Legends abound that the Mongolian empire was almost free from crime and violence. How true was this? The Mongolians used genocide to obliterate resistance to their rule, and there are no crimes if everyone is dead, but once rule was established, was it safer to live under it, and if so, why? The areas the Mongolians ruled over were huge and contained many sparsely populated steppes. Policing these steppes would have been impossible, so banditry seems likely, even if bandits were killed on sight if caught. Many states at the time had death for many crimes, but, looking from a European perspective, were much rougher and more dangerous than their modern counterparts due to lack of street lighting or proper police forces and widespread corruption and poverty, despite regular use of the gallows.
This does fit in a bit with Frontier and Borderlands, because it is these areas I am particularly looking at for how rule of law would be kept.
Certainly some have been sceptical about the Pax Mongolica as a concept Franke dismissed it in the 90s as 'one of those brilliant simplifications that can serve as chapter titles for world history books' and Morgan summed up his view of it by quoting the line in Tacitus 'They make desolation and call it peace.'
That said one should not discount the idea too lightly. The Mongols likely did succeed in suppressing banditry and the like, to a large extent as they often recruited the nomadic groups that would have raided merchant groups in a nice example of poacher turned gamekeeper. Furthermore they developed an impressive network of roads and waystations known as the yam which placed rest stops at regular intervals (about every 25-30 miles usually) which offered supplies and the like to travelers. Thus Mongol presence was assured all along the trade routes encompassed by their empire. Finally, one might note that should bandits persist the Mongols were well suited to rooting them out as they were also a highly mobile and effective fighting force and used to the conditions of the steppe. Rashi al-Din famously wrote ""For fear of his yasa and punishment his followers were so well disciplined that during his reign no traveller, so long as he was near his army, had need of guard or patrol on any stretch of road ; and, as is said by way of hyperbole, a woman with a golden vessel on her head might walk alone without fear or dread."
However, we should not discount the issues of official abuse which could be just as bad as banditry if not worse. The yam served also to provide free supplies and fresh horses for Mongol officials and messengers to allow quick communications, Rashis al-Din estimated a messenger could travel roughly 200 miles a day using this system. The issue was that Mongol officials could demand whatever supplies they deemed necessary from the waystations and the local communities were supposed to provide the requisite resources, the potential for grotesque exploitation is clear. This was made even worse by how merchants would often purchase official Mongol rank and then use it not only to travel free but positively make a profit by extorting local residents. While Mongke would reform the system to combat this the fact we see further reforms of it by Rashid al-Din in the Ilkhanate, again due to corruption, suggests the issue was far from completely resolved.
Bibliography:
The Mongols by David Morgan
The Mongol Empire in World History by Timothy May
'Sino-Western Contacts Under the Mongol Empire' by Herbert Franke, in Journal of the Hong Kong Branch of the Royal Asiatic Society