ON response below. Yes and NO They are shorter because the chest plates they are attached to are longer so if you use the plate they are made for they are fine to jump in but the TRACK bibs have larger rings than many of the jumping reins and reins stops slide through the racing bib rings.
Secondly they have a HUGE place in safety in young jumpers and young stallions that can grab at their chests or play with the standard running attachments. If you have ever seen a wreck from a young horse grabbing a standard martingale you would know they prevent a lot of shenanigans. CWD and a couple saddle company make BIBS with perfect sized rings.
“You can find them in any racing catalog. However, beware that most are quite short…way shorter than I would ever jump in. The bib martingale also can make steering difficult as it kind of prevents the rider from using an opening rein. They’re useful on the track to limit some silliness, but I can’t see much use in them for a sport horse. http://www.bigdweb.com/Leather-Forks/products/309/”