It's more than "common courtesy" to clean off your car after it snows.
In some states, it's the law.
Here in Pennsylvania, one lawmaker says she's pushing to make the highways safer from so-called ice missiles.
"I saw something coming toward the window but I didn't know what it was," explained Stacy Crudele.
The Monroe County woman was driving down Route 33 in Northampton County Monday when a sheet of ice flew off a tractor-trailer and hit her car.
"It hit the ground first," Crudele added. "And then the front of the car, and then it slid up the hood and smashed the windshield."
Massive damage to her car, but luckily no one inside was hurt.
"When the ice accumulates to thick sheets, it eventually dislodges," said State Senator Lisa Boscola. "That's when they become icy bullets and missiles."
She championed a 2007 law that allows police to fine drivers between $200 and $1,000 if falling ice and snow cause serious bodily injury or death, like the 2005 death of Christine Lambert whose car was hit by a chunk of ice Christmas Day.
"We should prevent it from happening in the first place," shared Boscola.
She's been fighting to make the law tougher for the last seven years.
Boscola calls PA's law reactive, and would rather it be closer to New Jersey's version.
Drivers in the Garden State can be fined up to $75 just for leaving snow and ice on their vehicle.
The fine increases up to $1,000 if it results in any injury or property damage.
"All we're trying to say is whose responsibility is it when you have accumulated snow and ice on your vehicle," described Boscola. "It's the industries responsibility to make sure that that is off the roof because we are talking about highway safety."
Boscola tells us the trucking industry keeps blocking the effort.
"Saying we can't do this, our truckers are going to die because they have to climb on top of the roof to get the snow off."
It's an excuse she isn't buying anymore.
High mounted ice scrapers are already being used at several area companies, and Boscola says other technologies are out there to effectively clean the tops of trucks.
Allentown, PA 18102