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Structured road markings are becoming popular as edge line on high speed roads, ensuring night time visibility (retroreflection) during rain. These markings are often also "audio-tactile": vehicles (un)intentionally driving over it may produce much more tyre/road sound, which may be observed in the vehicle but also in the vicinity. The sound increase inside the car can be considered as a positive side effect, as it alarms the driver and may be very helpful for the prevention of "doze off" traffic accidents. The sound increase perceived outside the car however, may have a positive aspect as it can warn people on the emergency lane about the approaching vehicle, but it may as well annoy people living around. A method for the assessment of the acoustic properties of audio-tactile markings has been developed. It is mainly based on the "Close Proximity" (CPX) method, an ISO method intended for the acoustic assessment of pavements. The results of measurement campaigns with CPX trailers in Belgium and Germany according to a specially designed procedure are presented. The feasibility of the method is discussed. The research has been carried out in the frame of the standardization activities of the CEN working group CEN/TC226/WG2 "Horizontal signalization".
In Europe, in situ measurements of sound reflection and airborne sound insulation of noise barriers are usually done according to CEN/TS 1793-5. This method has been improved substantially during the EU funded QUIESST collaborative project. Within the same framework, an inter-laboratory test has been carried out to assess the repeatability and reproducibility of the newly developed method when applied to real-life samples, including the effect of outdoor weather variability and sample ageing. This article presents the statistical analysis of the inter-laboratory test results, and the values of the repeatability and the reproducibility, both in one-third octave bands and for the single-number ratings. The estimated reproducibility values can be used as the extended measure of uncertainty at the 95% credibility level in compliance with the ISO GUM. The repeatability and reproducibility values associated with airborne sound insulation are also compared with the corresponding values for laboratory measurements in building acoustics and an acceptable agreement is found.
Intelligent transportation systems have a high potential to optimise traffic flow, to increase road traffic safety and to reduce environmental pollution. Real Time Traffic Information (RTTI) systems help to achieve these targets. Beside verbal radio announcements the most used RTTI service is the Traffic Message Channel (TMC) as a part of the Radio Data System (RDS). TMC messages support drivers in their choice of efficient routes or prepare them to cope with situations on the route ahead. The main focus of the paper is on the quality of TMC messages in Germany. After a brief overview of RTTI stakeholders in Germany and their role in the German public traffic information chain the following literature analysis summarizes the state-of-the-art on traffic information quality. Then the paper gives an overview about methodology and first results of an ongoing project on traffic information quality that has been initiated by the Bundesanstalt für Straßenwesen (BASt, German Federal Highway Research Institute) in 2008. The paper describes a concept how to check all processing iterations of the traffic information chain and occurring failures. A cause-effect-analysis forms the basis of this concept to get an idea which reasons (= process) lead to which measurable effect (= quality indicator). The paper demonstrates the principle with the pre-process of the Location Code List (LCL), which is the major basis for message coding since the LCL describes all locations that can be named in a TMC message.
In most of the existing highway capacity manuals, level of service (LOS) of freeway weaving segments and ramp junctions is traditionally defined by the speed, volume or density in critical areas of merge, diverge and weaving manoeuvres. In that traditional concept several capacity values of different critical areas (merge, diverge, weaving) as well as upstream and downstream basic freeway segments within the influence areas are evaluated separately. In this paper, a new model which considers the total segment of freeway merge, diverge, and weaving as an entire object is introduced. A combined volume-to-capacity ratio is used for defining the LOS of the total segment. According to the probability and queuing theory, the volume-to-capacity ratio of the whole segment can be considered as a combination of volume-to-capacity ratios in the different critical areas under consideration. The parameters of the new model can be calibrated with field data. Those parameters are functions of the number of lanes on the freeways, the number of lanes in the on-ramps or off-ramps, the length of the acceleration, deceleration, or weaving sections. Varying the model parameters the function can be fitted to the existing capacity models for different types of weaving segments or ramp junctions. With this model, the traffic quality (LOS) can be obtained directly as a function of the volumes on the freeway and on the on-ramp or off-ramp respectively. The new model has the following advantages: a) a uniform function for all types of freeway weaving segments and ramp junctions, b) traffic quality assessment for all critical areas under investigation in one step, and c) easy calibration. The new model will be incorporated into the new edition of the German Highway Capacity Manual (HBS 201X).
