Commuters around San Francisco on Wednesday morning should take extra caution as about 14,000 students and 84 schools are participating in international Walk and Roll to School Day.

Elsewhere, a purple minivan posed a traffic hazard on northbound U.S. Highway 101 just north of San Francisco International Airport at 6:57 a.m.

A large garbage bag blocked two lanes of traffic on northbound Interstate 280 near westbound Interstate 380 at 7:45 a.m.

The Powell Cable Car line was down at 6:17 a.m., with shuttle buses supplementing service.

Muni lines 8X-Bayshore Express, 14-Mission, 38-Geary and 49-Mission/Van Ness had longer than usual wait times as of 6:03 a.m.

An accident on southbound Highway 101 before Divisadero Street blocked at least one lane of traffic and caused delays at 8:29 a.m.

A bale of hay obstructed a lane of southbound I-280 just north of the Crystal Springs Road offramp at 8:22 a.m.