By car you cross a number of countries. Up to Vienna there are no customs and visa formalities. It is more different crossing the countries of former Yugoslavia; it is recommended to use the route Vienna-Budapest-Belgrade-Sofia.
The roads are first class, most of them highways. The distance from Vienna to Sofia is about 1,300km. Insurance has to be made in advance or paid at the border. Cars (self-drive and chauffeur driven) may be rented at the border checkpoints and in all tourist offices throughout the country.
Driving in Bulgaria
The Speed limits are:
· 50 km/h in populated areas
· 90 km/h outside populated areas
· 120 km/h on highways.
To drive in Bulgaria you can use your national license accompanied by an international Driving Permit. Road signs follow international standards. On-the-spot fines are in operation for speeding, drink driving, not having the correct documents, etc. The current fines for speeding range from 5 Levs if 20 km/h over the speed limit to 50 Levs if driving at 50km/h over the speed limit.
If you leave your passport with a hotel reception ask for a copy (or the original) if intending to drive a rental car.
The permissible blood alcohol content when driving is 0.5 per 1,000. Drivers found to have a blood alcohol level in excess of this can expect a fine and licence suspension. For tested levels in excess of 1.2 per 1,000 there is a maximum prison sentence of one year in addition to a licence suspension for up to four years. The simple rule is DON'T DRINK and DRIVE. It is also an offence to allow your vehicle to be used by people with a blood alcohol level in excess of the permissible level.
The Road Assistance Service
The Road Assistance Service provides 24-hour technical assistance on the road. In case of malfunction or accident, call 146 (or cellular 048 146). Their Central Dispatch Office is located at 3 Pozitano St. in Sofia, Tel. 980 33 08 and is open 24 hours a day. The Road Assistance Service vehicle that is closest to your location will be dispatched and should reach you within 30 minutes of your call. You may also request the traffic police to make the call to the Road Assistance Service.
International Driving Permit
An International Driving Permit (IDP) is valid for 12 months from the date of issue.
Recognised internationally, it normally allows you to drive a private motor vehicle without further formality when accompanied by a valid UK driving licence. People staying for more than one year in Bulgaria should have their driving licenses replaced with Bulgarian national driving licenses. For more information about the international driving licence visit the AA website below.

http://www.theaa.com/getaway/idp/
Useful Tips (Please also refer to the section entitled Driving & Road Safety)
Use common sense and don't park in restricted zones even if it seems as if everyone else does. The Sofia City Council is hot on the heels of their Western counterparts with yellow wheel clamps, and if that's not enough, they'll tow your car away, usually to the parking lot behind the National Palace of Culture.
It might also be useful to know that if someone flashes their lights at you it means that they expect you to get out of the way and not that they are going to let you go first. It also is also the all-Bulgarian warning: Police ahead!
Drive on the right, overtake on the left, cross only when the traffic light is green, give right of way to vehicles approaching from the right at crossroads and to buses in urban areas. Wearing of seat belts is compulsory.
Please bear in mind that horse-drawn carts, motorcycles and scooters can sometimes be found on major roads driving at night without lights. Please be very alert when driving at night.
Jaywalking is frequent. Please be very careful while driving in cities and drive as slowly as possible.
All the major international car-rental companies as well as many local ones have offices in Sofia
DISTANCES
Road distances to Sofia in km