Road surface marking | EPFL Graph Search

Road surface marking is any kind of device or material that is used on a road surface in order to convey official information; they are commonly placed with road marking machines (also referred to as road marking equipment or pavement marking equipment). They can also be applied in other facilities used by vehicles to mark parking spaces or designate areas for other uses. In some countries and areas (France, Italy, Czech Republic, Slovakia etc.), road markings are conceived as horizontal traffic signs, as opposed to vertical traffic signs placed on posts. Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians. Uniformity of the markings is an important factor in minimizing confusion and uncertainty about their meaning, and efforts exist to standardize such markings across borders. However, countries and areas categorize and specify road surface markings in different ways—white lines are called white lines mechanical, non-mecha

Effects of hard shoulder lanes configuration on driver’s behaviour

Jade Chapoton, André-Gilles Dumont

Nowadays, reassignments of hard shoulders into traffic lanes are spreading across Europe. This traffic management measure allows to respond to the growing saturation of high-capacity roads.In Switzerland, the first stretch to be equipped in such a way was opened in 2010. This article aims to highlight the impact of specific road marking and the configuration of the freeway section or stretch on the users’ behaviour. A presentation of the active hard shoulder lane system and of its geometric specificities are approached in detail. The users’ perception of the system, the lateral position of vehicles across the different lanes and the behaviour of motorists in the motorway entrance and exit areas were studied. It was thus underlined that the geometric specificities of the hard shoulder lane could hinder some users who were therefore reluctant to use that lane. This is one of the reasons for the inferior rate of use of the hard shoulder lane as compared to that of the right lane on a conventional three lane motorway. The final destination of motorists also plays an important role in the choice to use that lane, especially in the entry and exit zones of the system. The lateral position of vehicles in the hard shoulder lane is also influence by its marking peculiarities, with a more centred positions for vehicles in this lane than in other lanes of the stretch.

2014

Déformations des couches bitumineuses au passage d'une charge de trafic

Jonathan Perret

Undertaken in the field of design methods for flexible pavement, the present study focuses on the introduction of traffic loads, applied mainly to mechanistic empirical methods. In such research, strains due to traffic loads — calculated by pavement modeling based on linear elastic theory — are used for the evaluation of the life duration of the pavement. Real traffic loads on pavement vary significantly according to their intensity as well as their application modes. Our work aims to evaluate the relevance of the simplifying assumptions used in modeling to determine which parameters used in the description of traffic loads have more influence on the strains in flexible pavements. The study is chiefly based on experimental data. Strain measurements were made on several road structures, varying the main parameters of traffic loads, i.e. load intensity, inflation pressure of the tires and type of wheels. These measurements were carried out at various temperatures. Two structures featuring contrasted rigidities were modeled according to the French design method for flexible pavement. The horizontal strains exerted on these structures were studied at two depths : the bottom of the base course and the bottom of the wearing course. Then, experimental data were systematically compared with the modeling results. Strains at the bottom of the base course were both analyzed related to their maximal value — which corresponds to one of the design criteria used in mechanistic empirical methods — and as signals corresponding to the strain recordings in one given point during the passage of a traffic load. Analysis of maximal values allowed an evaluation of the influence of the studied load parameters and lead on to solutions to include them in calculations for equivalent traffic. The study of strain signals resulted in the definition of values allowing to express strain variations in function of time. The said values apply principally to notions like strain rates and the definition of frequencies that will best model strain variation in time with a sinusoidal curve. Such frequencies are obtained by decompositions in Fourier series. A relation between load speed and frequency has been defined. At the bottom of the wearing course, the study focused on strain signals only, with strange variations — which have been called "irregularities" — appearing in the horizontal strains at low depth. The scrutiny of these irregularities showed that bituminous materials located near to the road surface of flexible pavements are paradoxically more stressed horizontally than vertically. A situation that tends to link the behavior of bituminous layers in flexible pavements to the performance of a slam structure. Analysis of strain signals was supplemented by linear viscoelastic modeling based on Huet's model. If introducing the viscoelastic behavior of the bituminous layers showed no notable improvement in the quality of modeling, it nevertheless highlighted the necessity to model the pavement structure as a whole. Stress analysis underlined the effects of interactions between layers following different patterns of behavior and the importance of the interface conditions between these layers. Finally, the influence of the real vertical load pressure distribution on stress and strain in bituminous layers has been evaluated with elastic modeling. Variation of the loading conditions showed little effects on stress and strain distribution in the bituminous layers.

EPFL2003

Experimental study of Ni3Al slip traces by atomic force microscopy: an evidence of mobile dislocation exhaustion

Joël Bonneville

Slip markings produced on the surfaces of Ni3(Al, Ta) single crystals, plastically deformed at various temperatures in the flow stress anomaly domain, were examined by atomic force microscopy (AFM). A dominant feature is that for all investigated temperatures, the slip traces are rectilinear and correspond to the primary octahedral glide plane. In addition, their lengths drastically decrease when the temperature is raised. This latter result is interpreted as a strong increase of the exhaustion rate of mobile dislocations with increasing temperatures. The consequences of these results in the understanding of Ni3Al flow stress anomaly are discussed.

2004

Déformations des couches bitumineuses au passage d'une charge de trafic

Jonathan Perret

EPFL2003