I. Dadic, A. Malic, G. Kos: Ljubljanska and Slavonska Avenue- Traffic Key of the City of

IVAN DADIC, D.Sc. Traffic Planning Institut prometa i veza Preliminary Communication Kuslanova 2, Zagreb U.D.C. 625.712 ADOLF MALIC, D.Sc. Accepted: May. 29, 1998 Fakultet prometnih znanosti Approved:Dec.23, 1998 Vukelieeva 4, Zagreb GO RAN KOS, B.Eng.

LJUBLJANSKAAND SLAVONSKAAVENUE- TRAFFIC KEY OF THE CITY OF ZAGREB

SUMMARY Hrvatska bratska zajednica is about 10,550 m away from the interchange with the ring road. Thus, in a The paper analyses the urban motorway, the Ljubljanska certain way, the Street Hrvatska bratska zajednica to­ and Slavonska Avenue in Zagreb. As the key road, it is impor­ gether with Ljubljanska and Slavonska Avenue forms tant for the city of Zagreb both regarding internal and external a kind of a Zagreb urban and traffic cross. The centre traffic links. The almost ideal location of the Ljubljanska and of this cross is the geotraffic centre of the city. Slavonska Avenue has not been properly evaluated and used by the Zagreb urban and traffic designers. The traffic count, meas­ This cross is positioned approximately in the mid­ uring the vehicles speed and the analysis of the existing inter­ dle of the Dubrovnik Avenue, which is the central changes have indicated the disadvantages, drawbacks and ir­ street of Novi Zagreb. Allowing for a certain asymme­ regulalities related to the design ofthe motorway. The measures try, the Dubrovnik Avenue is connected towards the for improving the traffic flows and change ofsignalling devices south-west, from the western side by the Jadranska have been proposed and the design of interchanges has been Avenue leading towards Karlovac, Split, Rijeka, i.e. recommended. The traffic forecast for the next ten years, ac­ through the "Lucko" interchange to the Zagreb ring cording to the growth predicted by BDP, imposes urgency in re­ road. To the east, the Dubrovnik Avenue is extended alising the phases in improving the throughput capacity and by the Avenue of Savezna Republika Njemacka and safety of the traffic along this motorway. the Velikogoricka Road, which connect Zagreb with Velika Gorica and the airport, as well as further with 1. INTRODUCTION Sisak, Petrinja, Pounje and a part ofPosavlje (the Sava region), and also Zagreb with the ring road over the The Ljubljanska and Slavonska Avenue, in the "Buzin" interchange. East-West direction, passes almost through the geo­ The city of Zagreb spreads along the whole length graphical city centre itself. The historical centre of the of the Ljubljanska and Slavonska Avenue, to both Zagreb city (Gornji grad, Kaptol and Donji grad) is sides- the north and the south. The length of the city situated along its middle part, between the inter­ from the east to the west almost equals that of the change with the Zagreb ring road west of , Ljubljanska and Slavonska Avenue. Unfortunately, and the interchange with the ring road near lvanja such almost ideal position of the Ljubljanska and Sla­ Reka one to two kilometres to the north, in the exten­ vonska Avenue has not been properly evaluated and sion of the Hrvatska bratska zajednica Street. The used for the internal traffic connecting of the city of Street ofHrvatska bratska zajednica has been marked Zagreb by the Zagreb urban and traffic planners and out so that, leading from the north to the south, from designers. This is partly the result of the impossibility the Ban Josip Jelacic Square, over Zrinjevac, Glavni for consistent development of the overall urban space kolodvor (the main railway station), and between the of a country such as , whose development was buildings of the Zagreb municipal board and the Con­ for 45 years subjected to unnatural laws and regula­ cert Hall "Vatroslav Lisinski", and bridging the Sava tions. During that time the urban traffic development river, it leads to the central part of the Novi Zagreb concept of Croatia was realised in even unintention­ (the new part of the city). Therefore, the Novi Zagreb ally promoting the development of big cities at the ex­ centre is only about 2 km from the Slavonska Avenue. pense of the traffic and urban development of the Since the overall length of the Ljubljanska and Slavon­ whole. This is also partly the reason why the today's ska Avenue amounts to about 22,400 m, the Street Ljubljanska and Slavonska Avenue accommodate

