Many people think recumbent riders sit so low that automobile drivers cannot see them. In fact, overall rider height on a recumbent is not significantly lower than on a road bike. In over 25,000 miles of recumbent riding I have never had the feeling that automobile drivers could not see me. Most short wheel base bents fit on all standard auto racks. The tandems and long wheel base bikes fit on racks with a tandem attachment.
Recumbent tricycles do have their niche.
Tricycles are great for anyone seeking total stability. Greenspeed makes tricycles that many two wheel enthusiasts find appealing. They are very stable in the corners, handle well at speed and climb everything this side of Everest. A Delta trike is configured with two wheels in the rear and one in the front. Conversely, Tadpole trikes are built with two wheels in front and one behind the rider.