(WBBM Newsradio) — Every morning at 6 in Chicago, nearly 300 crews spread out for daily garbage pickup. When the temperature is below zero, the Streets & Sanitation department’s so-called “Cold Start” program kicks in.

“Crews stay overnight to keep the trucks running,” Commissioner John Tulley tells WBBM’s Lisa Fielding.

“Cold Start” has been in effect since Dec. 22.

“Any vehicles that aren’t starting, they work with their fleet and facilities management people to jump any batteries, repair any hydraulics. Hydraulics really become an issue especially with our refuse vehicles. This week has been challenging,” Tulley says.

Tulley says they have about 290 garbage trucks and 27 recycling vehicles daily. So far, they’ve kept the fleet up and running, even though the duration of this current cold snap comes unusually early.

“This has been a week and a half now of doing this ‘Cold Start,’ and we’ll probably continue it for several more days,” Tulley says.

He doesn’t recall this many cold days in a row since the Polar Vortex in 2014.

“Thinking back on it, this is been a littler earlier than usual. Usually it’s end of January, mid-February when we have to deal with this.”

As far as his crews who work outside, Tulley says during the winter months, a supervisor is on hand with a warming van for their crews that are outside all morning.

“We go out even in the most cold, icy conditions. We provide cleats to our crews to avoid slipping. It’s cold so we ask our supervisors to pay close attention to their crews who need to warm up a little,” he says.

Some cities in the Chicagoland area have suspended or delayed garbage pickup due to the cold.