Promet- Traffic- Traffico, Vol. 10, 1998, No. 5-6, 233-241 233 I. Dadic, A. Malic, G. Kos: Ljubljanska and Slavonska Avenue- Traffic Key of the City of Zagreb more vehicles (over 4,000 vehicles per day) than the - connecting the main roads and motorways of Za­ "feasible" traffic capacity, causing thus frequent and greb with the eastern Croatia (Slavonija and Hrvat­ long standstills, whereas at the same time there is the sko Podunavlje - the Croatian Danube Region), Zagreb ring road with 8,000 vehicles passing daily and Varazdin, Cakovec, i.e. Krapina, and over these the capacity of about 60,000 vehicles. roads also with the neighbouring countries of Slove­ Apart from the fact that more than 20% of the nia and Austria, Hungary, SR Yugoslavia and Bos­ overall population of Croatia lives in Zagreb, and that nia and Herzegovina. more than 30% of the vehicles and social production Without internally connecting Zagreb there may are in Zagreb, the knowledge that traffic jams make be no efficient traffic and economic linking of Zagreb Zagreb less comfortable for living and less competi­ with its surroundings, nor with the rest of Croatia and tive on the world market of economic and cultural de­ the world. Therefore, the tendency has to be towards velopment, is a reason enough for serious worries. faster inter-linking of the single parts of the city, i.e. T11e similar situation can also be found in other towards reducing the travelling time, increasing the major Croatian cities (Split, Osijek,. Rijeka). Such pol­ safety of vehicles and pedestrians, reducing the ad­ icy of urban disintegration, i.e. growth of the cities has verse effects of traffic on the environment (noise, air damaged in particular the smaller towns, villages and pollution), towards optimal usage of the urban space even whole urban regions (Lika, Dalmatinska Zagora, and reduction of transportation costs in transporting Croatian islands, part of Slavonija). For the sake of goods, and especially towards reducing the travelling comparison only, let us note that during the last inter­ time of citizens in carrying out their daily activities. war period the urban disintegration has left the Re­ public of Slovenia almost untouched. With the knowledge of these failures, and the un­ 3. ANALYSIS OF THE CURRENT limited possibilities provided by the new Croatian so­ CONDITION ciety in the Republic of Croatia, there is a chance, even over a ten-year period, for an economic turn, i.e. 3.1. The analysis of the current traffic and ur­ integration into the company of highly developed ban solutions regarding the Slavonska and European countries,. Among all the other tasks, one Ljubljanska Avenue · of the most important is the reconstruction, i.e. con­ struction of a modern traffic system. The Slavonska and Ljubljanska Avenue represents The disharmony in the previous development of the basic backbone of the urban traffic network. It at­ the traffic system of Zagreb as a whole, as well as its tracts directly the population of about 40 kn12 of city subsystems, especially the road and railway traffic, re­ area, including the city centre and the most important quires a more versatile study and proposals regarding industrial and commercial zones, which means that its future development in order to make the realisa­ the most important traffic flows in the city use this tion as efficient as possible. The paper analyses a prin­ road (source and target traffic, inner urban traffic) cipled approach to this problem with the basic charac­ Apart from being the main internal traffic connec­ teristics of the previous development and the concept tion, The Ljubljanska and Slavonska Avenue also inte­ of the traffic solution for the Ljubljanska and Slavon­ grate the city of Zagreb over the six key European ska Avenue as the urban motorway. roads not only into the Croatian road network but also into the road network of the Central Europe, as well as the Danube region and the Adriatic. 2. SIGNIFICANCE AND ROLE OF THE The basic characteristic in the development of the LJUBLJANSKA AND SLAVONSKA road traffic system, i.e. the road traffic infrastructure, AVENUE which most affects the traffic development, is present in the development through three main phases. The significance and the role of this road in the 1) the first development phase after the World War II saturation of the future traffic flows is reflected in: includes the construction of the urban motorway - internal traffic flows circulating within the city from (Slavonska and Ljubljanska Avenue), road to­ the eastern towards the central i.e. western parts of wards Krapina and Maribor, and the construction the city and vice versa, of the basic street network in Zagreb with the - connecting Zagreb with the western and north­ bridge over the river Sava in the Street of Hrvatska western parts of the counties of Zagreb and bratska zajednica, Krapina-Zagorje over the J ankomir interchange, 2) the second, post-war phase, includes the construc­ and connecting it with the eastern and north­ tion and additional construction of the road net­ eastern parts of the county of Zagreb over the work with the bridges (Most mladosti and Jadran­ interchange ski most), as well as the construction of the

234 Promet- Traffic- Traffico, Vol. 10, 1998, No. 5-6,233-241 I. Dadic, A. Malic, G. Kos: Ljubljanska and Slavonska Avenue- Traffic Key of the City of Zagreb

