For the second time in as many days, a San Francisco street collapsed in on itself leaving a sinkhole where there once was firm ground. Although not nearly as dramatic as Tuesday's chasm that left an Uber SUV teetering on its edge, CBS 5 reports that yesterday morning's sinkhole did manage to the disrupt both vehicular traffic and the bike lane in which it opened.

Charles Sheehan, a spokesperson with the San Francisco Public Utilities Commission, told KRON 4 that the sinkhole was first reported around 9:00 a.m., and that unlike Tuesday's Mission Street sinkhole it should be repaired quickly. As crews worked to fill the roughly 18-inch hole on Polk at Post Street, a Department of Parking and Traffic worker remained on site to both direct cyclists around the hole and to keep cars from getting too close.

The Chronicle spoke with a different San Francisco Public Utilities Commission spokeswoman, Jean Walsh, who informed the paper that while she was unsure what exactly caused the Polk Street sinkhole, she did know that it was not an old pipe as was the case with the larger sinkhole Tuesday.

Yesterday, of course, was Bike to Work Day — and the irony of a sinkhole opening up in a bike lane on a day meant to encourage and celebrate cycling was not lost on at least one passerby.

Related: [Update] Part Of Mission Street Closed Downtown By Large Sinkhole