Question

How did the Roman transportation system keep the empire strong

Answer 1

And you had a message to send for someone, the person taking it wouldn't be as lost as when they didn't have roads.

Explanation:

Answer 2

The network of roads made communication faster and more reliable. Leaders in Rome could have a good idea about what was going on in the provinces. Also, troops could be dispatched to areas that need reinforcement. And just living in a region that had Roman roads where a pathway was before was a constant reminder of who is in charge.