motorway towards Karlovac. The second part of This approach (the construction of the ring road as the phase includes the construction of the Zagreb a complete motorway), has provided the maximum ring road with the motorway towards Slavonski possible comfort for through vehicles, while the Brod, and the reconstruction, i.e. additional con­ origin-destination, especially inner urban traffic flows struction of the Ljubljanska and Slavonska Avenue have been completely neglected. 3) the third phase- ( 1980-1990) is marked by the con­ The basic drawbacks of inappropriate regulation struction and reconstruction of the road towards and traffic flows organisation are reflected in: the Airport Zagreb and Velika Gorica, construc­ - the failure of the previous investments, due to in­ tion of the semi-motorway Ivanja Reka- Popovac, adequate use of infrastructure, reconstruction of the Slavonska Avenue and the high transport costs construction of the grade-separated (segregated) - lower level of traffic safety road -railway line crossings in the western part of - low average travelling speed the city (Selska, Vrapcanska). The third phase is marked also by a substantial extension and addi­ - long waiting times at intersections tional construction of the tram traffic. - longer travelling distances and difficult orientation The basic disadvantage in the road traffic infra­ - increased fuel consumption. structure development is the insufficient throughput The regulation and organisation of traffic flows capacity of the road network in the east- west direc­ and their adequate control in the network and on the tion. This disadvantage could and had to be corrected intersections can significantly contribute to the by the construction of the Ljubljanska and Slavonska greater efficiency of the traffic system. Avenue as a real city motorway, first as a four-lane and The signal-controlled regulation, especially at the later in the future as a six-lane one. However, al­ beginning of the second phase (beginning of the though it exists as the four-lane road with two sepa­ 1970s), has started with a very complex regulation of rated carriageways, the at-grade crossings and compli­ multiple phase systems (such as e.g. the intersection of cated signal-controlled regulation, make this road a the Savska Street and the Vukovar Avenue). The traffic barrier in the east-west flows, and in the north­ same regulation models were gradually copied all over south flows as well. the Zagreb network, and partly in the Republic of Thus, apart from having one natural barrier (the Croatia as well . river Sava), Zagreb has got, apart from the railway This traffic regulation was aimed at achieving the line, one more traffic barrier. maximum traffic safety. However, the result was the

MEOVEONICA

SAMOBOA

SLAVONS

INDEX:

URBAN MOTORWAYS

PLANNED NEW ROADS

OTHER URBAN ROADS

COUNT POINT

KARLOVAC SISAK

1998 C lnst1tut prometa i veza

Figure 1 -The position of the Ljubljanska and Slavonska Avenue within the network of the City of Zagreb

Promet-Traffic- Traffico, Vol. 10, 1998, No. 5-6, 233-241 235 I. Dadic, A. Malic, G. Kos: Ljubljanska and Slavonska Avenue- Traffic Key of the City of Zagreb

complete opposite, and the Zagreb intersections are was done in order to obtain data on the average vehi­ extremely dangerous and probably present the basic cle speeds on the Ljubljanska and Slavonska Avenue. cause for unsafety in traffic. The recording of traffic was carried out by a pas­ The regulation and organisation of the traffic in senger car of standard dynamic properties. The task of the Zagreb centre, as well as the traffic regulation at the driver was to travel at the legal speed limit, and to the intersections in the wider central area of Zagreb, follow a selected vehicle considered as representative significantly reduce the efficiency of the urban public compared to other cars in the flow and regarding its traffic. method of driving in the flow, and primarily regarding the speed. 3.2. The analysis of traffic along the Slavonska The driving was done along the right traffic lane, and Ljubljanska Avenue overtaking only in specific traffic conditions (a car standing due to a breakdown, roadwork, or vehicles Since Zagreb lies primarily in the East - West di­ driving at very low speeds, such as vehicles for special rection, just like the Ljubljanska and Slavonska Ave­ operating purposes). The run itself started somewhat nue, it is possible to obtain a complete picture of the prior to the starting measuring point. Abiding by the traffic load by selecting seven section points (Figure mentioned rules, the run in the opposite direction fol­ 1 ). The picture of the traffic load would have been lowed immediately afterwards. much more accurate if the traffic flows related to this The average (mean) speed on the section between avenue had been recorded. However, such a study the Interchange Zagreb East and the Interchange Za­ would require a lot more means and time and it would greb West was 44.1 km/h, and the average speed on re­ need to be carried out as part of developing the entire turn was 43.2 km/h. traffic planning of the city of Zagreb. The results analysis ofthe traffic count and vehicle In order to obtain the data on the traffic load of the speed recording Slavonska and Ljubljanska Avenue, the through traf­ fic at the seven selected sections has been counted. It is immediately obvious that there is an extreme Similarly, the vehicles speed on the Slavonska and load of vehicles on the section of Ljubljanska Avenue Ljubljanska Avenue has been recorded in order to ob­ between the intersection with Zagrebacka (and Petro­ tain the data on average speed between the intersec­ varadinska), Slavenskog and G.Krklec (Figure 2). tions This result stands apart from the natural law of traffic flows only at the first glance. The results immediately Measuring the speed indicate that a necessary local urban road link be­ The speed on the Ljubljanska and Slavonska Ave­ tween the Vrbani, Staglisce and Jarun residential ar­ nue was measured on Tuesday, January 21, 1997. It eas with the Precko residential area is missing. Thus, it

EJA 2169 FLOW DIRECTION 2000 1873 .. 1805

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1000 1067 560 500 COUNT COUNT COUNT COUNT COUNT COUNT COUNT POINT POINT POINT POINT POINT POINT POINT CD ® ® 0 ® ® 0

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1707 1659 1677 2000 1759 FLOW DIRECTION • Figure 2 - The results of the traffic load between 3 and 4 p.m.

