Outer-borough folks are learning what Metro-North riders have long known: Fallen leaves can severely foul up your commute.

The MTA has posted signs on subway lines that go outside, reports the New York Times, warning riders to expect leaf-fueled delays.

Subway riders who thought they had come across every reason for train delays — station fires, flooded tracks and sick passengers — have been presented with a new one: falling leaves.

Transit officials have put up about 500 signs along three subway lines in recent weeks warning that fallen foliage, “crushed by moving trains,” has been leaving a “slippery residue” that “may affect the train’s ability to start and stop.” Riders of the B and Q lines, which have several open-air stops in Brooklyn, and the Franklin Avenue shuttle in Brooklyn, which is completely exposed, were told to “allow for additional travel time.”

New Yorkers are not taking the news well.

“Because of leaves?” one rider, Sylis Gordon, asked incredulously on Wednesday as she waited for the Q train at the Parkside Avenue station. “That’s new.” She looked around her, noticing garbage on the tracks, but said, “There aren’t that many leaves.”

For the second time in ten months, a GPS device has steered a driver onto the tracks in Bedford Hills, where his car was obliterated by an onrushing Metro-North train.

Metro-North riders were delayed around 90 minutes after last night’s incident.

California man Bo Bai was the object of nationwide ridicule in January, not because his name was Bo Bai, but because he claimed his car’s global positioning system (GPS) steered him right onto the tracks, parallel to the Saw Mill Parkway, where his Ford Focus became stuck.

Bai surely feels a lot better to hear that White Plains man Jose Silva experienced the same fate last night.

Writes the Journal News:

Silva of 11 O’Dell Ave., a freelance videographer, said in a telephone interview later that he was driving with his son and nephew to the Grand Prix New York Racing facility at 333 N. Bedford Road in Mount Kisco.

He said he got off the Saw Mill River Parkway on the right when his Magellan GPS unit told him to take another right - directions that landed him on top of the rails.

“My son was at my side and told me we’re on the railroad,” he said.

The three got out to try to move the Saturn. Another man also stopped to help, Silva said. They called police to report the incident and were told that railroad officials would notify any incoming trains to stop - but five to seven minutes later, the train struck the car.

The vehicle’s bumper became lodged underneath the front of the train - the 6:52 p.m. express from Grand Central Terminal to Southeast. The train had to be backed up to allow workers to remove the car, and inspect the train and the tracks for damage.

The Journal News says there’s a long history of traffic accidents on the Bedford Hills tracks.