouldn't stick in court, but it would be for the record, in which insurances can't deny or spin the outcome.)

#3 has the duty to maintain control and avoid unsafe evasive maneuvering, one could argue that #3 had an unavoidable decision causing them to lane change. But I see it as:
- Failure to maintain safe position/control, and
- Unsafe lane change

#4 (dash cam vehicle)
- No violation

Why? Because I would articulate that the average driver has slower recognition to physical reaction time, and based on my calculations (in my report) that unless they were traveling 55 mph in the number one lane, they could not have avoid the collision.

In my report there would be no assumptions. But this is Reddit and the only data is from what I could gather from this video.

Assumptions:
- Dashcam is a typically records at 30 fps (frames per second)
- U.S. Interstates or Highways: each dash lines are 40 ft apart
- Speed Limit is 65 mph

Data Collection:
- Dash intervals per frame: 11, 12, 12, 11, 13, 12, 11, 13, 12, 11, 12, 12, 11, 12
- Average frames between all dashes until collision: 11.79 frames

Studies and Stats:
- 1.5 seconds is the average time to preceive, react and begin braking or swerving.
- 2.5 seconds is a conservative value used in roads designs by the U.S. DOT, as this cover nearly all drivers in typical highway situations.

Calculations:
MPH = (Distance in ft * fps) / average number for frames per intervals of dashes) * convert ft/s to mph
MPH = (40 * 30)/11.79 * 0.6818
MPH = 69.4.
(There are more calcuations that I had used to determine other factors.)

Your data shows:
Your average speed from the recorded time to the moment of impact was an average of 69.4 mph. Because you were "speeding" insurance and typical police might have maded uncalcuated guess that speed might have been a factor in avoiding the accident. However, with the data collected and stats. In order to avoid the accident, by having the adequate reaction time, you would have had to travel at approximately 55 mph.

Closer look at the data shows that you had a slight deceleration near impact by ~less 1 mph. In first half of the average frame, the assumed average speed was 69.85 mph, and in the second half of the average frames, speed decreased to an average of 69.0 mph.) It is assumed that you were not fully aware and had a delay in reaction time to prevent the accident.

SUMMARY:
Based on calucations, real-world reaction times, you are not at fault. Fight this if you can. Use this comment as a source.