Find carpools from/to desired destinations
There is a site called zimride.com that use to cater to the public and now monetized their site by only selling their service to companies and universities. It use to allow the public to organize carpools from and to desired destinations. For example, many people drive to/from Lake Tahoe from the San Francisco Bay Area on weekends. So you could search for rides from and to your desired destination. It was great and I used it a dozen times before they shut it down to the public. I met lots of great people, had company for long drives, shared expenses, and it helped to reduce traffic.
Some of the features:
Offer rides from/to a destination.
Search for rides from/to a destination (or along the way of an offered ride).
Map view showing rides offered.
Set the fee for passengers to pay to join.
Pay the driver up front through the site.
Give reviews to drivers and passengers.
Add pictures of yourself and your car.
There is no site today that offers this service and I miss it! It could be supported by advertising or we would be fine with carpool.com taking a reasonable percentage of the ride fees to support your site.