Federal Highway Research Institute

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Highway design, traffic flow, traffic control

Safety and possible applications of "protected intersections" (RV.0001)
Cycling is currently experiencing a high level of dynamism. Due to global networking, ideas from abroad are increasingly being taken up and their use is also being demanded in Germany. So far, however, there is a lack of reliable findings on the safety assessment of such proposals, on the basis of which a practical use in municipalities could be recommended. In this context, "protected intersections" are being considered as a new possibility for safe and at the same time comfortable intersection design for cyclists. However, some elements of the "protected intersection" are also discussed critically. Overall, there is a lack of scientific knowledge on the effect of "protected intersections" and uniformly applicable recommendations. The aim of this project is therefore to provide basic knowledge in this area. Specifically, "protected intersections" are to be investigated with regard to objective and subjective safety, traffic behaviour and the attractiveness for the different types of traffic.

Partially automated recording and evaluation of safety-relevant road parameters - Feasibility study for a proactive safety assessment (03.0580)
Within the framework of the CEDR (Conference of European Directors of Roads) Call 2013 Safety, the project ESReT (European Safety Review Tool) was carried out. The aim was to develop an application that allows road parameters to be recorded, evaluated and ultimately design features to be calculated in a simple and cost-effective manner. With this data, the developed web-based "ESReT tool" should then check whether the specific requirements of the 4 funding countries for certain design parameters are met or if there are infrastructure related deficits. The aim of the present research project is to evaluate the ESReT tool with regard to national requirements in order to form the basis for further development towards a national application. The extent to which the adaptation of the app used within the framework of ESReT for the visualisation and documentation of the road network could also provide a benefit with regard to visual inspection is also to be evaluated. At the same time, alternative further recording options are to be identified and evaluated with regard to their suitability for recording the relevant features. Both tools together (detection plus processing and evaluation) should enable the evaluation of the most important road infrastructure deficits for roads outside urban areas. This would mean an enormous gain in efficiency in the assessment of routes with regard to a safe road design.

Safety investigation of turbo roundabouts in Germany (02.0397)
Turbo roundabouts are multi-lane roundabouts in sections, where lane changes on the circular carriageway are to be avoided and lane overlaps in the circular exits are to be prevented by pre-sorting in the circular approaches and placing new lanes on the inside of the circular carriageway. Turbo roundabouts were developed in the Netherlands and have proven themselves there in about 250 applications. In Germany, there is currently experience with about a dozen turbo roundabouts. In 2015, the FGSV published a working paper on turbo roundabouts that is intended to contribute to the appropriate design of turbo roundabouts. At the same time, various roundabouts were built that showed deficits in terms of compliance with the German Road Traffic Regulations (StVO) as well as in terms of traffic routing and road safety. Therefore, the effects of different designs on road safety are to be investigated and evaluated at several realised turbo roundabouts. In addition to an accident analysis, behavioural observations and conflict analyses are to be carried out at turbo roundabouts already in operation. In this way, findings on the use and acceptance of the traffic facility by different user groups (in particular private motor vehicles, cyclists and pedestrians) can be obtained in addition to the accident analysis carried out.

Implementation of the amendment to EU Directive 2008/96/EC (6119009)
With the EU Directive 2008/96/EC on road infrastructure safety management, the EU wants to come closer to its transport policy goals of significantly reducing the number of road accident victims and the severity of the consequences of accidents. Ten years after the directive came into force, it was evaluated on behalf of the EU Commission. This resulted in a proposal by the EU Commission for a revision of the 2008 Directive, which was first negotiated as part of an EU legislative consultation procedure and finally published on 26.11.2019 as Directive (EU) 2019/1936. The amendments entered into force on 16.12.2019 and must now be transposed into national law within 2 years. On behalf of the Federal Ministry of Transport and Digital Infrastructure, the BASt is accompanying the implementation of the amendment of Directive 2008/96/EC into German law. The main task is the development of a suitable procedure for a network-wide road safety assessment according to article 5 of the amendment directive.

