The city of Salzburg has published the results of its real-world laboratory on Nußdorferstraße: the tested road markings measurably increase the distance at which motor vehicles overtake cyclists. In particular, wide, multi-purpose lanes improve road safety.

More distance thanks to clear markings

In the second half of 2025, two types of road marking were trialled in the real-world laboratory on Nußdorferstraße to improve safety for cyclists. Test riders on the research bicycle by Salzburg Research have proven effective: drivers are keeping a greater distance when overtaking and many cyclists report feeling safer.

Two sections with different markings were examined:

• Wide multi-purpose lanes two meters wide and narrow central lanes three meters wide.
• Large bicycle pictograms with so-called sharrows.

The measurement trips took place in two phases: one in June and one in September and October 2025. Following feedback from the first phase, additional signs were installed to indicate the correct way to overtake.

356 overtaking maneuvers analyzed scientifically

A total of 356 overtaking maneuvers were recorded and evaluated. In the second phase, the median overtaking distance was as follows:

• 1.12 meters in the section with wide multi-purpose lanes and a narrow central roadway
• 1.05 meters in the section with large wheel pictograms and sharrows

This increased the distance in both variants. However, when overtaking at speeds of over 30 km/h, the legally prescribed minimum distance of 1.5 meters is still not achieved.

The analysis also shows that oncoming traffic affects overtaking behavior. On a positive note, some drivers can be seen to delay overtaking until it is safe to do so. Additionally, the introduction of the 30 km/h speed limit in the real-world laboratory contributes to improving road safety.

Wide multi-purpose strips particularly effective

These findings are also confirmed by feedback from the public. A total of 442 people took part in the consultation. Sixty percent of cyclists said they felt safer on wide multi-purpose lanes, while 53 percent said they felt safer with large bicycle pictograms and sharrows.

Scientific analysis shows that clear markings increase awareness and can contribute to greater overtaking distances. Based on this, the city of Salzburg plans to identify suitable locations within the urban area where these measures can be implemented in cases where structural solutions are not possible.

Both options are sensible, but the wide multi-purpose lanes are more effective. It is therefore recommended that these lanes be implemented throughout Nußdorferstraße in the future and that other suitable locations in the city be examined.

The real-world laboratory was set up by zukunftswege.at the mobility laboratory in collaboration with Salzburg Research Forschungsgesellschaft and Con. Sens Mobilitätsdesign, acting on behalf of the City and State of Salzburg.

More information:

• Press release from the City of Salzburg on the results: stadt-salzburg.at
• Information about the real-world laboratory zukunftswege.at: zukunftswege.at/teststrecke
• Report on the application of the new markings: Reallabor für sicheres Radfahren in Salzburg: neue Markierungen
• Report on test rides with the research bicycle: Forschungsfahrrad überprüft Wirkung von neuen Bodenmarkierungen

How close and how dangerous are overtaking maneuvers between motor vehicles and cyclists, actually? Under the leadership of Salzburg Research, researchers from Germany, Austria, and Switzerland investigated over 7,000 overtaking maneuvers using state-of-the-art measurement technologies. The results were used to develop concrete recommendations for the safe and comfortable management of cycling traffic.

Road cross sections are often not wide enough to accommodate structurally separated bicycle facilities that meet the guidelines. In the absence of suitable alternative routes, these road sections usually remain gaps in the cycling network. Conflicts that affect road safety accumulate on these sections, in both urban and rural areas.

In a transnational research project led by Salzburg Research, empirical studies and state-of-the-art measurement technologies were used to develop concrete recommendations on how to make cycling on main roads safer and more comfortable under constricted conditions. Using Open Bike Sensors, stationary and mobile laser systems (LiDAR — Light Detection and Ranging) and camera-based analysis, comprehensive data on the traffic situation and its effects on cyclists were collected for the first time. The results show: “A ‘clearer infrastructure language’ and/or restrictive legal measures are needed on roads with narrow conditions in order to guarantee the desired minimum overtaking distance,” says Sven Leitinger, head of the transnational study at Salzburg Research.

Innovative measurement methods for evaluating overtaking processes

A crucial parameter for the safety and comfort of cyclists is the distance that motor vehicles keep when overtaking. In urban areas, an overtaking distance of 1.5 meters is considered safe — this is also the minimum legal overtaking distance in Germany and Austria. Therefore, a special focus of the research project was to objectively determine the actual overtaking distances in numerous field studies.

A variety of data collection and analysis methods were used in the field studies: Open Bike Sensors, stationary and mobile LiDAR sensors, video observations, human sensory measurements, and interviews. In particular, the use of LiDAR sensor technology in the form of a research bicycle was a new and innovative measurement approach that allowed the complete overtaking process to be recorded objectively for the first time.

In total, more than 7,000 overtaking maneuvers by cyclists were analyzed on 22 test routes in Germany, Austria, and Switzerland.

Results of the field studies: Overtaking distances are too small

The extensive field tests clearly showed that conventional cycling infrastructure or mixed motor vehicle and bicycle traffic without cycling infrastructure does not lead to the desired overtaking behavior in constricted spaces. Despite a wide variety of characteristics, the median overtaking distance was between 1.0 and 1.3 meters on almost all test routes, which is below the minimum overtaking distance of 1.5 meters required in Austria and Germany.

During the test rides with the research bicycle, the distances and speeds between the motor vehicle and the bicycle were also recorded at different times — when approaching, reversing, and overtaking. Particularly on the busier test routes, motor vehicles were more likely to tailgate, cyclists were more likely to overtake, and it was more dangerous to reverse in front of cyclists.

Recommended solutions for more safety at bottlenecks

A key solution is to take appropriate measures to ensure that motor vehicles overtake cyclists at a sufficient distance or do not overtake at all.

For road widths between 6.5 and 9.5 meters, the introduction of wide cycle lanes and narrower core lanes at 30 km/h is recommended to optimize overtaking distances. For even narrower sections, the researchers suggest qualified mixed traffic with a maximum speed limit of 30 km/h and additional markings — pictogram chains/sharrows — to increase the visibility of cyclists. In addition, specific recommendations on legal aspects in Germany, Austria, and Switzerland were developed, as well as proposals for asymmetric cycle guidance, for narrow sections, on single lanes, and for participatory processes to involve relevant stakeholders, in order to promote evidence-based decisions on cycle guidance.

The recommendations for action form an important basis for practical implementation in cities and communities in the D-A-CH region. The aim is to close existing gaps in the network, make cycling safer and more attractive, and make transport as a whole more climate-friendly.

Background information on the RADBEST research project

The RADBEST project was carried out by multidisciplinary and multinational consortium: Salzburg Research Forschungsgesellschaft mbH (AT), University of Salzburg, Department of Geoinformatics (AT), Steinbeis Transferzentren GmbH at Karlsruhe University of Applied Sciences, Prof. Eckart, Chair of Transport Ecology (DE), University of Applied Sciences of Eastern Switzerland, Competence Center for Pedestrian and Bicycle Traffic, Prof. Hagedorn (CH), con.sens mobilitätsdesign (AT) and KFV – Kuratorium für Verkehrssicherheit (AT).

RADBEST is an R&D service commissioned by the Austrian Federal Ministry for Climate Protection (BMK), the German Federal Ministry for Digital Affairs and Transport (BMDV) and the Swiss Federal Roads Authority (ASTRA) under the program management of the Austrian Research Promotion Agency (FFG).

Networking and automation of vehicles offer a great opportunity to also increase the safety of cyclists. Salzburg Research, together with the Bike2CAV consortium, has for the first time validated wireless communication channels between different vehicles, bicycles and the infrastructure under real conditions, tested a method for cooperative detection of collision risks and developed warning concepts for cyclists.

Road accidents involving bicycles have been steadily increasing for years. In 2015, the road accident statistics of Statistics Austria recorded 6,901 road accidents with bicycles, in 2021 it was already 9,578. The number of cyclists killed in this period fluctuated from 32 to 50 people per year. The accidents with other vehicles involved mostly occurred in a turning situation in an intersection, with the bicycle predominantly going straight ahead.

“In addition, there are a large number of near-accidents that do not appear in any accident statistics. That’s why we wanted to make these risks easier to assess with our research work, so that measures can be taken even before something happens,” says project manager Cornelia Zankl from Salzburg Research.

Technology helps reduce collision risks

The latest technological developments in the field of vehicle communication by means of ITS-G5, bicycle localisation, environment perception of the connected and automated vehicle by means of cameras and LiDAR sensors as well as roadside sensors with cameras created the basis for cooperative solution approaches for the detection and avoidance of collision risks. Vulnerable road users such as cyclists should not only be detected, but actively involved in collision avoidance.

This brings added value on several levels: Cyclists are warned of collisions at an early stage in order to recognise dangerous situations and avoid accidents. Networked vehicles and driver assistance systems can detect cyclists more reliably through improved detection quality as well as active communication and can react at an early stage. Municipalities and infrastructure operators receive objective assessments of risk zones at traffic intersections and can mitigate them preventively through targeted measures.

Real-life testing in the city and in the countryside

In the research project, different solution approaches were analysed in order to be able to select suitable and safe methods. The most promising methods were tested in a controlled experiment and tried out in three scenarios at two test intersections in rural and urban areas.

