BART is poised to spend millions of dollars to halt fare cheating, but it turns out the transit agency is largely powerless to punish gate-jumping juveniles — thanks to a new state law.

Under the law, which took effect in January, “those under 18 years of age cannot be arrested or cited for fare evasion,” acting BART Police Chief Jeffrey Jennings wrote in a training bulletin to his officers on March 16.

The law, SB882 by state Sen. Robert Hertzberg, D-Van Nuys, was directed at keeping juveniles from racking up misdemeanor arrests on their records just for jumping fare gates.

The result: BART has yet to issue a single citation to a juvenile fare jumper this year.

BART says fare evaders are costing the system up to $25 million a year. The mob of 40-plus juveniles who took over a train car at the Coliseum Station on April 22 and robbed the passengers committed a host of crimes — but it should be noted that they also all jumped the fare gates.

BART officials insist that the new state law doesn’t mean juvenile offenders are given a free pass to ride their system. Station agents and police can refuse entry to juveniles who don’t have a ticket, “and BART can eject juvenile fare evaders from the system,” said spokesman Jim Allison.

That said, Allison acknowledged that BART’s hands are largely tied when it comes to young gate-crashers.

That’s not the story in San Francisco, thanks to a special legislative exemption that took effect last year. Muni can still issue $58 “administrative citations” that leave no mark on the juvenile jumper’s record.

BART is now considering enacting a new district ordinance to allow for such administrative fines.

“What type of penalty remains to be seen,” Allison said. It could be a monetary fine or simply community service.

Not that BART has really gone after young gate-crashers in the past. Its numbers for 2015, the most recent ones available, show it issued just 172 citations to juvenile fare cheats.

Secret mission: After leading the Democratic denunciation of the Trumpcare vote, House Minority Leader Nancy Pelosi and seven of her congressional colleagues jetted off for a whirlwind tour of India, Nepal, Germany and Belgium.

She said the focus is national security, the global economy, bilateral and multilateral relations, and human rights.

In other words, it’s a junket.

Citing security concerns, Pelosi’s press office declined to say exactly where in those four far-flung countries the delegation would be touching down — or how long it would be gone.

Gas siphon: Critics of Gov. Jerry Brown’s $52 billion road repair program question whether money raised by higher gas taxes and vehicle fees could be siphoned off to fill gaps in the state’s general fund.

“In the immortal words of the former mayor of Carmel, ‘That’s not going to happen,’” said state Finance Department spokesman H.D. Palmer, quoting Clint Eastwood.

According to Palmer, the state Constitution bars tapping current gas taxes and vehicle registration fees for general-fund uses. The new fees in Brown’s program will be similarly restricted under a constitutional amendment headed for the June 2018 ballot, Palmer said.

So what’s to keep the state, which will start collecting the new fees in January, from diverting funds ahead of the June vote?

“The governor’s veto pen,” Palmer said.

Of course, all that could be moot if Assemblyman Travis Allen, R-Huntington Beach (Orange County), has his way. He has just announced a petition drive for a November 2018 ballot initiative to repeal the governor’s transportation package.

Once he gets the green light on the language from the attorney general, Allen and his allies will have 215 days to collect 365,880 signatures of registered voters. He says he’s absolutely confident he’ll get there, given the response he’s gotten out the gate.

“We already pay among the highest tax rates in the nation,” Allen tells us, “and the new gas tax will only increase what California already pays.”

San Francisco Chronicle columnists Phillip Matier and Andrew Ross appear Sundays, Mondays and Wednesdays. Matier can be seen on the KPIX TV morning and evening news. He can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call (415) 777-8815, or email matierandross@sfchronicle.com. Twitter: @matierandross