Optimisation of behaviour, regulation and structural situation in crossing situations between cycling and motorised traffic (70.0964)
High-quality and high-performance connections for cyclists are increasingly being used in Germany. Corresponding projects, such as cycle expressways or cycle priority routes, have already been completed or are in concrete planning. In addition, there are numerous independently routed cycle connections, for example on former railway lines, which offer comparable travel speeds and comfort or have high cycling traffic volumes. However, at junctions of such connections with the rest of the network, inconsistent structural designs and traffic regulations can often be observed, which leads to confusion and uncertainty among road users. The aim of this research project is to derive recommendations under which constellations and conditions which type of design and regulation of corresponding junctions should be provided in order to promote a high level of acceptance.

Safe speeds on one-lane rural roads (02.0443)
The aim of the project is to develop a procedure, considering automated driving, with the help of which a "safe" speed recommendation can be given for single-lane rural roads depending on design features. This speed recommendation is intended to produce a driving behaviour appropriate to the connecting function of the road. As an introduction, considerations should be made as to which speeds are considered "safer" under which boundary conditions. Harmonisation of speed behaviour should also be included here, as this is shown to be beneficial in terms of road safety and with regard to automated driving. In addition to sectoral considerations from Germany, international approaches should also be taken into account, in which, for example, the cross-section and road environment and the overtaking regime are also included. The procedure to be developed should be applicable in particular to existing roads. The practicability of the application is to be demonstrated for selected road network sections. Finally, recommendations will be derived on how the speed variables can be practically determined and used to improve road safety on the rural road network.

The Infrastructure Safety Improvement Potential (ISVP) - A suitable road safety performance indicator for road infrastructure? (82.0752)
In addition to the established accident and casualty figures the Safety Performance Indicators (SPI) are expected to improve the detection of changes in the level of safety of the transport system. One main factor influencing road safety is infrastructure. During the development of the 2019 Safety Research Programme of the Federal Highway Research Institute a potential indicator has already been identified for this purpose in an attempt to quantify the extent of infrastructural deficits. The ‘Infrastructure Safety Improvement Potential (ISVP)’ describes the deviations from the design of a network element (basic segment or junction) that is optimized solely on the basis of safety considerations and thus quantifies the infrastructural safety deficits of a road infrastructure facility. While the ISVP theoretically already provides an SPI for the road infrastructure, the primary aim of the project is to clarify which survey design can be used to determine a meaningful ISVP. Since an extensive and costly survey of the infrastructural and traffic-related boundary conditions as well as segmentation of the road network into individual road infrastructure elements is required, a network-wide and also complete recording of all possible deficits cannot be carried out at an appropriate cost. Open questions therefore exist, especially with regard to a meaningful sample or the question of which infrastructural characteristics or deficits should be considered in the determination of the ISVP. In the context of the project, once the questions regarding the survey design have been clarified, an ISVP is to be determined on a pilot basis for a (outside urban areas) sample network in order to be able to prove its practicability.

Reverse parking trucks at rest facilities - A contribution to more efficient land use? (02.0435)
The continuing increase in freight traffic as well as the regulation on driving times and rest periods lead to a considerable demand for truck parking facilities along motorways during the night hours. In order to meet the high parking demand at rest facilities, further measures are necessary in addition to new construction, conversion and expansion projects. The aim of this project is to clarify whether reverse parking of trucks at rest facilities on motorways is a suitable measure to use the existing or newly constructed parking areas in a more space-saving way or to offer truck parking facilities where space availability is limited. Thus, when trucks park in reverse, additional driving lanes that are necessary for conventional parking areas to exit the parking zone can be saved and the free space can be used for other purposes. In order to obtain findings on traffic feasibility and suitable design parameters, accident analyses, behavior and conflict observations as well as investigations on traffic flow and space saving potential will be carried out on existing as well as pilot rest facilities. As a result, recommendations for the reverse parking of trucks at rest facilities are to be developed, which can be used for an update of the "Recommendations for Rest Facilities on Roads" (ERS).

