Carpooling works! but it is just one variable in the commute equation. Take my current route[1] in Southern CA where I just happen to have a co-worker live close to me. We drive together in her car for about 30 miles to work which starts with 20 minutes driving congested surface streets just to get on the freeway. We then need to transverse multiple lanes and freeways to get in the carpool lane which is also congested. About an hour later of stop and go traffic, we arrive at work. Due to different work and personal schedules, we may not leave work at the same time so she will leave with her car and I will take a lyft back home. That costs me $40 to $60 one-way and still involves waiting for the driver. Of course it doesn't help the freeways are under construction[2] but when completed, I'm hopeful things will improve.
[1] https://www.mapquest.com/directions/from/us/ca/90804/to/us/c...
[2] https://octa.net/Projects-and-Programs/Under-Construction/I-...