Traditionally, traffic count statistics in Germany contain the so-called relevant hourly volume, which is defined as the 30th-highest hour of the year when listing the hourly volumes in descending order. When the first edition of the German Highway Capacity Manual (HBS) was prepared in 2001, the Federal Government decided that this 30th hour should be used as the basis for the level of service determination for all Federal freeways and trunk roads. While German freeways are quite well equipped with inductive loop detectors, there are much fewer counts on rural roads and almost no long-term data on urban roads. With the current redraft of the German HBS detailed advice will be given on how to estimate peak-hour demand (all vehicles and heavy vehicle portion), based on the n-th highest hour concept depending on the available traffic counts. As the HBS will be divided into three major parts: freeways, rural roads, and urban roads, three separate chapters for the peak-hour demand estimation will be provided. Whereas for freeways the task consists in finding the comparable site equipped with inductive loop detectors, for urban roads it is a matter of establishing which time periods of the year and weekdays are appropriate for manual short-term counts as estimation of the 30th hour of the year. For all kind of traffic devices the requirements on traffic demand models for level of service calculations are described.
Cycling and designing for cyclist in Germany: an overview of road safety, research and guidelines
(2016)
Cycling is considered a social, eco-friendly, pollution-free, low noise and healthy activity and mode of transportation. There are currently around 67 million bicycles in Germany. This number is expected to increase in the near future with greater use of electromotive assisted bicycles. Regarding the expected increase, there should be additional attention given to road traffic accidents involving cyclists. In 2014, 396 cyclists were killed in road accidents in Germany, which is 12 % of all road fatalities. Also in 2014, Germany reported over 78,000 injuries to cyclists. The majority of the fatalities (about 58 %) and 83 % of the serious injuries to cyclists occurred in urban areas. This paper will examine three aspects concerning cyclists. First, the paper will show the main current developments, for example the National Cycling Plan 2020, the effects of the road safety programme and provide an analysis of the German national accident statistics. Second, the paper will give an overview of the regulations, guidelines for road traffic and designing of cycling facilities. Lastly, this study will detail the current and completed research in Germany addressing cyclist. For example, the paper will discuss the topic "Accidents between Turning-off Trucks and Cyclists" Accidents between right turning trucks and straight riding cyclists often show massive consequences. Accident severity is much higher than in other accidents. The situation is critical especially due to the fact that, in spite of the six mirrors that are mandatory for ensuring a minimum field of sight for the truck drivers, cyclists in some situations cannot be seen or are not seen by the driver. Either the cyclist is overlooked or is in a blind spot area that results from the turning manoeuvre of the truck. At present driver assistance systems are discussed that can support the driver in the turning situation by giving a warning when cyclists are riding parallel to the truck just before or in the turning manoeuvre. The paper will describe the requirements for turning assist systems for trucks. The outcome of the study is an overview of the accident situation between right turning trucks and straight driving cyclists in Germany as well as a corresponding test procedure for driver assistance systems. Below are several other projects which will be investigated, too: Accident Risk and Acceptance of Traffic-Rules by Cyclists ; Safety Improvement in Terms of Using Bicycle Paths in the Opposite Direction ; Cycling in Mixed-Traffic ; Observation of Pedal Electric Cycles Riders to Identify Safety Concerns. These three aspects will provide the current situation on the topic of cyclist safety in Germany.
The high density of commercial freight transport on motorways makes it difficult for truck drivers to find safe parking places especially for longer rest periods during the night. Even though expansions have been made to satisfy the demand in Germany, overcrowding and dangerous situations still occur as a result of vehicles parking on the entrance and exit roads of rest areas. In 2005 a control procedure called "Convoy Parking" was installed at the rest area Montabaur on the A3 motorway in Germany. Convoy Parking is subject to a patent (EP 1 408 455 B1, 2007). Convoy Parking requires all drivers entering their departure time at a terminal in front of a barrier. Subsequently, on the basis of the input data, the automatically detected vehicle length and the actual situation at the rest area, a free parking row is assigned and trucks can be parked sorted. The German Federal Highway Research Institute (BASt) developed a new control procedure called "Intelligent Controlled Compact Parking" (hereafter referred to as "Compact Parking" for short) to achieve that trucks are parking in a compact way, side by side and without a driving lane between trucks. Convoy Parking and Compact Parking have a very different control procedure and appearance. While Convoy Parking assigns a parking row to the driver, Compact Parking deliberately leaves the choice of the parking row to the drivers themselves. Drivers do not have to disclose their departure time to any system and they are not stopped by any barrier because Compact Parking offers a wide range of departure times on variable message signs. Drivers ought to use the parking row where their intended departure time is offered. With the innovative system Compact Parking the capacity of an existing rest area can be quickly increased without enlarging the area. This also avoids long-term planning approval procedures and is friendly to the environment. Besides, the safety for all users of the rest area can be improved by reducing illegal parking. Compact Parking is supported by the German Federal Ministry of Transport and Digital Infrastructure (BMVI). The first installation of Compact Parking is under construction at the rest area Jura-West on the A3 motorway (Northern Bavaria). The Autobahndirektion Nordbayern (Motorway Directorate for Northern Bavaria) is the central agency to plan, build and run the motorways in Northern Bavaria and got the approval of the BMVI to realize the pilot project. BASt accompanies the pilot project and leads the implementation of the control procedure. The opening is scheduled for summer 2015.
With the introduction of the German Highway Capacity Manual (HBS) in January 2002 (FGSV, 2002), all methods for the evaluation of the performance of highway facilities were, for the first time in Germany, simultaneously updated and consolidated in a single work following the ideas of the American Highway Capacity Manual (HCM). This paper gives an overview of the new 2015 edition of the German HBS and describes the changes as for example the addition of chapters for freeway, rural roads, and major urban street facilities, comprising segments and intersections.
Accidents between right turning trucks and straight driving cyclists often show massive consequences. Accident severity in terms of seriously or fatally injured cyclists that are involved is much higher than in accidents of other traffic participants in other situations. It seems clear that adding additional mirrors will very likely not improve the situation. At ESV 2015, a methodology to derive test procedures and first test cases as well as requirements for a driver assist system to address blind spot accidents has been presented. However, it was unclear if and how testing of these cases is feasible, to what extent characteristics of different truck concepts (e.g. articulated vehicles, rigid vehicles) influence the test conduction and outcome, and what tolerances should be selected for the different variables. This work is important for the acceptance of a draft regulation in the UN working group on general safety. In the meantime, three test series using a single tractor vehicle, a tractor-semitrailer combination and a rigid vehicle have been conducted. The test tools (e.g. surrogate devices) have been refined. A fully crashable, commercially available bicycle dummy has been tested. If used correct, this dummy does follow a straight line quite precisely and it does not cause any damage to the truck under test in case of accidental impact. The dummy specifications are freely available. During testing, the different vehicle categories resulted in different trajectories being driven. Articulated vehicle combinations did first execute a turn into the opposite direction, and on the other hand, single tractor vehicles did behave comparable to passenger cars. A possible solution to take these behaviors into account is to require the vehicles to drive through a corridor that is narrow for a precise straight-driving phase and extends during the turn. Other investigated parameters are the dummy and vehicle speed tolerances. The results from this research make it possible to draft a regulation for a driver assistance system that helps to avoid blind spot accidents: test cases have been refined, their feasibility has been checked, and corridors for the vehicles and for important parameters (e.g. test speeds) have been set. The test procedure is applicable to all types of heavy goods vehicles. In combination with the accidentology (ESV 2015 paper), the work provides the basis for a regulation for such an assistance system.
Road markings are an essential component of a safe road. In particular, the optical guidance at night and under wet conditions rates high. Special surface textures of road markings can enhance the nighttime visibility during wetness, but they can lead on the other hand to noise emission during passages of vehicles and thus annoy residents. In the present study the tyre/road marking noise is analysed based on two different measurement methods for traffic noise: Several different road markings with increased nighttime visibility during wetness were overrun and the noise was determined by controlled coast-by measurements as well as close-proximity measurements. For both measuring methods the averaged A-weighted sound pressure levels were determined and an analysis of the third octave spectra was performed in order to identify annoying tonal components. The results of both measurement methods were compared with each other. Limitations of the individual measurement methods were overcome by combining the data. Properties of road marking noise depending on the texture of the marking are discussed in relation to those of road surface noise. The results will help specifying road marking texture types that ensure less annoyance and at the same time good visibility at wetness and night-time.
Rural roads (highways) in Germany have to provide both high road safety and an appropriate level of service in accordance with their function in the road network. Single carriageway rural roads often underperform these expectations. An analysis of severe accidents on rural roads found two main contributing factors. First, high or inappropriate speed leads to accidents caused by the loss of control of the vehicle. Second, unsafe passing manoeuvres related to a misjudgement of sight distance, speed of oncoming vehicles or a misjudgement of the driver vehicle's acceleration capability. On the five roads where unsafe passing manoeuvres were a main contributing factor to accident occurrence, single short passing lanes (600 m to 1.2 km) were built to provide safe passing. On the remaining two-lane sections passing was prohibited by road signs and road marking. This paper investigates the effect of this design change on the accident situation and on traffic flow. The research project is based on a before/after comparison of traffic and accident data. Traffic volume, vehicle types and their velocities as well as the time gaps between the vehicles were recorded at different cross-sections. The result shows a significant improvement in road safety. This improvement was especially noted for severe head-on crashes, which were reduced to almost zero. The analysis of traffic flow on these roads pointed out that the chosen lengths of passing lanes were sufficient for safe passing and thereby reduced the need for dangerous driving behaviour. The recommendations of this research were fundamental for the determination of the design parameters of the second highest design class (EKL 2) in the new German Rural Road Design Guideline (RAL) published in spring 2013.
