The road network of Bulgaria has been a subject of many dynamic improvements during the last years. However the conditions in some parts of the country are still very unsatisfactory.
The international U5 motorway links Bulgaria with Europe and with Asia Minor. It forks at Sofia, and its southern branch proceeds to Greece as U5N, while the second (U5S) leads to Turkey. Motorways link Sofia with Varna ("Hemus"), and Sofia with Plovdiv and Bourgas ("Trakia").
The Country road network consist of first-class to third-class roads. Most of the roads are first and second class. Problems may occur at roads under reconstruction and local stretches of poor condition due to lorries and agricultural vehicles using the same roads.
Pedestrian movement on the first-class roads and motorways is forbidden, and bicycles are not allowed to use the high-speed lanes either. Tolls-roads in the interior of the country are about to be established in the very near future.
The country roads among the villages and the little towns are usually quite peaceful, sometimes without any cars, often used by carts and herds (the latter use them while going to their feeding grounds and back). The road surface in these areas may be not very smooth at some stages, potholes could also occur, but the most common annoyance is small sectional patches of repavement where it was not evened out with the old road.
Bikers can often use roadside facilities to relax - there are sites with drinking-fountains, catering establishments, stands selling fruits, vegetables or souvenirs, roadside motels, petrol stations with attached shops etc.
Roads in Bulgaria do not have emergency lanes, so riding with the cars is necessary. Main roads are usually well signed, tho many times only in Bulgarian, so make sure to buy a map with Bulgarian names. Thirdary roads and small villages are signed only in Bulgarian, and sometimes not well seen. Mountain roads commonly contain sand (left over from winter). Train tracks are not always the smoothest to cross.
Although the drivers are reckless around each other, they pose little hazard to cyclists. When passing, drivers usually move over when possible. Many of them however, have a poor attitude toward the safety of cyclists.
Truckers are of a greater concern but only when thetraffic is heavy. The farming gypsies use mules and cart, which are quite common to pass. Dogs pose no threat.
Bulgaria is known for gypsies, particularly the southern portion. According to the locals (and even other countries) the gypsies will rob you at any opportunity.
Although it is nearly impossible to travel Bulgaria without seeing gypsies, they should pose no risk to your safety as long as you use common sense. Do not leave your loaded locked bike unattended in questionable areas. Hesitate from free camping outside of the mountains.

Do not bike in the towns when dark!