Definition of knight of the road in US English:

knight of the road

phrase

informal
  • A man who frequents the roads, for example, a traveling salesman, a vagrant, or (formerly) a highwayman.

    • ‘It began with the hauliers, those mild-mannered knights of the road who would no more dream of driving aggressively than of cancelling their subscription to New Internationalist magazine.’
    • ‘However, the true attitude of these knights of the road was explained by one cabbie last week.’