236 Promet- Traffic- Traffico, Vol. 10, 1998, No. 5-6, 233-241 I. Dadic, A. Malic, G. Kos: Ljubljanska and Slavonska Avenue - Traffic Key of the City of Zagreb borders with absurdity that all the traffic flows con­ 3.3. The analysis of traffic flows crossing the necting Precko and Savska Opatovina with other parts Ljubljanska and Slavonska Avenue of the city south from the Ljubljanska Avenue, have to pass along Ljubljanska Avenue. To make it even Since the peak daily load on the mostly loaded sec­ worse, this section of Ljubljanska Avenue receives tion of the Slavonska Avenue (the Hrvatska bratska also partly the flows from Spansko towards Rudes and zajednica underpass) amounts to about 42,000 (EJA) Voltino residential areas. conditional passenger cars, it was estimated that the The middle part of this road has a similar situation. traffic crossing the Ljubljanska and Slavonska Avenue Thus Srednjaci and Knezija have a very bad connec­ ranges between 80,000 and 100,000 vehicles. tion more to the south of the Ljubljanska Avenue. The The certainly most intensive north-south traffic situation is extremely unfavourable because the flows are those using the following streets: Hrvatske Cvjetno naselje area is not connected to Savica, nor bratske zajednice, Savska, Ddiceva, Heinzelova, Sel­ Savica with Radnicka cesta south of Slavonska Ave­ ska and Grada Gospica, HrgoviCi - Drvinje, Petro­ nue. Moreover, because of the bad interconnection of varadinska- Zagrebacka, Gustava Krkleca- Slavenska housing estates located between the Slavonska Ave­ and Culinecka. The flows are often zigzagged (turns) nue and the Railway Line, Culinec, Sesvete, Vu­ due to the Jacking connections between the city dis­ komerec, Trnava and Pescenica, and the unsolved tricts north and south of the Ljubljanska and Slavon­ problems in the north-south communications due to ska Avenue. the insufficient number of grade-separated crossings The pedestrian flows crossing the Slavonska and below the Railway Line, it is easy to find reasons for Ljubljanska Avenue are also of high intensity, espe­ the overload to which this road is subjected. cially near the tram or bus stops. The detailed urban By multiplying the peak load of a one-hour count plans have not paid enough attention to the vehicle by the number 11 (peak hour coefficient) will yield the and pedestrian flows crossing the Slavonska and peak daily load sufficiently reliable for determining Ljubljanska Avenue. the intensity of the daily traffic flows. Thus the total daily load at the count point number 3.4. The traffic analysis of the current inter­ 2, from 4 to 5 p.m., amounted to 3,750 x 11 = 41,250 changes on the Slavonska and Ljubljanska (vehicles per day). Avenue Taking into consideration the nature of traffic de­ velopment, the biggest number of vehicles is to be ex­ The interchanges on the Ljubljanska and Slavon­ pected at the cross section under the overpass on the ska Avenue have been constructed as interchanges Hrvatska bratska zajednica Street. There, the peak (intersections) with one, two and three levels. Unfor­ traffic load is from 7 to 8 a. m. - 38,26 x 11 = 42,086 ve­ tunately, these interchanges have not been designed hicles/day. properly, neither from the traffic nor from the urban Since the intersections on this avenue are of mixed and aesthetic point of view. Although not considered type (grade-separated and at-grade), it is obvious that here in detail, the traffic safety problem is present at the number of vehicles exceeds the throughput capac­ almost all the interchanges. ity of the road. Thus, during peak daily loads, the Apart from the interchanges with the ring road and level-of-service of this road is F, which means that six more grade-separated intersections, all the others, there are frequent and longer standstills during the i.e. intersections have been constructed as at-grade whole working day, from 6 a.m. to 9 p.m. crossings. The achieved average speeds are extremely low. With the exception of a signal-controlled intersec­ Thus the lowest speed measured on the section be­ tion, where the traffic has been regulated by two­ tween the Falerovo setaliste and the Puljska Street on phase traffic lights (Slavonska - M.Caviea), all the the Ljubljanska Avenue in the east-west direction other intersections are regulated in three or four amounts to 20 km/h, and on the section between Hein­ phases. With long cycles of about 120 seconds, such zelova Street to M.Cavica Street is 20.5 km/h also traffic regulation causes long vehicle waiting times i.e. along the Slavonska Avenue westwards. The average reduced average driving speed, lower intersection measured speed westwards was 44.1 km/h, and east­ throughput capacity (missed green time in a certain wards 43.2 km/h. The measured maximum speeds be­ phase), higher transportation costs (travelling time, tween the two interchanges amount to over 100 km/h, number of stoppings, fuel consumption), reduced traf­ indicating that there is a lot of speeding, high maxi­ fic safety and increased adverse effect on the environ­ mum speeds, long waiting times and low average ment. speeds, especially in peak hours. It can be said that The visible part of the traffic light equipment has these conditions are simply "perfect" for reducing been designed inconsistently. Thus, some intersec­ traffic safety. tions are fitted with lanterns over each traffic lane, and

Promet- Traffic- Traffico, Vol. 10, 1998, No. S-6, 233-241 237 I. Dadic, A. Malic, G. Kos: Ljubljanska and Slavonska Avenue- Traffic Key of the City of Zagreb at some intersections there is only one (with repeat­ The interchange of Ljubljanska and Slavonska ers) on the approach. Avenue and the Savska cesta, apart from having too Except for the grade-separated intersection of the narrow lanes compared to the volume of the traffic, Slavonska Avenue and the Hrvatska bratska zajednica with a narrow dividing median, it is a great pity that Street and the interchanges of the Ljubljanska - Sla­ the "tunnel" underneath the Savska cesta has not been vonska Avenue with the Zagreb ring road, there is no constructed as two tunnels with three lanes each, in­ other interchange that might claim to have been well tended for the calculated speed of 80-100 km/h and designed regarding traffic. the traffic lane width of 3.5 m. All these interchanges, except the interchange for The upper urban level with the Savska cesta has Jankomir and the one with Ddiceva Street, have traf­ been intolerably badly designed. Thus, the traffic at fic signal intersections at the urban level, with traffic that level flows in four phases causing nervousness flowing in three or four phases. Regarded from this as­ both in motorists and pedestrians due to long waiting pect, such solutions are seldom found in the world times and many other disadvantages. Moreover, it has traffic and urban practice. Thus, the four-phase traffic not been planned, and now it would prove difficult, to regulation system remained even after the Ljubljanska add at the upper level the lanes for half-turns that and Slavonska Avenue with Savska have been trans­ would simplify the connections of the neighbouring formed into a two-level intersection. Although de­ infrastructure connected to the traffic network, along pendent on traffic, it causes traffic jams and therefore, the connecting lanes to the Slavonska, i.e. to the Ljubl­ is not co-ordinated neither along the Savska Street nor janska Avenue. the Ljubljanska and Slavonska Avenue. The interchange of the Slavonska Avenue with the The interchange of the Ljubljanska Avenue with Hrvatska bratska zajednica Street has been conceptu­ the access road to the cargo terminal Jankomir has allywell designed (Figure 3). The quasi-roundabout at been constructed as an extra-urban interchange. The the urban level should have been of greater dimen­ drawback lies in the fact that the urban development sions. It is also a pity that the design of the interchange plans will necessarily seek connection to the space had not foreseen the adding of two lanes along the Sla­ south of Ljubljanska Avenue precisely through this in­ vonska Avenue for the through traffic stream. terchange. It is also difficult to understand why there are lan­ The interchange of the Ljubljanska Avenue with terns above every traffic lane on the intersection ap­ the Selska cesta has been designed by partly lowering proach at the urban level, and only one on exit. the grade (concave curve) and rising of the grade (con­ Moreover, the exit-entry arms of this intersection have vex curve) of the Selska. The basic drawback of this in­ to be opened towards the residential area Trnje, i.e. a tersection is its urban level at Selska. There is no possi­ part of the residential area between the HTV (Croa­ bility for the traffic coming down the exit arms along tian Television) Building and the Sloboda Bridge. the Ljubljanska Avenue to continue straight (city bus), This would simplify the traffic flows. entrance to objects on the entry arm or exit from the The interchange of M.Drzica and the Slavonska objects along the exit arm. Moreover, due to the badly Avenue is the only three-level intersection. It is no se­ designed intersection at the Selska cesta, the signal­ cret that it can be regarded as a complete traffic, urban controlled traffic is regulated in three phases. and architectural failure. Is there anywhere in the world a three-level inter­ section, with the traffic approaching and departing through signal-controlled intersections at a distance of 500-1,000 m? This project is a true example of the ecological vio­ lence against the human environment (gases, noise, ambient devastation), and without any advantages for the traffic. On the contrary, this solution has damaged both the traffic flows and the traffic safety a lot. As part of long-term urban traffic development planning, this interchange would have to be com­ pletely redesigned and reconstructed both from the traffic and urban point of view, and the so-called "left turn lanes" (the third level) must be removed. The interchange of the Slavonska Avenue and the Grad Gospic Street; the lower urban level of this inter­ Figure 3 - An example of a conceptually well change has not been designed properly. At that level · designed quasi-roundabout there is a tram line on the west side of the Grada

