At a four-way stop, both drivers are certain they arrived first. Both are polite about it. Both go home and file a claim with a different company. Somewhere in the following weeks, two adjusters will turn those two accounts, a handful of photos, and a police report into a percentage. Understanding that process is more useful than rehearsing your argument, because the decision rarely hinges on who sounds more confident on the phone.
The first record is rarely the last word
Each carrier starts with its own insured's statement, the claim form, and whatever the police report contains. A report is influential but not always final; an officer who did not witness the collision is often recording what two people said at the scene. Photographs of vehicle positions, damage height and angle, debris, and the road layout frequently carry more weight than either narrative, because they do not change between tellings.
Witnesses matter most when they are independent. A passenger in one of the cars is usually treated as an interested party, while a pedestrian who happened to be waiting at the corner is not. If a nearby business had a camera, mention it early: many systems overwrite recordings quickly, and a request made three weeks later can arrive after the footage is gone.
How adjusters weigh the evidence
Adjusters compare the physical story with the verbal one. Damage concentrated on a front corner suggests a different sequence than a broad, even impact. A side-impact at an intersection raises questions about who entered first and at what speed. When the accounts conflict, the file may be split rather than won outright, with each carrier accepting a share of responsibility for its own insured.
This is also why the first estimate you give should be careful rather than complete. It is fine to say you do not know a distance or a speed. Guessing a number that the physical evidence later contradicts does more damage to your credibility than an honest gap in your memory.
Comparative negligence in plain terms
Many states assign a percentage of fault to each driver and reduce the recovery accordingly. If you are found partly responsible, the amount available to you may be reduced by that share. Some states apply a threshold beyond which recovery is barred altogether. These are state rules, and the details vary enough that advice from someone in another state is a poor guide. Ask your adjuster to explain the rule that applies to your claim in ordinary language.
A disputed fault finding also affects your deductible and, in some situations, your next renewal. If the outcome seems plainly wrong, the time to say so is while the file is open, with your photos and the report number in hand, not after the decision has been closed.
If your own carrier pays first
When liability is unsettled, using your own collision coverage is often the fastest way to get the car repaired. Your carrier pays, you cover the deductible, and the companies then sort out reimbursement between themselves through a process called subrogation. If your carrier recovers from the other side, some or all of that deductible may come back to you. Ask how that works in your policy, because it determines whether waiting for a fault decision is worth the delay.
Be careful with recorded statements given to the other driver's insurer. You generally owe cooperation to your own carrier, not a detailed narrative to the other side. Stick to what you observed, decline to speculate, and keep a copy of everything you send. A disputed claim is usually resolved on documents, not on whoever tells the story best.