HARRISBURG, Pa. (CBS) –– State highway crews will be adding more “tow-plows” to their fleet of winter weather vehicles this season.

The Pennsylvania Department of Transportation (PennDOT) says it will deploy the double-lane plows on highways in Montgomery County this year, and the turnpike will use them along the entire main line in the Philadelphia region as well.

The 30 foot-long tow-plows have already been used on an experimental basis. But this winter, Penndot will have eight of them in regular use in Montgomery, Allegheny, and several other counties, while the turnpike will have four.

What is a tow-plow?  PennDOT secretary Barry Schoch says it is essentially a plow truck pulling a second plow behind it.  Once in the passing lane, the second plow can then swing out to the right, enabling two lanes to be plowed at once.

And with the tow-plows in operation, Schoch says, it’s even more important for drivers to be cautious.

“Drivers should be aware of… when they see one of our plows moving over with the trailer behind it, you have to recognize that we are going to be pulling that into the right lane, so you don’t want to make a pass of a snow plow on the right side,” he warned.

The tow-plows essentially allow one truck to do the work of two.  Schoch says that will make more trucks available to plow secondary roads more quickly.

Reported by KYW Harrisburg bureau chief Tony Romeo