238 Promet- Traffic- Traffico, Vol. 10, 1998, No. 5-6, 233-241 I. Dadic, A. Malic, G. Kos: Ljubljanska and Slavonska Avenue- Traffic Key of the City of Zagreb

Gospic Street. At both signal-controlled intersections traffic connection along the Ljubljanska and Slavon­ the traffic flows in three phases, additionally prolong­ ska Avenue are probably double the amount of the ing the waiting times and increasing the transportation stated ones, due to the daily long traffic standstills costs. whose key lies precisely and mostly in eliminating the Finally, after having analysed the single- or two­ traffic standstills in the Slavonska and Ljubljanska i.e. three-level interchanges one can only conclude Avenue. that there is an inconsistency present together with It should be noted that the parallel connections various traffic and urban philosophies in the realisa­ which do not exist between the residential areas north tion of the traffic and urban characteristics of the and south of the Ljubljanska Avenue, are of extreme given interchanges. importance. Their construction would require addi­ tional 200 million Kunas. 3.5. The analysis of traffic costs at the Slavon­ ska and Ljubljanska Avenue 4. THE FUTURE TRAFFIC REQUIRE­ Such traffic load and the applied solutions cause a MENTS ON THE SLAVONSKA AND lot of stopping and long waiting times of vehicles. It LJUBLJANSKA AVENUE would be very difficult to estimate all the costs in­ volved in such traffic solutions, therefore, by using a simple but consistent approach we shall try to provide It is extremely difficult to forecast the traffic re­ a sufficiently reliable estimate about quirements on the Slavonska and Ljubljanska Avenue 1. the number of vehicle stopping related to traffic without the assumed input data such as elements of flows along Slavonska and Ljubljanska Avenue the traffic network and its quality, north and south of and crossing Slavonska and Ljubljanska Avenue, this road. The traffic demand would probably increase instantaneously by more than 20% if this road - street 2. the fuel consumption caused by these stoppings were quickly reconstructed into an urban motorway. 3. longer travelling times, i.e. lower average speed ex­ pressed through higher fuel consumption and the The forecast of the traffic demand for the current price of average driver's and passengers' hour of traffic solution over a period of the next 5 years, has waiting, been made under the assumption of no major changes in the traffic network. For the period of 5 to 10 years, it Thus, 30,000 vehicles due to an average of 8 stop­ is to be assumed that the residential area Precko will pings I vehicle daily, have to come to a stop 240,000 be connected across Jarun to the Prisavlje Street and times. These vehicles consume therefore additionally further across Savice to Kozari put, i.e. that the resi­ 13,680 litres of petrol daily. The vehicles (100,000) dential areas Spansko and Voltino naselje will be con­ crossing the Ljubljanska and Slavonska Avenue have nected. Over the ten-year period, at the most, all vehi­ to come to a stop 100,000 times and therefore con­ cle - pedestrian intersections at the Ljubljanska and sume 3,200 litres of fuel per day. Slavonska Avenue from the Culinecka Street to the At the average fuel price of about 4 Kn/lit the stop­ Gustava Krkleca Street (Spansko), should be trans­ pings consume daily 16,880 litres of fuel or 67,520 formed into grade-separated ones. Kunas. For a total of 340,000 stoppings, 340,000 min­ utes are wasted, i.e. 5,667 hours or 396,690 Kunas During this period the Vukovarska Avenue should daily. Thus the daily costs due to fuel and wasted time be extended across Krapinska to Selska, i.e. Boron­ amount to 464,210 Kunas or 170 millions Kunas a gajska Road. year. Over the following 5 years, the average daily traffic If other costs related to traffic safety, environ­ will increase at a rate of 5% (in accordance with the in­ mental protection, and additional damage and de­ crease of the gross national product), i.e. within 5 struction of the road and vehicles are added to the be­ years it will increase by about 28%. This means that fore mentioned costs, the cost of such a traffic solution the traffic between Savska and Ddiceva Street will in­ for the citizens of Zagreb and Croatia, its economy crease from about 42,000 to 54,000 vehicles. On other and state, cost more than 200 million Kunas a year or sections it will be reduced and at the end sections near about 37 million US$. The five-year losses caused in the interchanges in Ivanja Reka and Jankomir, it will this way are much higher than the investments neces­ amount to 30,000 vehicles/day. sary for the reconstruction of the Ljubljanska and Sla­ It will be very difficult to accommodate this kind of vonska Avenue as the fast urban road i.e. urban traffic flow along the existing road. In order to make it motorway which is estimated to an amount of about at least partly possible, the three- and four-phase traf­ 760 million Kunas, i.e. 130 to 140 million US$. fic regulation system should be changed into a two­ It should certainly be mentioned and pointed out phase one (with, if necessary, post-phase flow of left­ that the actual costs due to the lack of high-quality turning vehicles).

