With gasoline rapidly approaching $4/gallon in the United States, there is a renewed interest in carpooling. The Internet has provided us with new options for finding others with whom to carpool compared to those available during the gas crunches of the seventies. This is clear from the dozens – if not hundreds – of carpool sites on the Internet.

Some of those websites are only intended for commuters in a given metropolitan area. Others are intended for the entire U.S. Still others offer their services to anyone in the world. Many of the sites are not user-friendly, requiring would-be carpoolers to wade through long lists of other users, trying to figure out which users have similar schedules and have homes and workplaces close to those of the would-be carpoolers.

One of the newest websites devoted to carpooling is RideshareOptimizer.com, a free site created to allow users to easily find their optimal carpool partners. A user enters his origin and destination addresses, travel times in each direction, whether the trip is a daily commute or a single trip, and whether the user is looking for a ride or to provide a ride. The site then provides a list of potential carpool partners ordered by how far the drivers would have to go out of his or her way to pick up a rider, or vice versa.

While RideshareOptimizer.com helps users find a particular partner for carpooling, MyCasualCarpool.com, another free site, helps users use existing parking lots that are largely empty during the week (e.g., church parking lots – only with permission of the owners of the lots, of course) as park and ride lots for their daily commutes to areas with high concentrations of workers such as office parks, downtown areas, and large industrial facilities. Rather than having set carpool partners, commuters who want rides wait at the lots to be picked up by commuters offering rides.

The inspiration for MyCasualCarpool.com is a rideshare method called "slugging" by commuters in cities such as Washington, D.C. and Houston. Slugging is the practice of drivers who want to use the High Occupancy Vehicle (HOV) lanes picking up riders in designated parking lots to reach the required vehicle occupancy levels to use the HOV lanes. The driver gets to work faster and the "slug" gets a free ride. MyCasualCarpool.com allows users to propose a park and ride lot for commuters going to a particular place at a particular time, and find out how many other users are interested in such a lot.

RideshareOptimizer.com and MyCasualCarpool.com offer commuters (in the United States only) wanting to carpool new options for finding partners. Both sites welcome comments and suggestions from users and prospective users on ways to improve the sites.