2012 International Conference on Traffic and Transportation Engineering (ICTTE 2012)
IPCSIT vol. 26 (2012) © (2012) IACSIT Press, Singapore
Bypasses – Tactical Solutions for Sustainable Development of Cities in
Romania
Gabriela Mitran, Sorin Ilie+, Ion Tabacu, Viorel Nicolae
University of Pitesti, Romania
Abstract. The lack of highways, the preponderance of the roads with two lanes, the transition of the cities
by national roads used by long distance traffic, the increasingly higher growth of traffic, both for transport of
goods and people at the national level, but also in transit, are the major features of the road transport in
Romania. Given the characteristics of the road network previously listed, the aim of this paper is to highlight
the need of building bypasses for the Romanian cities crossed by national roads in terms of sustainable
transport. The case study is conducted for a medium sized city in Romania, Bistrita, transited the European
Road E58 which connects Hungary and Republic of Moldova. The method used to determine the size and the
structure of the traffic flows throughout the road network of the city in the situations with and without bypass
consist in achieving a transport model using VISUM software. Using the methodology of calculation
approved by the European Environment Agency in the CORINAIR project and the characteristics of vehicle
fleet at national and Bistrita-Nasaud county levels, by simulation were determined the variation curves of the
main emission factors (CO, NOx, C6H6 and PM10) in both analysis scenarios (with and without bypass). The
results after simulations denote a decrease of 10 % of the volume of emissions associated with emission
factors CO, NOx, C6H6 and of 20 % for PM10. These results recommend the construction of the bypasses as
tactical solutions for sustainable development of the cities in Romania.
Keywords: bypass, modeling, air pollution, congestions, long distance traffic.
1. Introduction
The main road network in Romania is composed predominantly by roads with two lanes, classified in
national, county and village roads. The national roads which overlapping the PanEuropean corridors 4 and 9
belong to European roads category. The total length of the national roads is 15680 km. The length of the
highways in Romania is 312 km, representing a density of only 1 km / 1000 km2, which is a very low value
in comparison with the European average of 14 km / 1000 km2 [5].
The road traffic growth, with 3.5% / year from 2000 to 2011, according to data published by the
Romanian National Company of Motorways and National Roads [4], coupled with forecasted traffic
demands for the next years, put a considerable and increasing pressure on the road network. The situation is
worsened by the following deficiencies:
• almost all households located in the neighborhood of a major roads have direct access to them, which
creates conflicts between different types of traffic, and between traffic and the needs of the local
communities;
• the localization of important road segments with high international and interregional road traffic in
rural and urban housing zones;
• the existence of over 400 railway level crossings in the national road network;
• the exceeding of the road capacity in the vicinity of major cities.
+
Corresponding author. Tel.: 0040722655228; fax: 0040348453150
E-mail address: sorin.ilie@upit.ro.
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Given the national road network deficiencies, the lack of highways at the present moment and the
possibility to consider these to a long-term forecast level, for reducing the negative issues in the future, it is
recommended to build bypasses for the cities that are transited by the European and national roads. The
transit traffic through those cities is affected by circulation with low speed and then it affects the circulation
in downtown, contributing to the congestion, it affects the traffic safety and it contributes to air pollution in
the city center.
The solution envisaged (building the bypasses), facilitates the separation of the traffic flows, so that the
transit traffic be directed to the bypasses.
This paper present a case study highlighting the benefits that are obtained in the construction of a bypass
for Bistrita Municipality, over the street network which overlaps the European Road E58, which connects
two important regions of the country, Transylvania and Moldavia, and more on the border between North West of the country, with Hungary and the North - East, with Republic of Moldova.
2. Bistrita Municipality
Bistrita, the main city of the Bistrita-Nasaud county and a medium city in Romania, with a population of
81259 inhabitants (according population census conducted in 2002 [3]), is the center of polarization of the
social and economic activities at the county level.
The main road for access in Bistrita is the European Road E58 (DN17) linking Transylvania and
Moldova. The transit trips through and the penetration trips to Bistrita, and also the trips generated by the
needs of the city are made mostly by road, which leads to high values of traffic on the city roads.
3. Traffic model for Bistrita Municipality
3.1. Traffic model – base year 2011
The method applied for estimation of current traffic flows on the whole road network of Bistrita is the
specific transport model using VISUM, software system for transport planning, travel demand modeling and
transport networks management.
The major graph of street network contains the boulevards and the main streets of the city. Currently,
there is a street that had the ring road function, facilitating the movement between the city neighborhoods
and the industrial zone districts, but over the past decade there have been recorded significant changes in the
functions of the neighboring land use near this infrastructure and were developed residential neighborhoods,
the ring road being drawn into the urban space. The transit traffic consisting of commercial vehicles is still
directed to this street, but it crosses residential districts, and traffic speed is restricted to 50 km/h. For cars in
transit is allowed the access through downtown, most of the vehicles in this category crossing the city on V –
E direction (Figure 1) (the bars are proportional to the number of cars that travel between any two pairs of
zones).
Fig. 1. The chart of the traffic relationship for cars in transit.
