1. Tendencies of Car Parking Systems for Sofia, Bulgaria Prof. Assoc., Dr. Vikenti SPASSOV Chief of Department Logistics of engineering University of Transports T. Kableshkov, 1574 Sofia, BULGARIA e-mail : vspassov@vtu.bg tel : +359 2 9709 243 ; +359 2 9709 312 ; fax : +359 2 9709 242vspassov@vtu.bg Master eng. Krasimir Krastanov – Ph.D. student University of Transport, 158 Geo Milev str., 1574 Sofia, Bulgaria E-mail: krasi_krastanov@yahoo.comkrasi_krastanov@yahoo.com Tel: +359 2/ 9709 312 Mobile: +359 888/371 692

2. INTRODUCTION The limited area in urban zones, the organization and safety of the increasing traffic have determined the necessity of construction a new parking systems. It is very important the dimensions of the automated parking garages to be optimum in order to ensure full maintenance of the mechanized systems for parking i.e. optimum usage of their productivity.

3. Present parking situation in Sofia The central city area shows the highest degree of concentration and also contains the highest concentration of (office) working places. The parking situation can be characterized by an excessively high occupancy, inadequate enforcement of the local ordinances that cannot sufficiently cope with parking problems and parking behavior in Sofia. From 22 000 parking places, on average, nearly 21 000 vehicles occupy these places, implying that the overall parking occupancy in the inner city is excessively high - 95.4%.

4. Parking Supply, Demand and Occupancy Rate in the City Center (During the Average Weekday Daytime Hour)

5. There are 8 covered parking lots on the territory of Sofia, which are the property of the city municipality and are being managed by Parking lots & Garages. Key parameters for the future unrestrained demand in Sofia are as follow: - By the end of 2005 23,500 public parking places, which include: 2,500 short-stay parking places - By 2015 35,250 to 36,850 public parking places, which include: 4,200 short-stay parking spaces

6. Short Description of the so-called Blue Zone in Sofia - The Blue Zone has been established in Sofia since October 1989. - The Blue Zone has around 4000 parking places (425 of them are official subscription) located in about 25 streets and few squares. - The short-term paid parking in a blue zone is allowed for cars and small trucks weighing up to 2.5 tons, and vans with up to 12 seats. - The parking payment is settled in advance by a talon that has to be put at the windscreen. - After the Blue Zone service was set up, the duration of parking is shorten from 6.5 hours to 3 hours. Official subscription There are 750 parking places used as official subscription and 300 subscribers. Most of the places are located in the Blue Zone – 425; 277 ones – in the center zone and 48 ones – in the rest of the city.

7. A good decision is to be built automated parking systems for cars preferably served by stacker cranes /see fig.1/, that are the basic element of the automated warehouse systems. Fig.1 Some proposals for solving of parking problems

8. The main advantages of the automated parking systems served by stacker crane in comparison with other systems are: - optimum use of the available space, - minimum room of a parking automobile, - no need of platforms and staircases, - module principle of building, that meets the requirements of the clients, - shortening the time needed for building a parking system, - less time for parking and forwarding because of the high traveling speed of the stacker crane and simultaneously vertical and horizontal movement and so on.

9. A four column stacker crane for long size materials /cert. No.32903, designed by the Scientific-research laboratory for material handling machines and systems at the Higher School of Transport in Sofia and by INTERSKLAD Engineering Ltd, Sofia / Fig.2 – Four column stacker crane for long size materials

10. Optimization of the operating cycle In general, the theoretical hour productivity of the cyclic operation machines such as stacker cranes can be determined : П о = N. i = (3600/ Tc ). N, number/h / 1 / where, N – number of cars; i - number of cycles per hour; Tc - duration of the operation cycle,s The operating cycle of the stacker crane and its movements can be illustrated in the diagram on the next figure. Fig. 3

11. CONCLUSIONS The future belongs to the automated parking - garages and the efforts made in this direction account for the investments. Automated parking garages are better decision from the social point of view. For example the owners of cars who park their cars in parking – automat are forced to pay higher parking charges. This is extremely important in order to shorten the time for servicing a single cell for parking, which is a basic criteria in building automated parking systems for cars.

12. Thank you very much for your attention