many state bike maps quantify the shoulder widths and traffic volumes to give cyclists the info to make route choices.

most state highways that have been designated as a bicycle route will have improved shoulders. some states widen the shoulders for bicycle traffic whenever a major road project is being done.

comments about riding on shoulders? on touring bike you are often moving at about 12 mph; a shoulder that is like the ones pictured in most of the pictures about could be smartly used by a cyclotourist.