UPPER EAST SIDE — Call it the crosstown crawler.
The M79 is the slowest bus in the city, traveling across 79th Street at an excruciating 3.2 mph on average around lunchtime, according to an annual report on public transit released by the Straphangers Campaign Thursday.
“The fastest lava flow they've clocked in Hawaii is 6 mph, whereas we found the M79 went at 3.2 miles,” said Gene Russianoff, the staff attorney for the Straphangers Campaign.
“My strong advice to you, if you ever find yourself in a situation where you're trying to outrun an exploding volcano, do not, do not, get on an M79 bus. It's faster to flee on foot."
Rider Bill Levkoff, a dress manufacturer on the Upper East Side, said he wasn’t surprised by the findings.
“There are long lines because it’s so slow,” said Levkoff, 61, as he waited for the bus on 79th Street and First Avenue Thursday. “To go one block takes quite a few minutes. I can walk faster than the bus moves.”
The M15 local was the city's least dependable bus, with 33 percent arriving bunched together or with major gaps in service.
“Bus riders don’t know when the bus is ever going to come,” said Paul Steely White, 44, the executive director of Transportation Alternatives. “When the bus does finally come, it’s not uncommon for there to be three buses bunched together.”
The Straphangers Campaign determined the B41 to be the slowest bus in Brooklyn, traveling at just 5.7 mph, while the Bx19 brought up the rear in The Bronx, meandering at 4.8 mph.
The slowest bus in Queens was the Q58, at 7.7 mph, while the S48/98 was the worst in Staten Island at 8.3 mph, according to the Straphangers Campaign.
"The fact that buses are slow in New York will not come as a surprise to the 3 million riders they have each day," Russianoff said. "It's a chronic problem that New Yorkers struggle with all the time."
The MTA thanked the Straphangers Campaign for its "insightful reports" and added that riders should see improvements as the number of select service lines increases.
"Plans are currently underway for the roll-out of SBS service along four other corridors, including an additional crosstown route," the agency said in a statement.
"We are also continuing to work with the New York City Department of Transportation to increase the number of bus lanes and locations where buses would have traffic signal priority."