(d) The handlebar ends shall be solidly plugged and
attachments thereto shall be fashioned in such a way as to
minimize danger without impairing steering. Handlebars used
for steering with ends, features, or attachments that extend
forward or upward or that provide support for other than the
rider's hands are permitted only in time trial and pursuit
events (not in Team Sprint); however, attachments that point
upward on the brakehoods of road bicycles are allowed if the
distance between them is greater than 25 cm (9.8 inches).
https://s3.amazonaws.com/USACWeb/for...k-Chapter1.pdf