You can use the merge mileage feature to combine multiple trips into one trip.
To merge your trips from the mobile app, click on the orange speed tag button in the bottom right corner of the mileage tab. From there, use the checkboxes to select the trips that you wish to combine.
Once you have selected the necessary trips, you can click the blue arrow icon on the right to merge them into a single trip. NOTE: Merging your trips cannot be undone.
You can also merge your trips from the web app. Simply check the trips you wish to merge, then click the Merge symbol next to the trash icon: