Do Pictograms Improve Bicycle Safety? Lessons from Cologne
Context and background
In 2025/26, the City of Köln introduced bicycle pictogram chains, shared-lane markings painted onto the road surface to improve bicycle safety, on three pilot streets. These markings indicate that cyclists are permitted to use the full carriageway and that drivers must give way. While the markings cost-effectively expand cycling infrastructure without physical separation, their effectiveness hinges on whether road users actually notice them and understand their meaning.
The Odenthaler Straße in Köln Dünnwald, one of the three pilot streets, runs through a suburban, densely car-oriented neighbourhood in the north-east of Köln. The cities traffic management department partnered with CDK to evaluate the rollout.
Continues below the photo: Odenthaler Straße in Köln-Dünnwald, one of the three pilot streets for bicycle pictogram chains.
© Köln Stadt
What were the objectives of this project?
The City of Köln and CDK co-designed a survey to answer three core research questions:
1. Do residents notice the new pictograms on the road?
2. Do they correctly understand the markings’ legal meaning?
3. Do the markings contribute to a sense of safety, whether for a cyclist sharing the lane or as a driver approaching one?
A secondary aim was to reach a broad cross-section of road users in-situ, including people who might not typically engage with cycling policy, including pedestrians, public transport users, and drivers. We wanted to gather data with enough granularity to support the cities decisions on whether and how to expand the pictogram programme to more streets.
Continues below the map: Location of the two Dialog Boxes on Odenthaler Straße, Köln-Dünnwald.
How was the impact on bicycle safety evaluated?
From planning to installation, the project ran from January to May. The survey was co-designed with the municipality, using questions structured around the three research goals. A branching logic ensured that cyclists received tailored follow-up questions about their safety experience, while drivers were asked separately about any behaviour changes.
Two CDK Dialog Boxes were installed at Odenthaler Straße for five consecutive weeks (15 April – 21 May). The first was placed outside the ORLEN petrol station on the northern side of the street; the second at the Odenthaler Kiosk near the Dünnwald station on the southern side. Both sites sit directly in the corridor where the pictogram chains are painted, ensuring that respondents were answering about markings they had just encountered.
Continues below the photo: The Dialog Box at Odenthaler Kiosk, near Bahnhof Dünnwald, the higher-footfall of both locations.
Engagement overview
Over five weeks with two Dialog Boxes, the deployment reached a genuinely diverse cross-section of the local community. The respondent profile reflected all major transport modes: 35% primarily use public transport, 27% drive, 26% cycle, and 8% travel mainly on foot. Sixty-two percent use Odenthaler Straße daily or several times a week, meaning the data captures people with direct, repeated experience of the markings.
The 61% completion rate stands out for a suburban public-space deployment with a 14-question survey. In our experience, completion rates for this type of deployment typically hover around 40–50%. This suggests that road safety is a topic residents care enough about to see through a fairly detailed questionnaire.
The two locations performed very differently: Display 2 at the kiosk near the train station attracted 382 responses compared to 127 at Display 1 by the petrol station. The difference can largely be explained by dwell time, people waiting for a train or stopping at the kiosk had a natural moment to engage. Peak engagement typically occurred in the mornings and afternoons, consistent with commuter rhythms at a well-connected suburban street node.
Continues below the photo.
What were the insights from the deployment about bicycle safety?
Awareness: more than half of all participants had noticed the pictograms
Among all 509 people who started the survey, 51% had already noticed the pictogram chains. 35% said they spotted them immediately; a further 16% said they had noticed them recently. For a marking rolled out just weeks before in a suburban context without accompanying media coverage or signage, this is a reasonably solid baseline. Cyclists and frequent users of the street were more likely to have noticed than occasional visitors or drivers.
The flip side is that 49% had not noticed the markings at all, despite many using the street regularly. This points to a need for complementary communication, such as signage, social media, or local outreach, to close the awareness gap.
Continues below the charts: awareness of the bicycle pictogram chains among respondents (n=509).
Understanding: the meaning remains unclear to many
Knowing that the markings exist is not the same as knowing what they mean. In a quiz question, respondents were asked what road users must do when they see the pictograms. Only 46% gave the correct answer: that cyclists are permitted to use the full carriageway. Eleven percent mistook the marking for a 25 km/h speed limit, and 17% could not answer the question at all.
Younger respondents (under 30) and regular public transport users scored best on the quiz. Car drivers were among those least likely to answer correctly, a notable finding given that their behaviour is the one most directly affected by the markings’ intent.
Interestingly, those who reported following cycling and transport news regularly scored highest (59% correct), while those who described the topic as “very important to them” scored lowest (39% correct), suggesting that personal engagement with the issue does not guarantee familiarity with specific road markings.
Continues below the charts: quiz question on the meaning of the bicycle pictogram chains (n=365).
Safety impact: positive signals, particularly for cyclists
When asked whether the pictograms helped create a safer environment, 52% of respondents gave a positive rating (“somewhat helpful” or “very helpful”). Scepticism was concentrated among car drivers and older respondents, while cyclists and pedestrians were more positive.
Among cyclists specifically, the group, for which the markings are designed for, 56% reported an improved sense of safety. For 12% it feels “somewhat safer” and a further 12% “much safer.” This is a meaningful finding, echoing the results of a 2021 study by Koppers et al. across 15 German municipalities, which found a statistically significant improvement in perceived safety for cyclists after pictogram chain installation. Our data from Dünnwald points in the same direction.
Among cyclists specifically, the group, for which the markings are designed for, 56% reported an improved sense of safety. 12% felt “somewhat safer” and a further 12% “much safer.” This is a meaningful finding, echoing the results of a 2021 study by Koppers et al. across 15 German municipalities, which found a statistically significant improvement in perceived safety for cyclists after pictogram chain installation. Our data from Dünnwald points in the same direction.
Continues below the charts of perceived safety contribution of the pictogram chains (n=336).
Continues below the charts of change in safety feeling among cyclists after pictogram installation (n=57).
Behaviour change among drivers: an interesting tension
44% of car drivers reported some form of behavioural change: 18% said they pay more attention to cyclists, 12% say they drive more slowly, and 14% report both. The majority (53%) reported no change at all. This aligns with a tension reported by Koppers et al. who found via video analysis that drivers do overtake less frequently and with greater lateral distance after pictogram installation, yet many of those same drivers may not consciously register a change in their own behaviour. In other words, the pictograms may be nudging drivers in ways that operate below the threshold of self-awareness.
Conclusions
This research illustrates both the potential and the limits of road markings as a standalone intervention. In a suburban context, where cycling infrastructure is sparse, car use is higher, and the daily audience for the markings is less cycling-oriented than in an inner-city setting, the pictogram chains generated a solid response: over 500 interactions, a 61% completion rate, and positive safety signals from more than half of all cyclists surveyed.
The clearest takeaway, however, is the knowledge gap. With fewer than half of respondents correctly identifying what the markings mean, the pictograms are working at a fraction of their potential. The findings give the City of Köln a concrete, evidence-based case for pairing the physical markings with a targeted communication campaign.
Reflections on using CDK for bicycle safety evaluations
The CDK deployment also demonstrated that it is possible to reach a genuine cross-section of a suburban community on a mobility topic, not just the cycling advocates, but the drivers, the transit users, and the pedestrians whose attitudes and behaviour shape how safe the road feels for everyone.
