The segment of I-405 near my home is being worked on (at great cost) so that a diamond lane can be added. Why?
"Carpooling good!" is a pretty good representation of the tone and depth and extent of the underlying analysis.
Carpooling is also unpopular and down by 16%, between the 1990 and 2000 census. As origins and destinations become ever more dispersed, the 11.2% carpooling level of 2000 will fall even further -- no matter how many diamond lanes are built.
Any one can play the game. Here is my contribution: "pricing good."
But here is more: during the Monday-Thursday 6am-9am peak only 35% of the trips are worktrips without a nonwork trip attached. Add the worktrips that are "chained" to an errand and the total rises to 45%. That means that there are a lot of trips (at least 55%) that are candidates for being priced to the off-peak (2001 NHTS is the source).
The idea is old. The numbers that make it compelling continue to pile up.