Promet- Traffic - Traffico, Vol. 10, 1998, No. S-6, 233-241 239 I. Dadic, A. Malic, G. Kos: Ljubljanska and Slavonska Avenue- Traffic Key of the City of Zagreb

If traffic increase is assumed over the following 5 tensity flows connecting through these intersections years as well, at a rate of 5%, i.e. 28% over the period the pedestrian and vehicle streams of the north and between 2003 and 2008, then in the year 2008 about south part of the city, this road is already today com­ 69,000 vehicles/day would be passing this road along pletely overloaded in the traffic sense and it may be its central section from Savska to Drziceva Street. In said that it is at the level-of-service F, where the traffic order to make this possible, the section of the road demand is greater than supply. from Culinecka Street to the residential area Spansko The lack of good parallel links between the resi­ would have to be grade-separated and a new parallel dential areas from the southern and the northern side, connection south from Zitnjak to Precko constructed. present an additional traffic load, especially for the Assuming the traffic increase of only 3% annually, section of Ljubljanska Avenue passing through the between 2008 and 2018, the traffic on Slavonsla and city districts of Precko, Rudes, Spansko and Vrbani. Ljubljanska Avenue would increase by 34% following There is not one reason that could serve as an argu­ the year 2008, and it would amount to over 90,000 ve­ ment against constructing the Ljubljanska and Slavon­ hicles/day. ska Avenue in its full length as an urban motorway, i.e. Since this road cannot accommodate such traffic fast urban road with the following elements: intensity, a so-called North tangent will have to be 1. the calculated speed over the whole length should constructed, which will through tunnels and over via­ amount to 100 km/h, excluding only its central sec­ ducts pass along the south slopes of the Medvednica tion from Selska to Heinzelova Street where it mountain, from the New hospital area to Podsused. could be 80 krn/h, The interconnection of Ljubljanska arid Slavonska 2. The road should have four lanes, i.e. a dual car­ Avenue and their connection to the other parts of the riageway with two lanes each. At the central part of main urban network will provide the possibility of ac­ this road, the construction of grade-separated in­ commodating such increased traffic flows. In order to tersections with only four lanes (Savska, Hrvatske make it possible, the advantages offered by the railway bratske zajednice, Selska and Ddiceva Street), service to the urban and suburban transportation make the construction of this road as a six-lane one should be exploited. If this were not the case, then the extremely difficult. All the estimates of the traffic alternative would be to expand the Slavonska and demand indicate that the central section of the Ljubljanska Avenue in its central section, from the Ljubljanska and Slavonska Avenue should have six residential area of Spansko to the Culinecka Street as lanes (dual carriageway with three lanes each). a six-lane urban motorway. This problem may be in the future mostly compen­ sated by the road that would connect Jarun and 5. CONCLUSION Precko (Horvacanska Street) over Prisavlje, with Zitnjak, as well as with the change in traffic regula­ tion and extension of the Vukovarska Avenue It may be said that the ideal location of the Ljubl­ westwards and eastwards (Krapinska and Boron­ janska and Slavonska Avenue within the urban space of the City of Zagreb offers excellent possibilities for gaj). meeting the traffic requirements, i.e. traffic demands 3. in its whole length this road should be grade­ of source-target traffic flows, and for the inner urban separated for the traffic flows between Ivanja Reka traffic flows in the West- East direction as well. This is and Jankomir, both for vehicles and for the pedes­ an East - West road which passes the central urban trians. This means that the levels of all the existing area and provides the best connection of the urban north-south traffic links (vehicles and pedestrians) area over the Ivanja Reka and Jankomir interchanges should be separated. on the motorways leading to Slavonski Brad and 4. it is possible and desirable to lead all the pedes­ Varazdin, and towards Ljubljana and Maribor respec­ trian flows along this road separate from the car­ tively. By the additional connections, the Ljubljanska riageway (traffic lanes). When difficult to achieve, and Slavonska Avenue connect the city through the then it would be necessary to separate the pedes­ Buzin interchange with Sisak, Petrinja and Pounje, trian flows from the vehicle flows by a minimum 2 and through the Lucko interchange by motorway with m wide protective strip. Karlovac, Rijeka and Split. 5. all the intersections should be designed in two lev­ The Ljubljanska and Slavonska Avenue has been els, and the current so-called "left turn lanes" (the already constructed as a four-lane urban road with third level at the Slavonska Avenue intersection) dual carriageway separated by a median. Just a short should be eliminated as part of a whole traffic re­ section of this road with the Jankomir bridge across design of this interchange in the future the river Sava has two lanes. 6. since (as a necessity) the urban public bus trans­ Unfortunately, due to the maximum number of port will start using the Ljubljanska and Slavonska at-grade intersections (excluding 6) and the high in- Avenue, the planning for grade-separated

