LOS ANGELES (KABC) -- A think tank has come up with a solution to Los Angeles' traffic gridlock, but it comes with a hefty price tag of $700 billion.Los Angeles drivers spent an estimated 623 million hours sitting in traffic last year, and it's only getting worse.Tuesday, the think tank Reason Foundation issued the results of a study that it says could greatly increase mobility. The $700 billion plan focuses on buses, tolls, tunnels and technology, and true to the foundation's libertarian roots, the plan won't pick your pocket."No new taxes. This can be paid for with existing revenue plus tolling," explained Baruch Feigenbaum, the author of Reason Foundation's "Mobility Plan." The plan gives Los Angeles express lanes, tolled expressways and tunnels, miles and miles of tunnels, toll lanes just for trucks, expanded bus corridors and pretty much gives us a new map of L.A."It really is a combination of using tolling to offer people a choice to improve mobility, putting in a few tunnels around Los Angeles," Feigenbaum said.The plan is heavy on bus service and does not add any more light rail. Among the 25-year mega projects, it extends the 710 Freeway with a tunnel, plus a tunnel downtown and across the valley. So how realistic is this?"We tried to make it as realistic as possible. We had some other projects. We had a seventh tunnel in there. I looked at it and I said that this one is definitely not realistic," Feigenbaum said. "So, only six tunnels."Like all new ideas, some of these may sound a little outside the lines. But freeways may have sounded outside the lines when they were first built 85 years ago.