You may have some trips from the past that you want to combine into one continuous trip. The merge trips makes this a breeze and you can merge as many trips together as you would like.
Step 1: Make sure you are under the "All" tab. Once you have found the trips that need to be merged, tap on "Edit" on top right of screen.
Step 2: Select the trips you would like to merge (note the blue check marks for selecting the trip). After all trips have been selected tap on "Merge" in green area near bottom of screen.
Step 3: To view the trips that have been merged you can look for the link icon next to the mileage of the trip.
You can also merge your unclassified trips, learn more here
Need to unmerge your trips, learn more here