Vehicle swept path analysis presents an essential step while working on at-grade intersection and roundabout designs. Following the intensive development of computer-aided design (CAD) software in the past two decades, numerous CAD-based computer programs for vehicle movement simulation have been developed and commercially distributed. The accuracy of these simulation programs is usually verified by conducting experimental field tests in which real movement trajectories of design vehicles, equipped with global positioning system (GPS) receivers, are recorded. This paper proposes an improved methodology for retrieving vehicle movement trajectories from collected GPS data. The proposed methodology reduces the trajectory inaccuracy resulting from pavement grading characteristics and the inability to accurately install GPS receivers in relation to streamlined vehicle body. Results of field experiments show that the reduction of positioning errors in the horizontal projection is not smaller than 50.0 mm compared with previous studies.

Exits on multilevel interchange ramps present potentially dangerous spots from the point of traffic safety. Therefore, a range of vehicle restraint systems was developed to reduce the consequences of traffic accidents. Proper installation of adequate crash cushion systems requires sufficient space (length) at the point where the ramp leaves major road. To provide for an installation of such a system, the basic geometry of the exit ramp must be reconsidered, introducing the appropriate ration between the radius and transition curve.

Median represents a portion of an urban road separating opposing directions of the traveled way. Due to their function to provide enough space for separate traffic lane and storage of left-turning vehicles, the medians are highly desirable on city arteries carrying two or more lanes per travel direction. Type and dimensions of turning vehicles significantly affect the design of a median openings and median ends. The design solution and the geometry of median ends should be based on the composition of all left-turning movements occurring simultaneously at at-grade intersection. After selection of design vehicles for swept path analysis of the characteristic turning maneuvers in intersection, larger vehicles should be further checked for their ability to turn without undue encroachment on adjacent traffic lanes. The critical design parameter is the median width, especially at the ends of the median openings. Dragging paths of left-turning vehicles shape the median ends geometry. In traditional design practice established in Europe, three-centered compound curves with radii rations R1 : R2 : R3 = 2 : 1 : 3 and R1 : R2 : R3 = 2.5 : 1 : 5.5 are used to approximate dragging pahs of turning vehicles. In this paper, considering the median width, the deficiencies of the traditional design approach are revealed and new findings regarding the design of the median ends at at-grade intersections are presented.

Tunnel fire safety plays a key role in the railway operations and many procedural and\ud technological improvements have been realized in order to prevent and mitigate the fire risk. The fire\ud prevention and protection procedures can be approached through two main different strategies: the deterministic/\ud prescriptive based approach and the performance-based approach. In the study presented in this\ud paper, the possibility of application of the water curtain-based wayside fire protection system, as one of\ud the auxiliary systems for improving and upgrading the fire safety in the railway tunnels for the smoke\ud compartmentation, has been studied and analysed. A finite element-based dynamic simulation model has\ud been developed in order to simulate different fire scenarios and to assess the water curtain-based fire protection\ud system performances in terms of efficiency against the toxic smokes and gases propagation into\ud the railway tunnel. Some preliminary numerical results have been presente

Пројектовање путева осетљиво на контекст подразумева, у највећој мери, укључивање јавности у процес пројектовања, нарочито у раним фазама пројекта. Савремени трендови у пројектовању путева захтевају равнотежу између задовољења потреба транспорта и безбедности, као и потреба локалног становништва. Посебна пажња мора се посветити естетици и очувању постојећих амбијенталних целина. Ограничења која намеће окружење некада захтевају одступање од званичних прописа за пројектовање, и тада се примењују додатне мере да би се елиминисао негативан утицај на безбедност саобраћаја.