I rear-ended someone who admitted they let their insurance lapse — do I just report it?

Report it to your insurance. Full stop. The moment she mentioned handling it privately, the clock started ticking on how this could go sideways for you. You rear-ended her — that's the narrative. If she develops a "mystery injury" two weeks from now and lawyers up, you want a paper trail that started the day of the accident, not a text chain where you agreed to keep it quiet.

One thing people don't realize: even if YOU choose not to file, she could still file a claim against you later — especially if she decides her "minor" whiplash is actually serious once she talks to someone. At that point you have no contemporaneous record, no adjuster photos, nothing. Private deals after accidents almost always benefit the person who was in the weaker position at the scene, not you.

Just want to flag the medical side of this — soft tissue injuries from low-speed rear-ends can genuinely take days to show up. I'm not saying she's planning anything shady, but adrenaline masks a lot right after a crash. That's partly why it's risky to call it "minor" and move on without documentation. If symptoms appear later, everyone's story about what happened gets murkier.

To answer your specific questions: Most states don't require you to proactively report to your insurer by law, but almost every policy has a cooperation clause that obligates you to notify them of any accident that could result in a claim. If she later sues you and your insurer finds out you knew and didn't tell them, they could potentially use that against you when it comes to coverage. Also — uninsured motorist coverage is often specifically for situations like this, but you usually have to actually file for it to kick in. Worth a call to your insurer just to understand your options before you decide anything.

I processed claims for years. The "let's keep this between us" conversation happens constantly after accidents, and the vast majority of the time the person who agreed to it ends up regretting it. Here's what I saw play out repeatedly: people shake hands at the scene, exchange numbers, and then three weeks later one party has a lawyer. At that point you're arguing over what was said in a parking lot with no witnesses. Your insurer is not going to suspend her license — that's a state DMV issue. Your job is just to report the accident honestly. What happens to her driving privileges after that is between her and the DMV.

Not legal advice, but I'll say this: the liability picture you described — rear-end collision — is pretty unfavorable for you in most jurisdictions regardless of her insurance status. That actually makes it more important to get your insurer involved early so they can manage any future claim, not less. The private settlement route only works when both parties are truly done with the matter, and you can't know that yet. If you go that route, at minimum you'd want a signed release — but even then, releases for personal injury can be complicated. Talk to a professional before agreeing to anything.

I get why you feel guilty — you seem like a genuinely decent person. But protecting yourself isn't the same as being cruel to her. She made the choice to drive without insurance every single day for six weeks. You didn't put her in that position.