If you have access to public transportation, consider using it. Take those pens and pads with you. You will be amazed at how much writing you can accomplish if you leave the driving to someone else.
Within one week, I filled half a steno pad with writing. I can write very small and cramped when I need to in order to make the most use of a notebook. The pages I had written equated to 50 typewritten 8 ½ x 11 pages. Those 50 typewritten pages were then equivalent to 80 pages in a 5 x 8 inch format. It brought the total page count of my novel very close to 300 pages. That was just in one week of writing during my commute and lunch breaks.