This is a good question. There are many technologies the Romans used to help them in governing such a vast empire. Let me name a few of the most important.
First, the Romans created roads. This might seem like a small thing, but in the ancient world, there were no roads. So, with the Roman roads, the Romans were able to travel so much faster, which was essential for communication, military operations, and trade.
Second, the Romans build bridges. This enabled the Romans to cross rivers when they needed to. This would help once again in communication and trade. Some of their bridges still exist today. For example, the city of Trier in Germany still uses a Roman bridge.
Third, the Romans also build aqueducts to bring water from far distances. For this reason, they were able to build cities that could be sustained. This was essential for all cities.