The paper describes the development of transitions between different safety barriers in Germany but also in the context of the European standardization. In the paper practical and impact test expriences with transitions are shown. In view of the sheer number of theoretically possible combinations of safety barriers, the demand for testing every transition, even if the connecting safety barriers differ only slightly, appears to be economically unacceptable. On the other hand the experience from accidents and also from failed impact tests shows that transitions can be a risk to traffic safety. Therefore criteria for the distinction between transitions (impact test required/impact test unnecessary) are explained. In order to distinguish transitions which do not have to be impact-tested from those that require impact tests, criteria were developed and formulated.
According to an investigation in March 2008 by the Federal Ministry of Transport, Building and Urban Affairs (BMVBS) about 14,000 truck parking spaces are missing in the near of motorways in Germany. Beside constructional enlargement of rest areas, intelligent traffic systems ought to be used to detect automatically the occupancy rate of rest areas and to provide better demand management and also to achieve an increase of capacity of truck parking spaces. The essay describes the newly developed control procedure "Compact parking", which is currently under development by German Federal Highway Research Institute (BASt). The method achieves that a number of trucks are parking in a compact way, side by side and without a driving lane between them. With the help of dynamic displays above the parking rows, the drivers receive the needful information to park their vehicle in a parking row, in which other trucks have the same or an earlier departure time. This system is able to increase the rest area capacity in short-term, more quickly than constructional enlargement of rest areas.
This article reports on a two-year study (2006 to 2008) of the distribution of de-icing salts (NaCl) applied to the road and the influence of traffic on the effective times of the de-icing salts. The research was focused on the needed resting periods of de-icing salts on road surfaces. The study used sensors installed in two lanes of the Motorway A4 in the area of the Dresden-Hellerau Highway Surveillance Center (Germany), to measure air and ground temperatures, wind speed and direction, liquid film thicknesses and residual quantities of salt on the road surface during ongoing traffic at 5-minute intervals. The authors conclude with four observations that can be useful for applying de-icing salts more judiciously: preventive spreading is only sensible if applied timely, i.e. immediately prior to icing events to be expected; the time-frame for preventive spreading on the dry road surface is maximum 60 minutes and on the moist road surface maximum 120 minutes; by increasing spreading densities in preventive spreading, this timeframe cannot be extended; it is completely sufficient if the spreading width is adjusted in such a way that the outer wheel tracks are also covered by the spreading. Distribution across the entire width of the lane will be caused by the rolling traffic within a few minutes.
Since 2005 the German In-Depth Accident Study (GIDAS) also records aspects of active vehicle safety. This is done because vehicles are fitted with an increasing number of active safety devices which have undoubtedly an influence on the number, severity and course of accidents. Accident researchers expect that collecting active safety data will facilitate to assess and quantify the impact of these and future devices. It is the aim of this paper to outline benefits and limitations associated with the recording of active safety aspects within indepth studies. An overview about possible areas where active safety data can be useful will be given. For that purpose single safety or comfort systems will be selected to estimate the effects of an accident database which includes variables associated with these systems. Questions with regard to the limitations of collecting active safety data will be addressed. Possible items are for example the usability of the data recorded, the real accident cause, the small number of relevant accidents, the time span needed to gather a sufficient dataset, the small share of vehicles equipped with a certain system or different functionalities of systems that are supposed to fall in the same category. As a result user needs for a reasonable data collection of active safety elements will be elaborated.
As the data for road weather stations is used for online traffic control within section control systems, it is very important for the efficiency of the traffic control systems to be based on reliable data of a high quality. Therefore, a Test Site for checking the quality of road weather stations was established near Munich in Germany in 2003 and has been operational since then. In close co-operation with all participants (sensor manufacturers, road authorities, German Federal Research Institute, research and consultancy bodies), the overall goal was to improve the sensors" quality as well as to establish methods to detect failures in measurements. Furthermore, several improvements were carried out within the scope of the Test Site using the expertise of all participants and the infrastructure of the Test Site. The developments, reports and results obtained are both significant and helpful for manufacturers, road authorities, practitioners, research and consultancy.
The German Federal Ministry of Economics and Technology is funding a projectrncalled "Leistra2" with the aim of understanding the tire road contact and to find measures to reduce traffic noise, in particular to reduce the noise of tires rolling on pavements, i.e. tire-road noise. The project is composed out of three mayor subjects, low noise tires, low noise pavements and verification of the results, each made out of single sub-projects. The purpose of this paper is to give a survey about Leistra2 and to report about the latest activities and results. More detailed information and contact data of the partners involved can be found at http://www. LeiStra2.de. The program is the successor of the program LeiStra (Leiser Strassenverkehr), dealing with similar topics.rn