Cuba has around 37,800 miles of roads. Of that number, close to 20,000 miles are unpaved. That said, some downtown streets may have been paved 40 years ago and not touched since. So, what maybe a paved route, could easily feel and look unpaved.
7 of 8 toll free expressways are connected to Havana, the capital of Cuba. These roadways are called “Autopistas.” The maximum speed limit on the Autopistas is 100 km/h or 62 mph. To answer your likely question, yes – the roads are heavily patrolled by police which are part of the National Revolutionary Police Force under the administration of the Cuban Ministry of the Interior.
In some countries bribing an officer that pulls you over may seem like a good idea to avoid jail time or fines. In Cuba, don't even think about such an idea. Being a police officer in Cuba is considered to be a top honor, unlike some island countries. I spoke to one Cuban resident about such a bribe and he raised his finger while saying, “No-No.” He then placed his hands behind his back as if he were wearing handcuffs. He said, “They take you to jail.”