Yes those old Raleighs are great aren't they Aaron

Despite being interested in any kind of HPV developments and recumbents in general I still continue to ride my upright ladies roadster bicycles and retro-Edwardian tricycle. Why? - because as Aaron has pointed out you can just plain see better when riding around town. Being able to see if a parked car is occupied and if it is what the driver is doing can pre-warn you of a possible danger that someone is about to try and occupy the same space on the road as yourself. In such cases a quick ring of my bicycle's Lucas 'King of the Road' bell, or in the case of my tricycle a honk of the old fashioned bulb horn quickly alerts the driver that I'm there. If I was riding a recumbent I would more than likely end up with tyre marks across my chest instead.
As for the folk who run into school buses and not see them, - there are always going to be those drivers who shouldn't even be allowed outside on their own let alone be in charge of a motor car (sigh).

As somebody who does a lot of miles on a tricycle I must comment that their big failing is not being able to easily see any load you might be carrying. I owned a motorcycle and sidecar for some years and I must say they are a far more social form of transport if you're carrying a passenger. When my children were small they rode in the sidecar and it was great to be able to see them and what they were up to. (Actually most of they time they were too wide-eyed thrilled to be out with me on my motorcycle to be doing anything naughty). For carrying loads a sidecar is entirely practical and the extra width does make motorists behave themselves and treat you as another vehicle on the road. If you know what you're doing with riding a sidecar outfit a brake on the sidecar wheel isn't necessary, but if you intend to carry heavy or bulky loads it would be smart to have one. As for holding up traffic (shrugs), car drivers hold up traffic everyday and do far dafter things with their cars than I've ever seen any bicyclist do.