International "Safety Review Tools" - How can the available international findings be used or made usable for Germany?! (03.0607)
Nationally and internationally, efforts are being made to improve road safety work and to support those involved and responsible by means of innovative tools with respect to identify, justify and implement efficient, but also effective road safety measures. The number of such tools has grown to a considerable number in the international arena. In Germany, however, these tools and results receive little attention. The reasons for this are, on the one hand, a lack of awareness and language barriers. On the other hand, the lack of transferability of international findings to German road design features or traffic conditions is seen as an obstacle. The aim of the research project is to review the international tools, to describe them for national experts and to evaluate them with regard to national transferability (federal, state or municipal level). The aim is to analyse target groups of international users and to identify and document potential users in Germany and their current tools. In addition, the tools and databases are to be evaluated in particular with regard to the potential and possibilities of national application. At the end specific recommendations for the implementation should be provided and open questions or the challenges need to be addressed should be highlighted. What has to be done that the potential of the international tools for the road safety work in Germany can be exploit?

Procedures for the analysis of bottlenecks and deficiencies in the major urban street network (77.0516)
The quality of traffic flow in cities is influenced by the design of the street network, traffic regulation/management and traffic demand. In many cities, high traffic demand during rush hour leads to congestion at intersections. The result of the congestion are time losses and stop & go traffic, which leads to increased emissions. The task of the project is to develop a procedure that identifies bottlenecks in the network and the causes of deficiencies using generally accessible, commercial travel time data. The deficiencies are to be assessed by the approaches of the "Guidelines for Integrated Network Design" (RIN) (2008) and the "German Highway Capacity Manual" (HBS) (2015). Due to the increasing availability of Floating Car Data (FCD), alternative possibilities for assessing the quality of service and for bottleneck analyses in urban street networks arise. The aim of the project is to demonstrate how the FCD data source can be used for congestion analysis. The results should enable a more efficient and practical way of verifying the achievability targets according to the RIN and offer a supplement to the procedures for network segments described to date in the HBS.

Effects of the use of type 1 longer trucks (18.0027)
In the German field trial with longer trucks (2012-2016) the number of type 1 longer trucks (extended articulated vehicles) was very small. Therefore, not all questions could be answered for this type by the end of the five-year field trial. In the framework of the present project, the questions still open concerning the use of type 1 longer trucks are now to be addressed: Assessment of the market potential for type 1 longer trucks and subsequent effects on traffic demand, road infrastructure restrictions, possible effects on road load as well as on safety equipment of road tunnels.

Recommendations for application of truck overtaking prohibitions on German motorways (03.0577)
The Road Traffic Regulations generally allow traffic restrictions only in case of a particular local danger. Since 2009 the order of truck overtaking prohibitions on motorways is facilitated if a severely disrupted traffic flow can be expected to affect traffic safety. The aim of the present project is to examine whether changed boundary conditions and new findings lead to a new assessment of the recommendations on prohibition orders. To this end, empirical investigations of traffic flow and simulation studies as well as an economic evaluation of the effects on traffic flow are to be used to derive criteria and recommendations applicable nationwide for the situational arrangement of truck overtaking prohibitions on motorways, including their spatial extension, which go beyond the consideration of accident conspicuities.

Effect of lane boundaries at motorway entries on driving behaviour and traffic safety (02.0433)
In the research project, already implemented solutions of lane boundaries (no passing (solid center line)/no passing in one direction) in the area of motorway entries are to be examined with regard to their effect on driving behaviour, traffic safety and traffic flow. It is also foreseen to find out with which intention the measure was implemented at the respective areas. As a result, recommendations should be derived as to under which infrastructural and traffic-related conditions and with which accompanying traffic regulations (speed limit, ban on truck overtaking) these types of marking in the area of motorway entries have a positive effect on traffic safety and traffic flow. In addition to the entrie area itself, the effects of the measure should also be analysed at the beginning of the lane boundary. The developed recommendations serve to update the guidelines for the design of motorways (RAA) and the guidelines for the marking of roads (RMS) in the sense of traffic safety and infrastructure with a sufficient traffic flow.

