Pick chapters, not a marathon
A commute is fragmented. Books with short chapters and clear scene breaks are easier to resume than dense argument or experimental prose. Mystery, adventure, and short-story collections are reliable choices.
Download before you leave
LibriVox and Internet Archive both offer downloadable files. Saving a few chapters before you leave avoids dead spots and data charges. Loyal Books links to public-domain recordings as well.
Keep a backup title
Volunteer recordings can have uneven volume or pacing. Keep a second short title ready so a bad chapter does not end the habit. The search page lets you filter by genre and source.
Do not pay for a classic you can hear free
If the book is public domain and a free recording exists, start there. A paid option is for convenience, a specific narrator, or a newer title, not because the free version is hidden.