• Rotate the map so your path goes from left to right – that helps match up events in the graphs with their location on the map. The screen shot to the right shows the bridge and intersection that caused the spikes in IRI.
  • Get the start and end markers close to where you want them and then zoom in on the map and change to the satellite view to place them precisely. 
  • If you don’t have a network or cell connection, you can still review the results. You can have a detailed map without a network connection if you use the “Save offline map” feature in Google Maps.

Reviewing Results

  • Start RoadBump while your vehicle is at rest
  • Come to a full stop before ending the recording
  • Set a minimum speed so you don’t have to start or stop RoadBump while driving
  • Record at least a few seconds before and after the path you are measuring – you can easily set the start and end markers and save the smaller path later
  • Record long paths in 1 run and later save smaller sections as individual recordings
  • Best results are around 40 to 60 mph
  • Calculations are done based on testing on tracks with known at speeds between 30 and 60 mph. The estimated IRI results from speeds outside this range are projected from the test data.
  • Use cruise control where practical
  • Accelerate and brake smoothly
  • Drive the same path multiple times, focus on consistent lane positioning
  • Recordings over 1 hour in length are more difficult to manipulate. 


  • Flat spot on a non-slip pad on the dashboard
  • Non-slip pad on center console
  • Windshield mount (the steadier the better)
  • Floor (keep from sliding)
  • Cup holder (keep from moving)
  • Seat (keep from bouncing)
  • Thigh (really!)
  • Hand (last resort)

Device Placement - from Best to Worst

  • Put your device in Airplane mode to avoid time differences between cell towers, interruptions and to save battery life
  • GPS must be on
  • Confirm minimum speed setting is what you want
  • Confirm Vehicle / Device setting is what you want
  • Check battery status - heavy draw on the battery

Device Configuration

Tips for Usage