Don't you think that without proper roads a place will and can be cut off from the centre? and if the centre wants to remain so it needs to keep all potential opposition under check... so roads...

It was very important for the roman army to be able to move very quickly so the romans built the were so durable that it was transfered to the roman city requitments

In todays modern warfare you have RAPID DEPLOYMENT FORCES that can swiftly move into a foreign counrty within 24 hours with the use of air space. Rome had the best roads of that
time. The Greeks could not even construct a road the way the Roman engineers did. When
Jerusalem was besieged in 70 A.D., the Tenth Legion had to move like lightning to get to the rebellion. They were stationed in Syria near Damascus and to move 5 to 10 thousand men with full gear, siege equipment, as well as proviosions, then you need a proper road that will withstand wear and tear continually and have no obstructions. The Legion got to
Jerusalem at full march within a days time with time to construct a camp for themselves with fortifications. The roads also helped Rome become very cosmopolitan in trade within the empire and beyond the empire. Caravans from the east appreciated the Roman way of making roads as they were able move about with safety.