Most riders know that eating and drinking are not allowed on BART trains or in "paid areas" of stations. Same goes for smoking.

The penalties can be stiff. Violators might have to fork up $250 or work off 48 hours of community service.

But a penalty is only a deterrence if it is enforced. And BART does not enforce all its rules equally.

Nobody cares if you sip on a water bottle while riding BART. If, however, you bite into sloppy tuna salad sandwich, or open a pungent carton of kimchee or splash a milkshake over a seat, you might get some angry stares or harsh words. But a citation is highly unlikely.

In 2016, BART users took 128.5 million rides on the system. Only 11 eating/drinking citations were issued between April and December. We don't know how many were handed out in the first three months of the year because BART did not record that data due to a computer upgrade. But extrapolating for January through March at the same rate of citations would result in an additional three or four.

Of course, only a fraction of BART's overall ridership eat or drink on trains or in prohibited areas of stations. There are no data on what percentage of the total ridership these light-rail snackers constitute.

But comparing the total number of rides to citations provides a yardstick to gauge enforcement of various rules across the BART system.

Last year, an eating or drinking citation was issued about once every 8,062,500 rides.

Asked how high a priority enforcement of the no eating/no drinking rule is for BART, agency media relations manager Jim Allison said it was necessary to look at the big picture.

"It's important to view enforcement of any infraction within the larger context of daily activities on BART and not just in isolation," Allison said in an email. "As calls come in about possible violations, BART police prioritize them on the basis of the relative threat to public safety and the resources available. I think you would find this form of 'triage' a common practice among law enforcement agencies."

Fare cheats cost BART a lot more than spilled food — up to $25 million annually — and the agency beefed up enforcement in 2016, ramping up citations and warnings for gate jumpers and other fare evaders in the second half of the year. That trend continued until late February of this year when it suddenly reversed itself, kicking off nearly five months of declines. In recent weeks, the numbers are again on the rise.

In 2016, a fare cheat was cited, warned or arrested only once for every 30,299 rides on the system. It's little wonder new BART police Chief Carlos Rojas has made curbing fare evasion a priority.

BART is retrofitting some stations with higher barriers and other physical barriers to discourage gate hopping. A video-surveillance pilot program is also planned.

What about other BART rule breakers? How often were they cited in 2016? Check out the slideshow.

More Information 6778 See More Collapse

Note "citations" includes citations, citation/arrests and warning citations. The latter is a citation that is not processed through the courts. BART officers also give verbal warnings, of course, but they are not documented.

The easiest way to get cited by BART is to not pay for parking or to park in an illegal space. Most of the 12 million cars left at BART stations in 2016 were legally parked, but of those that weren't, nearly 90,000 were ticketed. In January the fine for parking in daily spots without paying increased to $55 from last year's $35 penalty.

Drivers parking in spaces that require parking permits faced $75 fines, up from $40 last year.