...please keep in mind that hashes are randomized in Perl...

Yes, I do realise this but thanks for the reminder.

In this application, the order doesn't matter. The data is for highways. The array is to store the highway authority(ies) for each route. Given that the length of the highway is very small compared to the geographic jurisdiction of the authority, very very few cross a border. So the vast majority of routes only have one authority. Ordering them doesn't matter for the odd one that does cross a border.