Major weaving segments between junctions on motorways (03.0561)
The aim of the investigation is the development and calibration of an analytical design framework for major weaving segments between closely spaced motorway junctions to be included in the German Highway Capacity Manual (HBS). Furthermore, the suitability of the macroscopic software tool "German FREEVAL", which was developed on behalf of BASt, is to be tested. Based on the knowledge gained on the traffic flow, recommendations for the lane configuration and marking of major weaving segments in combination with signposting are to be developed on the basis of a traffic safety analysis. These are to be prepared for inclusion in the Guidelines for the Design of Motorways (RAA) and the relevant regulations for marking and signage (RMS and RWBA).

Technical and legal framework for advertising on rest facilities and service stations (SV.0014)
The Accounting and Audit Committee of the German Bundestag requested the Federal Government to investigate whether and how the traffic areas of rest facilities and service stations on federal highways and the parking spaces for carpooling can be used for advertising measures - without impairing traffic safety. In particular, drivers must not be disturbed or distracted from the safe performance of their driving task in any case - for example by impairing visibility, glare, distraction or impaired orientation. The functional operability and recreational function of the rest facilities must also be taken into account. Within the framework of the project, a feasibility study with basic technical and legal aspects is to be carried out.

Procedure for determining the decisive traffic demand for the planning and design of roads (01.0203)
The task of design in the context of new construction, reconstruction and expansion of roads is to prove that the traffic demand expected on a road system can be met and with what quality. With the introduction of the Handbook for the Design of Road Traffic Facilities (HBS), a standardisation of the traffic demand on which the procedures are based was also carried out in such a way that the traffic intensity of the nth most heavily loaded hour was defined as the design traffic intensity. The new procedure results in higher requirements for the availability, quality and evaluation of traffic data. The aim of this project is to compare and evaluate different approaches for estimating the traffic demand of the nth hour or for determining a traffic demand that is considered to be decisive for the design.

Updating the calculation methods for the capacity of roundabouts (02.0425)
The aim of the project is to update the existing calculation methods for the capacity of roundabouts and to answer open questions. The current methods are based on knowledge from several research projects from the early 1990s. In the meantime, roundabouts have gained considerable importance in traffic planning. Their number in Germany is estimated at around 15,000 and further new roundabouts are regularly planned. Among other things, the effects of pedestrians and cyclists on the performance of the roundabout access roads and the significance of the traffic leaving the roundabout for the capacity of the neighbouring access road are to be investigated. When weighing up the different basic forms of a junction, its capacity is the decisive criterion. By specifying and updating the knowledge in this field, wrong decisions in the planning of junctions should be avoided.

Barrier-free design of crossings at cross-town links of federal highways (02.0406)
Ensuring mobility and the equal participation of all people in society as part of services of general interest is a major challenge of demographic change. In view of the increasing importance of pedestrian traffic in old age and the consideration of the needs of people with sensory or physical disabilities, barrier-free traffic space design is of great relevance for socially desirable, independent mobility. Within the framework of the project, a uniform crossing point in the form of a ramp in combination with ground indicators is to be investigated and incorporated into the technical regulations as a standard construction method. In addition, different forms of crossing facilities implemented in practice will be analysed and evaluated. The aim is to determine the operating conditions of the different crossing facilities according to specific local characteristics. As a result, an overview is to be provided to clarify when which type of installation is to be used. In addition to the special design of the crossing installations, visual contrasts play a decisive role for people with visual impairments in order to be able to move independently in public spaces. Solutions that have already been implemented are to be considered so that it will be possible to update the technical regulations.

proFUND (6117001)
The need for expansion and renewal of the German motorway network will require numerous workzones to be set up in the future. Providing comprehensive information to road users regarding current and future workzones is therefore extremely important. The “Workzone -Information-System” of the Federal government and Federal states already takes this approach, but until now does not have an uniform, quality assured data basis yet. The objective of the project is to investigate the scope and topicality of previous workzone reports. Road users will be given an opportunity to evaluate the workzones they have driven through, which will firstly allow an appraisal of the workzone reports and secondly an assessment of the perceived quality of the workzones from the drivers point of view. By comparing the workzone reports with the user feedback, Federal states will be able to adapt their information management more specifically to the needs of users in the future. Furthermore, the combination of statistical surveys (Floating Car Data) and field tests should identify and classify workzone characteristics that have a significant negative influence on traffic flow and user awareness. The aim is to collect information on these characteristics and deduce best practice approaches that might provide a lasting improvement to the design of future workzones.

