Caterpillar snow plow

I have never seen one of these before! I was driving to pick up Maddie and this big semi was in front of me, then it started to slide sideways on the road! That's what it looked like but then on closer inspection..... it pulled a caterpillar move and slid the back half of it over to the second lane. The front part of the truck also had a shovel, so between the front and back, it was shovelling both lanes at once! When it came to the over pass, it pulled back together to form a straight line again!!! Not to mention the fact that it was lit up and blinking like a circus exhibit!! It was the coolest thing ever! ( Now that I know it wasn't sliding off the road with me behind it! )