Believe it or not, converting some of the lanes on a congested freeway to toll lanes should benefit everyone, even the people who choose to never use the tolled lanes.
The reason has to do with the curious mechanics of traffic congestion... When roads are severely congested, you get a paradoxical situation: the more cars you jam in at one end, the fewer come out the other end.
By pricing to keep traffic speeds at 45 m.p.h. or a bit higher, the toll lanes will work with maximum efficiency. They’ll move a lot more cars through than they did when they were congested. ... So the toll lanes will actually ease the burden on the free lanes, hence the benefit even to those who never choose to pay. ...
The early projects show that motorists initially have doubts, but they become enthusiastic converts when they see and use the facilities. According to the last survey, over 70 percent of SR 91 express-lane users — and even over half of the nonusers — approve of the use of variable tolls.
--Eric A. Morris, Freakonomics blog, on why congestion tolls lift all boats