Why does California not have a statewide toll road like NYS, Indiana, New Jersey, Florida and others?
The California legislature commissioned a highway financing study in 1946 as part of the
policy development that led to the Collier-Burns Act of 1947. The study's authors looked at the interurban toll roads that were then being developed in the Eastern states and specifically rejected that method of funding new road capacity because most auto travel in California was within cities, meaning urban freeways were seen as the more pressing need. Later on, in 1951, the Division of Highways (Caltrans' predecessor agency) studied a Los Angeles-San Francisco toll road, and judged it infeasible because US 99 and US 101 would have siphoned off too much traffic.
A better question is why so many eastern states have toll roads instead of paying for their freeways with gas taxes. Most of the money the tolls collect goes to pay the toll takers, not to pay for road construction or maintenance. Collecting gas taxes is very efficient.
The story varies from state to state, but common themes included a desire to avoid raising fuel taxes just to cater to interurban traffic and studies showing that turnpike corridors served very high percentages of out-of-state traffic. (We see similar dynamics today in Florida relying on turnpikes to keep the gas tax lower than it would otherwise be, and Arizona and Wyoming trying to toll I-15 and I-80 respectively.)
As a general rule, economists consider turnpikes a second-best approach because tolls claw back a part of the consumer's surplus arising from the improvement. A common theme in the highway finance literature of the late 1940's and the 1950's is amazement at motorists' willingness to pay what were then fantastic sums to use toll roads.
I can't speak for all toll agencies, but I would expect that most if not all of the traditional public-authority turnpikes publish annual reports that include financial statements. I work to the rule of thumb that toll collection and related overheads are about 30% of tolls collected, but the actual numbers and the way they are reported vary from agency to agency. For example, in the fiscal year ended June 30, 2018, the Kansas Turnpike Authority reported spending $7.8 million to collect $118 million in tolls, or 6.7%. The question is what expenses are reported under other headings that would vanish if toll collection stopped overnight.
It's certainly true that collection expenses associated with fuel taxes are quite low--about 1%.