All Music Guide has this to say about William Lee "Big Bill" Broonzy, the author of this blues classic:
In terms of his musical skill, the sheer size of his repertoire, the length and variety of his career and his influence on contemporaries and musicians who would follow, Big Bill Broonzy is among a select few of the most important figures in recorded blues history.
Key to the Highway is among Broonzy's best-known songs and has been covered countless times. Here's a clip from his own recording of the tune in the early 1940's. If you are looking for a good ear-training exercise, try your hand at both the bass line he is playing during the full instrumental chorus as well as the riff he plays after singing.
Audio Clip: Big Bill Broonzy playing Key to the Highway
Key To The Highway