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Zoning the territory of influence was made so as to obtain more homogeneous traffic zones in terms of
economic and social functions. Thus, resulted 50 traffic zones, 30 zones within the urban area, 14 adjacent
zones and 6 external zones corresponding to the points of the boundary area of influence for Bistrita,
expressing the transport potential of the localities served in relation to this transport pole by the national and
county roads that penetrates the locality.
The methodology applied for estimation of transport demand was based on the classic ”four steps” model:
trip generation, trip distribution, mode choice and traffic assignment on the considered network [1].
The calibration of the values resulted from the simulation was performed based on traffic data recorded
in 37 survey points and 3 origin – destination survey points. The final traffic flows for light duty vehicles
(LT), medium duty trucks (MT), heavy duty trucks (HT) and passenger cars are represented in the Figure 2
(the bars are proportional to the number of vehicle in each category).
Fig. 2. The traffic flows.
3.2. Traffic model – forecast year 2021
Fig. 3. Forecasted traffic flows.
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The future traffic flows (Figure 3) are obtained by confronting the forecasted transport demand to the
future horizon for which is realized the analysis and the transport supply materialized through the transport
network at the same time horizon forecast (Figures 4 and 5).
Fig. 4. Forecasted traffic flows.
Fig. 5. Data needed for transport demand forecast.
4. The estimation of pollutant emissions in Bistrita Municipality
By using the computing methodology adopted by the European Environment Agency in the frame of
CORINAIR project and data about the car park structure at national and Bistrita-Nasaud county levels, in
terms of the European Commission's standards on emissions of pollutants CO, NOx, C6H6 and PM10 there
were determined the variation curves of the indicated pollutants factors, depending on the speed for the
following vehicle categories: passenger cars, light duty vehicles, medium duty trucks and heavy duty trucks
(Table 1).
Vehicle
categories
Passenger
cars
Light
duty
vehicles
Medium
duty
trucks
Heavy
duty
trucks
Emission
factors
CO
Table 1. Emission factors [2].
Emission
Variation functions
factors
NOx
0,0019 ⋅ v 2 − 0,2641 ⋅ v + 10,699
Variation functions
0,00007 ⋅ v 2 − 0,0063 ⋅ v + 0,6579
C6H6
0,2009 ⋅ v −0 ,7091
PM10
0,00001 ⋅ v 2 − 0,0015 ⋅ v + 0,0726
CO
15,8⋅ v−0,6945
NOx
0,0009 ⋅ v 2 − 0,121 ⋅ v + 4,757
C6H6
0,6531 ⋅ v −0,8774
PM10
2,7241 ⋅ v −0 ,707
CO
16,965 ⋅ v −0, 7447
NOx
31,268 ⋅ v −0 ,5185
C6H6
0,5813 ⋅ v −1,0301
PM10
1,8911 ⋅ v −0, 736
CO
25,016 ⋅ v −0, 6945
NOx
49,212 ⋅ v −0 , 6274
C6H6
0,8046 ⋅ v −0,8774
PM10
11,272 ⋅ v −0, 724
5. Results and conclusions
The simulations performed in conditions with and without bypass at the level of 2021 forecast year
indicate the reducing of air pollution in downtown area with 10% for emission factors CO, NOx and C6H6
and with 20 % for PM10 (Figures 6-9) (the widths of the bars are proportional with emissions volume).
To highlight the influence of these reductions of the pollutant factors volumes on the environment in the
studied area, in Table 2 are presented the average values of the analyzed pollutants factors (CO, NOx, PM10
and C6H6) estimated in the central area of Bistrita Municipality in the 2021 forecast horizon in case there are
no bypass, at the level of an average day of the year.
Table 2. Emission factors volume.
Emission factors
Volume [g/km]
Emission factors
Volume [g/km]
CO
262630
NOx
18257
C6H6
881
PM10
1983
The results mentioned above argue the need to build bypasses for sustainable development to Bistrita
Municipality in terms of transport.
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The methods and methodologies applied in this case study, in chapters 3 and 4 for estimation the traffic
flows and the air pollution can be applied to study the construction of bypasses opportunity for any city in
Romania, which is transited by national or European roads.
Fig. 6. The variation of CO pollution factor.
Fig. 7. The variation of NOx pollution factor.
6. Acknowledgements
This work was partially supported by the strategic grant POSDRU/88/1.5/S/52826, Project ID52826
(2009), co-financed by the European Social Fund – Investing in People, within the Sectoral Operational
Programme Human Resources Development 2007-2013.
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Fig. 8. The variation of C6H6 pollution factor.
Fig. 9. The variation of PM10 pollution factor.
7. References
[1] J. de Dios, Ortuzar and L., Willumsen. Modelling transport. 3rd edition. John Wiley & Sons. London, 2001.
[2] L., Ntziachristos, Z., Samaras. Emission Inventory Guidebook – Road Transport. European Environment Agency
(EEA), 2009.
[3] http://www.insse.ro - Institutul Na ional de Statistică.
[4] CNADNR, http://www.cnadnr.ro/
[5] Eurostat. Panorama of Transport. ISSN 1831-3280. Luxembourg, 2009.
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