Read the guide: Why does my house shake at night?
How to test traffic and train vibration
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Step 1: Choose a room on the side of the house nearest the road or tracks, on the lowest floor. Lay the phone flat, screen up, on a hard floor near the outside wall.
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Step 2: Plug the phone in and set auto-lock to Never, so the screen stays on.
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Step 3: Tap "Start logging". On iPhone, tap Allow when Safari asks for Motion & Orientation access. A session runs for 1 hour by default. Pick a longer one if trains pass only a few times a day.
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Step 4: For the first 15 minutes, sit by a window and write down the time of each truck, bus or train that passes.
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Step 5: Match your notes with the events on the timeline. Now you know which vehicles cause the shaking and how strong each type is.
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Step 6: Log again at other times: morning rush hour, school bus times, and late at night when freight moves.
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Step 7: Download the CSV or PDF report after each session. It lists every event with its time, peak mm/s, Hz and duration.
What your result means
Your result lands on one of four levels. This page uses the people and buildings scale, which is based on peak velocity in millimeters per second (mm/s).
| Level | Range (peak velocity) | What to do |
|---|---|---|
| Barely noticeable | Under 0.25 mm/s under 0.010 in/s | Not logged at the default threshold. Normal for a house near a road. |
| Noticeable | 0.25 to 1.0 mm/s 0.010 to 0.039 in/s | Felt when you're still. Common near bus routes, truck routes and rail lines. Usually a nuisance, not a risk to the building. |
| Strong | 1.0 to 2.5 mm/s 0.039 to 0.098 in/s | Clearly felt, and windows or dishes may rattle. Look for a road defect near your house, since it's the most fixable cause. |
| Very strong | 2.5 mm/s or more 0.098 in/s or more | Unusually strong for traffic. Check for a pothole, sunken manhole cover or loose steel plate right outside. Report it, and keep the log to show the city or the railroad. |
Traffic vibration in a house usually comes from a few heavy vehicles, not from the steady flow of cars. A loaded truck or bus that hits a bump near your home sends a jolt into the ground. A freight train shakes it for as long as the train takes to pass. This test logs each event, so you can see which vehicles matter, how often they come, and at what time of day.
Why traffic vibration shakes some houses more than others
- The road surface. This is the biggest factor. Caltrans notes that vehicles on a smooth road are rarely, if ever, a source of vibration you can feel. Potholes, patched trenches, sunken manhole covers and settled pavement make wheels slam down and send a pulse into the ground.
- Heavy vehicles. In most cases only trucks and buses cause vibration you can feel, not cars. Speed makes it worse.
- Distance. Ground vibration fades quickly as it travels, so the first row of houses feels the most.
- Your house. Wood floors with long spans can bounce along with the ground, and upper floors often move more than the ground floor.
- The ground. Soil type changes how far vibration carries, so two houses the same distance from a road can feel it very differently.
Common causes and fixes
Trucks and buses
If most events line up with trucks or buses in your notes, walk the road near your house and look for the defect they hit. Report it to the city or your state department of transportation with your log. Caltrans says smoothing the pavement stops perceptible traffic vibration in virtually all cases. You can also ask about truck routes, lower speed limits and enforcement.
Trains
Freight trains usually shake more than passenger trains because they’re heavier. Worn rail joints, track defects and flat spots on wheels make it worse. Contact the railroad or transit agency with the dates and times of your strongest events. They can check the track near you.
Rattles inside the house
Caltrans also notes that loose windows, doors and dishes can rattle at very low vibration levels, and the noise makes the shaking seem worse than it is. Felt pads under dishes, tightened window sashes, weatherstripping and museum putty under shelf items stop most rattles.
When it’s not traffic
If events don’t match the vehicles in your notes, the source is probably somewhere else. Log overnight with the house vibration logger, and switch off your own furnace, AC and pumps one at a time to rule them out.
What this tool can’t measure
- Very faint vibration. Every phone sensor has its own noise. Tiny movements can sit below it.
- The true peak of a sharp jolt. The phone estimates peak velocity as RMS × √2. That works well for steady shaking, like a passing train, but can read low for a single bump.
- Fast vibration. Phones measure up to about 30 Hz. The PDF report and the CSV list your phone’s exact limit. Anything faster can show up as a false lower frequency.
- Which vehicle caused it. Only your notes can link an event to a truck or train.
- Sound. The phone measures movement, not noise.
- Time while paused. Nothing is logged while the screen is locked or the page is in the background.
Phone readings are a good guide, not a certified measurement.
Frequently asked questions
Can truck traffic damage my house?
It's unlikely. Caltrans notes that traffic, even heavy trucks on a highway, rarely causes vibration high enough for structural or cosmetic damage. It can still disturb sleep, rattle things and make you notice cracks that were already there.
Why do trains shake my house more than trucks?
A train is very heavy and long, so the shaking lasts for the whole pass, often a minute or more. Freight cars also carry much more weight per axle than trucks. Worn rail joints and flat spots on wheels add extra impacts.
Why does a session last 1 hour by default?
An hour usually catches enough trucks and buses to show a pattern, and the timeline stays easy to read. For a rail line with a few trains a day, pick a longer session or "Until I stop", and keep the phone plugged in.
Who do I contact about traffic vibration?
For a city street, call the city's public works or street department. For a highway, contact your state department of transportation. For trains, contact the railroad or the transit agency. A log with times and peaks helps them find the spot and the cause.
My windows rattle but the log is quiet. Why?
Windows, doors and stacked dishes can rattle at vibration levels you barely feel, and the noise makes the shaking seem worse than it is. Loud engines can rattle windows through the air too. Tightening loose sashes and adding weatherstripping often stops the rattle.
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