How To Properly Write Road In An Address . The city, state and zip code. Write the name of the organization on the second line. Using the road Roundabouts (184 to 190) THE HIGHWAY CODE from www.highwaycodeuk.co.uk Write the street address or post office (p.o.) box number on the second line. Because the post office reads destination addresses from the bottom of the envelope up, they may misconstrue a suite number or apartment number written below the second line as a street number without. Knowing how to write an address can sometimes get confusing.