I didn’t think a boat case from 1947 would change how I live. But here we are.
If you want the expanded version of how I actually put the case to work every single week, I broke that down in a separate note.
I first read United States v. Carroll Towing in my 1L Torts class, coffee going cold, snow hitting the window. The case is short.
If you want a quick historical refresher, the United States v. Carroll Towing Co. opinion is only a few paragraphs long.
The lesson hangs around.
By the way, not to be confused with the other United States v. Carroll—yes, the 1925 car-search decision—you can catch a concise first-person take on that branch of the Carroll family tree.
So what’s the big idea? A barge called the Anna C broke free in New York Harbor. The “bargee” (the person who should watch the barge) wasn’t there during work hours. A tug did some work, lines shifted, and things went bad. Judge Learned Hand wrote a simple check for care: if the burden (B) of a safety step is less than the chance of harm (P) times the size of that harm (L), then you should take the step. That equation is famously known among law students and economists as the Hand formula. If you don’t, that’s careless.
B < P × L. It looks cold. But it saves people.
And honestly, I use it far beyond class. I use it at work. I use it at home. I use it when I buy cocoa lids.
Why this case stuck with me
- It’s simple math you can do on a sticky note.
- It fits real life, not just courtrooms.
- It doesn’t yell. It asks, “Was the safety step cheap compared to the risk?”
Curious about how the formula plays out when the boss is watching and paychecks are on the line? I once **wrote up the exact way I used it on a job site**—numbers, pushback, weird glances and all.
But it’s not perfect. The numbers get fuzzy. People aren’t numbers. Still, it helps me slow down and choose the safer move, fast.
Quick recap, in plain words
- No watchman on the barge during the day.
- Lines were moved; the barge broke free and sank.
- The court said: a barge needs a watcher during work hours. Why? Because the cost of a watcher was small compared to the risk and the loss.
That’s the whole thing. Don’t skip small safety steps when the possible hurt is huge.
Want another vivid reminder that small safeguards matter? Read Neck Deep, a true story of how an overlooked detail almost drowned a city.
Real ways I’ve used it (yes, with numbers)
1) Winter walkway at a small building I manage
It was one of those slushy Boston mornings. I had two choices: salt now, or wait and see.
- Burden (B): $120 for salt and an hour of staff time.
- Chance (P): About 3% someone would slip if we waited. We track these; it’s not exact, but close.
- Loss (L): A fall can run around $60,000 with medical bills and time off.
Math: P × L = 0.03 × 60,000 = $1,800.
B is $120. B < PL. We salted. No slip that day. No drama. Just calm.
2) Fryer mats at my friend’s bakery
Grease on tile is sneaky. She said mats were “extra.” I pulled out my phone.
- B: $55 for a mat and 10 minutes to place it.
- P: Maybe 1% chance of a slip each busy Saturday.
- L: A bad fall here could be $20,000.
P × L = 0.01 × 20,000 = $200.
$55 < $200. We bought the mat. She also started a quick wipe schedule every hour. Still cheap. Still smart.
3) My own balcony rail (yep, home stuff counts)
I found two loose screws on the rail. I felt silly for even thinking about math. But I did it.
- B: $6 for screws and 30 minutes of my time.
- P: Tiny chance someone leans hard and falls—call it 0.5%.
- L: A fall from a second floor? I hate to think about it—call it $250,000.
P × L = 0.005 × 250,000 = $1,250.
$6 and half an hour beats $1,250 by a mile. I fixed it that night.
4) Boats at the marina (felt close to the case)
Last fall, we had a wind warning at a small marina account. Old ropes make me twitchy.
- B: $80 to bring in a part-time watch for one storm shift.
- P: Around 2% chance that night of boats breaking free if no one checks lines.
- L: One boat damaged is easily $50,000.
P × L = 0.02 × 50,000 = $1,000.
$80 < $1,000. We brought in the watch. He found two lines fraying and swapped them. He sent me a photo. I slept better.
5) Silly but real: hot cocoa lids at a kids’ game
Cold night. Booster tent. No lids in the box. I heard, “We don’t need them.” I took a breath.
- B: $18 for a sleeve of lids.
- P: Maybe 0.5% chance of a hot spill on a kid.
- L: ER visit and stress—say $5,000, not even counting tears.
P × L = 0.005 × 5,000 = $25.
$18 < $25. We grabbed lids. Parents were grateful. No spills.
What I love (and what I don’t)
What I love:
- It makes safety feel clear, not fuzzy.
- It works for boats, bakeries, and balconies.
- It helps me explain choices to owners and teams. No drama, just reasons.
What bugs me:
- Picking numbers is hard. You guess. You try to be fair. Still a guess.
- It can feel cold. People aren’t math. So I add a gut check: if the worst case is awful, I lean safe.
- Power matters. A big company can swallow more “B” than a tiny shop. So I scale steps and look for cheap wins first.
My quick checklist for interns (and myself)
- What could go wrong? Be concrete.
- P: How likely is it, even roughly?
- L: If it happens, how big is the hurt or cost?
- B: What does the fix cost in money, time, and fuss?
- Then ask: Is B less than P × L? If yes, do it. If close, I still lean safe if the harm is severe.
I also write P, L, and B on a sticky note. It keeps my head straight.
A small twist I’ve learned
Sometimes B is not just money. It’s also pride, habit, or a tiny bit of hassle. I name that out loud. “Five minutes now saves a nightmare later.” People get it. They don’t fight the step as much when they hear the trade.
Who should care
- Small business owners who stare at thin margins.
- Landlords and supers with winter steps and old rails.
- School folks who juggle kids, hot food, and cords on floors.
- Parents, honestly. Car seats. Window locks. Pool gates.
You don’t need perfect data. You need a calm look at risk.
Speaking of personal risk, a friend recently asked me to run the Carroll Towing math on her first online meet-up—new faces, unknown settings, and all the variables that come with it. We figured the cheapest “B” was using a platform with better verification and moderation before agreeing to coffee. If you’re in the same boat and want a rundown of the safest marketplaces for casual encounters, check out this guide to the **best Craigslist-style apps for meeting up**—it compares features, screening tools, and user tips so you can lower the odds of a sketchy experience without killing the spontaneity. And if your plans happen to center around Silicon Valley, you can also browse the Backpage Menlo Park personals board where curated local posts, verification cues, and neighborhood-specific safety tips make it easier to screen quickly and meet safely.
My verdict
United States v. Carroll Towing gets a solid 4.5 out of 5 from me. It’s clear, fast, and fair most days. Yes, it’s a bit