backseat vs back seat

Some examples from the web:

• They were ejected from the gun into the backseat.
• I climbed into the broken backseat...
• Matty's usual bone-us operandi was more like the backseat of his truck.
• But she's got new headlights and a roomy backseat.
• I got an a-plus in backseat.
• I can't reconfigure this backseat.
• Not that I mind the backseat.
• You'll get used to the backseat.
• Ident found this stuff under the backseat of the SUV.
• (Inhales) And the backseat did see some action.
• I'm the partner of the man in your backseat.
• Throw the key on the backseat.
• Throw the key on the backseat.
• It looks like they're moving something from the backseat.
• The backseat is empty, Mr. Hanna.
• In '69, Zodiac killed the cabdriver from the backseat.
• I will enter the compound in a compartment built into the backseat of our SUV.
• Listen, backseat birther, Shirley's on her third kid.
• Dude, there's a chainsaw in my backseat.
• My backseat looked like a water bottle graveyard.

Some examples from the web:

• Just something on the back seat.
• And Trudy keeps apologizing in the back seat.
• He must have been hiding in the back seat.
• A boy was sleeping under a blanket in the back seat.
• Put that blanket on the back seat.
• All my youth and passion... spent in that back seat.
• Put the briefcase on the back seat.
• And in the back seat of her flying car, no less.
• My phone is in the back seat.
• Her husband felt 'a strange noise from the back seat.
• Man and woman in back seat.
• You can be president of the back seat.
• He liked you on the back seat of his car.
• I'm scrubbing his blood out of the back seat.
• I like the back seat anyway.
• The mom said their car was stolen with a three-month-old in the back seat.
• In the back seat there's a cradle.
• Boarding pass down the back seat from June 2007.
• Uncle... You should get comfortable in the back seat.
• I just need to clean the back seat.