The experiments at the test intersections Weiserstraße/Gabelsbergerstraße in the city of Salzburg and at the B158 in the Salzburg municipality of Koppl, which were equipped with smart sensor technology, involved the use of a networked, automated vehicle as well as a novel networked research bicycle. A continuous chain of different data processing methods was tested, from the self-localisation and detection of road users, through the detection of collision risks and the generation and transmission of warning messages, to communication with cyclists and other road users.

Central research results

The Bike2CAV research project has impressively demonstrated the high complexity of the technical implementation of cooperative systems, as a large number of system components have to interact in a coordinated manner. The following central results were achieved in the defined focus areas of the project:

• Risk zones for cyclists at traffic junctions:
  The researchers succeeded in a semi-automated derivation of interaction zones in intersection areas based on statistical accident probabilities. An important finding was that cyclists often use the infrastructure at the studied urban intersection differently than intended. This is probably due to the fact that the planning primarily follows the needs of motor vehicle traffic.
• Smart bikes and self-localisation from the cyclist’s point of view:
  Highly accurate self-localisation of cyclists is central to reliable detection of collision risks. In addition to two GNSS receivers installed in the Holoscene Bike, the accuracy of a smartphone and that of a helmet-mounted high-precision sensor were also investigated. The goal was a deviation of less than 50 cm with 99.9 percent reliability. Especially in an urban environment, the targeted localisation accuracy was very challenging due to dense development and a railway subway. A lateral deviation of 0.5 metres at 95 per cent reliability in a rural environment and less than two metres lateral deviation at 95 per cent reliability in an urban environment were achieved.
• V2X communication for bicycles:
  The approach of equipping bicycles with V2X technology in order to enable automated vehicles to perform active recognition via ITS-G5 in addition to passive recognition via environmental sensors has proven to be effective. Such bicycles are not yet available on the market, but a proof-of-concept prototype could be tested in the project.
• Detection of cyclists by the infrastructure and V2X communication
  Using extensive sensor technology, cyclists are to be visually detected and tracked by the infrastructure. The camera-based AI detection system used to recognise and classify motor vehicles and pedestrians was extended and optimised to recognise cyclists.
• Detection of cyclists by vehicles:
  Based on machine learning methods, an intention recognition of cyclists was implemented, thus enabling a better path prediction and determination of collision risks. Especially the visual determination of body posture and hand signal recognition are important for reliable movement prediction.
• Warning concepts for cyclists:
  The requirements for non-deflective warnings of collision risks between a vehicle and cyclists were identified in a co-creation process with lead users. Different warning modes – acoustic, visual and tactile – were designed and tested using a navigation app on the smartphone, vibration on the handlebars and acoustic signals in the helmet. Cyclists found auditory warnings particularly helpful, especially in situations where a vehicle is approaching from behind.
• Real-life testing:
  In all six scenarios tested, risky situations with collision risk could be simulated and collision warnings generated. The field test succeeded in generating a good selection of typical high-risk situations for cyclists.

Details and background information on the technologies used: Weniger Kollisionen mit Radfahrenden durch kooperative intelligente Verkehrssysteme (press release in German)

Cycling is an important component for achieving national and European climate goals. This is why Germany, Austria and Switzerland are pushing for the rapid expansion of the cycle path network. In cramped road conditions, however, safe cycling guidance becomes a challenge. A transnational consortium under the leadership of Salzburg Research is investigating not only objective safety but also the subjective perception of safety and is developing evidence-based recommendations.

In cramped road conditions, especially in critical cross-sections with lane widths of only six to 8.5 metres, conflicts and incidents with the various road users increase. Overtaking manoeuvres with little distance, so-called “dooring” accidents with parked vehicles, but also conflicts with pedestrians when cyclists swerve into the side space are inevitable.

Although the regulations in the DACH region contain recommendations for the guidance of cyclists on such stretches of road, they are handled very differently. New solution options such as overtaking bans, protective lanes, bicycle pictogram chains or encounter zones are being discussed and partly also applied. A transnational consortium is now developing evidence-based recommendations for cycling guidance, especially in confined road conditions, as well as technically sound considerations between different alternative solutions.

Investigated for the first time: objective and subjective safety

For the first time, a comparative empirical data basis on objective safety as well as on the subjective perception of safety for representative stretches of road and different cycling routes is created in this research work.

Both mobile and stationary sensor technologies – ultrasound, LIDAR and video – are used to measure objective safety. In addition, in all three DACH countries, the subjective perception of safety is also surveyed by means of interviews and sensor technology for stress measurement.

RADBEST is a commissioned R&D service of the Austrian Federal Ministry for Climate Protection (BMK), the German Federal Ministry of Digital Affairs and Transport (BMDV) and the Swiss Federal Roads Office (ASTRA) under the programme management of the Austrian Research Promotion Agency mbH (FFG).

For more information see press release (in German): Mehr Sicherheit für Radfahrende in beengten Straßenverhältnissen