240 Promet- Traffic- Traffico, Vol. 10,1998, No. 5-6,233-241 I. Dadic, A. Malic, G. Kos: Ljubljanska and Slavonska Avenue- Traffic Key of the City of Zagreb

intersections or near grade-separated pedestrian LITERATURE: crossings should include the planning of bus stops, 7. all the intersections at the so-called "urban level" [1) Bauer, Z.: Razvoj i planiranje prometa u gradovima. Informator, Zagreb, 1989. should be signal-controlled so that the traffic could [2) Dadic, 1.: Prilog izucavanju organizacije prometnih toko­ flow in two phases with a possible post-phase turn­ va u gradovima (Ph.D. Thesis). Saobracajni fakultet, ing left (within intersections it would be necessary, Beograd, 1988. wherever possible, to plan for the possibility of U­ [3) Dadic, 1.: Prioriteti u razvoju prometnog sustava Zagreba turning after and before the intersection, provided (original scientific paper) Bulletin, No. 6, Scientific there is physical space to realise this, and there Council on Traffic HAZU, Zagreb, 1993. should be no restrictions on traffic flows, as in [4] . Fakultet prometnih znanosti: Prometna studija za PUP the case of the grade-separated intersection of DON!! GRAD U ZAGREBU- PRIJEDLOZI RJESE­ Ljubljanska Avenue and the Selska Street). NJA I! dio, Zagreb 1991. 8. regarding the fact that this is an urban road, the [5) Generalni prometni plan grada Zagreba . Generalni lighting should be of high quality. izvjestaj. Zagreb, Urbanisticki zavod grada Zagreba, 1978. Based on this concept it is necessary (within the [6) Highway capaseparat manual. Special Report 209. revised general urban planning of the city of Zagreb Transportation Research Board. National Research and its general traffic plan), to develop a complete Council. Washington, D. C. 1985. traffic project design of the Ljublj anska and Slavonska [7] Hobbs, F. D.: Traffic Planning and Engineering. Per­ Avenue with precise phase construction gamon Press Ltd., Oxford,1974. If this road is not reconstructed systematically into [8] Institut prometnih znanosti: Prometna studija za PUP a fast urban road (urban motorway), without shoul­ DON!! GRAD U ZAGREBU Analiza postojeceg stanja I ders, within the next five years at the latest, Zagreb dio, Zagreb 1991. will daily live through even several hours of traffic [9) Kis, K., D., Zic: Donji grad - provedbeni urbanisticki standstills, and another fast urban road will be "eaten plan. Plan i program. Zagreb, U rbanisticki zavod grada up" by the transport costs and the time wasted in trav­ Zagreba, 1989. elling. [10) Korte, J. V.: Osnovi projektovanja gradskog i medugrad­ skog putnog saobracaja. Gradevinska knjiga, Beograd, SAZETAK 1968. [11 J Macpherson, G.: Highway and Transportation Engineer­ ing and Planning. Longman Scientific and Technical, UVBLJANSKA I SLAVONSKA AVENIJA- PROMET­ UK, 1993. NI KL.JVC GRADA ZAGREBA [12) Malic, A.: Geoprometna obiljeija svijeta. Nakladna kuca "Dr. Feletar", Zagreb, 1995. U radu je analizirana gradska autocesta Ljubljanska i Sla­ (13] Mumford, L.: Grad u historiji. Naprijed, Zagreb, 1968. vonska Avenija u Zagrebu. Kao kljucna cesta, vaina je za grad Zagreb u smislu unutarnjeg i vanjskog prometnog povezivanja. [14) Projekcija razvoja javnog gradskog prijevoza putnika u Zagrebu (analiza stanja u javnom gradskom prijevozu Gotovo idea/an poloiaj Ljubljanske i Slavonske avenije zagre­ backi urbanisticki i prometni projektanti nisu na pravi naCin do putnika i projekcija razvoja). Zagreb, Zagrebacki elek­ sada valorizirali i iskoristili. Brojanjem prometa, snimanjem tricni tramvaj, 1984. i 1990. brzina /...-retanja vozila i analizom postojecih cvorova autoceste [15) Tonkovic, K.: Promet u viSe razina. Skolska knjiga, Zag­ ukazano je na nedostatke, propuste i nepravilnosti pri oblik­ reb, 1981. ovanju autoceste. Takoder su preporucene mjere za pobolj­ (16] Vuchic, V. R.: Urban Public Transportation . Prentice - sanje vodenja tokova, izmjene signalizacije i date prepontke za Hall, New Jersey, 1981. oblikovanje cvorova. Prognoza prometa u iduCih deset godina, [17] Wright, P. H., Paquette, R. J.: Highway Engineering. 5

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