Aspects for the temporary use of hard shoulders on motorways (02.0367)
Hard shoulders are extremely important for traffic flow and traffic safety and are therefore an indispensable component of motorways. Only in exceptional cases do the guidelines for building motorways provide for hard shoulders to be temporarily deployed for other uses. One such case, for example, is when the existing traffic volumes repeatedly exceed the capacity limit of the section of motorway, resulting in congestion or serious traffic disruptions. The objective of the research work is to collate significant aspects on the temporary use of hard shoulders, and to derive recommendations from these for their planning, design and where applicable operation on motorways in order for future practical application according to uniform standards to be safe, efficient and economical. This also includes systems for temporary use of hard shoulders in conjunction with traffic management systems and with complex entry and exit types.

HBS-compliant simulation of traffic flow on single carriageway rural roads (02.0418)
With the introduction of Guidelines for the Design of Rural Roads (RAL), it is expected that overtaking lanes will be increasingly planned either continuously or in sections in the area of federal trunk roads. This measure is believed to increase road safety in overtaking situations significantly. Corresponding procedures for these two cross-section types have also been added in the 2015 edition of the German Highway Capacity Manual (HBS). In practice, however, only very few roads with three-lane sections exist yet. Planners of these overtaking sections currently have a high degree of freedom regarding the position and length of theses sections, so that the use of simulation tools is an ideal way of optimising not only construction costs but also the traffic flow for the given route parameters. The objective of this project is to screen available simulation tools in regarding their suitability for simulating traffic flow on single carriageway roads with and without overtaking lanes, including overtaking manoeuvres towards oncoming traffic. Based on this, standard parameter combinations have to be determined, which guarantee a high compliance of the simulation results with the dimensioning recommendations of the HBS.

Future challenges for the design of inner-city roads (70.0926)
The aim of the study is to provide foundations for the design of inner-city roads with a view to achieving sustainable mobility. For this purpose, the future challenges resulting from the altering forms of mobility and in particular from increasing multimodality are to be developed for the inner-city road system under different peripheral conditions (for example, design situations), analysed individually and the effects on recommended cross-sections and design elements presented. Current examples in practical use are to be analysed and the comments and remarks of users of the guidelines considered. The results of the research project are to be incorporated directly in the update of the Guidelines on the Construction of Urban Roads (RASt).

Operating criteria and design information for rural T-junctions and intersections (02.0373)
One of the main problems concerning the safety of rural roads is the design of junctions. Despite recent research conducted into rural road crossings, questions remain about the operating criteria for traffic lights and triangular traffic islands. The objective of the research project is to offer planners of rural roads concrete recommendations for operating and designing T-junctions and intersections along single carriageway, two lane country roads. The limits of use to be derived from an economic point of view should enable sensible planning of rural T-junctions and intersections with different operating and draft design arrangements, not merely when planning new roads but also for use in the existing road network.

Monitoring the effectiveness of milled rumble strips (6111025)
Studies suggest that approximately one third of fatal accidents on federal motorways are due to fatigue and inattention. However, there are a high number of unreported cases, as the frequently insufficient evidence does not allow for drawing the conclusion that fatigue and inattention were the cause of accident. One way to prevent traffic accidents due to fatigue or inattention are milled rumble strips in the shoulders. Within the framework of the study "Safety effect of milled rumble strips along the BAB A24" it could be shown that the percentage of accidents due to a coming off the side of the road to the right was reduced by 43% due to milled rumble strips. Based on this positive result, recommendations for uses were developed and suitable road sections were determined in Germany for milling of rumble strips. The specified road section are now to be tested to determine whether the positive result on the BAB A 24 can also be achieved with different boundary conditions.