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: [email protected]. 54 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. 55 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. 56 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). Table 1. Emission factors [2]. Vehicle Emission Emission Variation functions Variation functions categories factors factors 2 2 Passenger CO 0,0019⋅ v − 0,2641 ⋅ v + 10,699 NOx 0,00007⋅ v − 0,0063 ⋅ v + 0,6579 cars −0,7091 2 C6H6 0,2009⋅ v PM10 0,00001⋅ v − 0,0015 ⋅ v + 0,0726 Light − ,0 6945 2 CO 15,8⋅ v NOx 0,0009⋅ v − 0,121 ⋅ v + 4,757 duty −0,8774 −0,707 vehicles C6H6 0,6531⋅ v PM10 2,7241⋅ v −0,7447 −0,5185 Medium CO 16,965⋅ v NOx 31,268⋅ v duty ⋅ −1,0301 ⋅ −0,736 trucks C6H6 0,5813 v PM10 1,8911 v −0,6945 −0,6274 Heavy CO 25,016⋅ v NOx 49,212⋅ v duty ⋅ −0,8774 ⋅ −0,724 trucks C6H6 0,8046 v PM10 11,272 v 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.