Many people notice that Pacer (or any step‑tracking app) sometimes counts steps when you’re not walking – for example when you’re driving, riding in a bus or train, or sitting on a motorbike.  This happens because step counters aren’t perfect: they use motion sensors to detect repeated movements and sometimes misinterpret vibrations and arm motions as walking.  Below is an explanation of why this happens and what you can do about it.

How Step Tracking Works

Modern phones and wearables use accelerometers (and sometimes gyroscopes or barometers) to detect movement.  These sensors measure acceleration along the X, Y and Z axes.  Tracking algorithms look for patterns in the data that match a person’s walking motion.  Because the sensors are so sensitive, they can also pick up arm movements or vibrations even when you aren’t walking:

• Accelerometers measure changes in speed on three axes.  When your arm moves or your device shakes, the sensor may record a series of movements that look like steps.
• Activity trackers try to filter out non‑walking motions, but vibrations can fool them.  A bumpy car ride or subway trip produces vibrations that look like the up‑and‑down pattern of walking.

Some trackers also use air‑pressure sensors to count floors climbed.  Rapid changes in air pressure (for example, in a lift or when the car goes up a hill) can be misinterpreted as stair climbing.

Why Transportation Creates False Steps

Vehicle vibrations

Most false steps come from vibrations.  A Google Pixel Watch support expert explains that multi‑axis accelerometers use hand movement for step tracking and will count motion when you ride on a bumpy road.  The Fitbit community similarly notes that devices should not count steps on smooth roads, but bumpy roads or stiff suspensions may cause extra steps.  Even if the device is sitting on the seat, mechanical vibrations can trick the accelerometer.

Arm movements and gestures

When you drive, your arms and hands are not completely still.  Moving your hand to shift gears, hold the steering wheel or adjust the radio can mimic the pendulum‑like motion of walking.  Pixel Watch specialists note that arm movements while driving contribute to inaccurate step counts.  The Apple Watch accuracy guide also warns that vigorous or unusual arm activity confounds step counts.

Algorithm limitations

Step‑counting algorithms are designed to filter out false positives, but they have limits.  Research on step counters shows that mechanical vibrations can register as steps and that wrist devices are especially prone to errors because wrist movements occur during activities such as gesturing or eating.  Raising the threshold for step detection can reduce false steps but may also miss some real steps.

Does It Matter?

False steps from driving usually amount to a few hundred steps over the course of a ride.  This won’t dramatically change your long‑term activity trends because the same error happens every day.  If you look at trends over weeks and months, the extra steps will not significantly affect your progress.

However, if you want to minimise false steps or correct your totals, the suggestions below can help.

Tips to Reduce False Steps

1. Know Your Step Source

Pacer can use different data sources:

• Phone sensor: counts steps directly from your smartphone’s accelerometer.  Vibrations and bumps will affect this source the most. 
• Apple Health or Google Fit: may combine data from your phone and wearables, so false steps can come from any device in the chain. 
• Wearables (Apple Watch, Fitbit, Garmin, Samsung Health): use wrist‑mounted accelerometers and are more sensitive to arm movements and vibrations.

Check which source Pacer is using and follow the appropriate suggestions.

2. Wear or Place Devices Appropriately

• Phone sensor: Place your phone securely (for example, in a bag pocket rather than loose in the cup holder) so that it doesn’t shake excessively.  Keeping the phone flat and stable reduces vibrations detected by the accelerometer. 
• Wearables: Wear the device on your non‑dominant hand.  Research and support articles note that devices on the non‑dominant wrist record fewer false steps.  Steering and shifting usually involve the dominant hand, so switching wrists can help.

3. Focus on Trends Rather Than Exact Numbers

It is impossible to avoid all false positives.  Step counters will always have some measurement error due to sensor limitations and varied human activities.  Pacer is designed to show relative changes in your daily activity.  If your step count is consistently increasing week after week, that reflects real progress even if a few rides add extra steps.

5. Keep Software Updated and Calibrate Devices

Manufacturers periodically update their algorithms to improve filtering.  Make sure your phone OS, Pacer app and any linked wearables are up to date. 

Conclusion

Pacer counts steps by analysing motion patterns from sensors.  Unfortunately, vibrations from cars, buses or trains and incidental arm movements can mimic step patterns and lead to false counts.  Research shows that mechanical vibrations and wrist movements are well‑known sources of error.  While you can’t completely eliminate these inaccuracies, you can reduce them by placing your phone securely, wearing your tracker on the non‑dominant hand.  Most importantly, focus on long‑term activity trends rather than a single day’s step count—consistency matters more than perfection.