The Tromsø Bridge in northern Norway has a separate walkway on one side and a cycle path on the other. The purpose is to reduce conflicts between pedestrians, cyclists and electric scooter users. Nevertheless, many pedestrians choose the wrong side of the bridge, which can have major consequences if an accident occurs.
For Troms County Council, this raised an interesting question: Can signs projected directly onto the ground contribute to better traffic safety?
Tested on over 28,000 road users
To find the answer, the county municipality had SINTEF – one of Europe’s largest research institutes – conduct a study on the bridge in the spring of 2026.
Claudia Moscoso, research manager at SINTEF.
“We combined camera observations with a survey among road users. All told, over 56,000 registrations were collected before the dataset was quality assured and reduced to 28 432 relevant crossings in the direction of Tromsø city centre,” says SINTEF researcher Claudia Moscoso.
Several different sign variants were tested. The first scenario served as a reference, and consisted only of the current signage. The other three variants included LED projections on the ground with different combinations of symbols and text.
One of the alternatives used well-known blue symbols for pedestrians and cyclists, while the others included variations, such as the text “Walk here” and a pedestrian-prohibited sign.
Half of the pedestrians made the wrong choice
“One of the most striking findings was how big the problem actually is,” says Moscoso.
The study showed that 50.1 percent of all registered pedestrians walked in the bike lane. At the same time, only 1.5 percent of cyclists rode on the pedestrian path. So it was primarily pedestrians who chose the wrong lane.
One of the most striking findings was how big the problem actually is.
“We also found that the problem is greater on weekends. The probability of choosing the right side of the bridge is around 40 percent lower than on normal weekdays,” says Moscoso.
LED projected signs made a difference
All three LED solutions improved road users’ choices compared to the current signage alone. But one solution clearly stood out.
The scenario that used blue projected symbols for both pedestrians and cyclists had the strongest effect. Here, road users had a 210 percent higher probability of choosing the right path than with today’s physical signage.
The proportion of people who actually chose correctly increased from 61.5 percent in the reference scenario to 83.4 percent with the best LED solution.
LED signage not an alternative on its own
The findings point to a clear area of application for the technology. Although LED signs work well, their role is primarily to support existing traffic regulations.
“This provides an important premise for further use: LED projection should not be understood as an alternative to official traffic signs, but as a means of understanding the existing signage,” says senior advisor Solveig Sandnes at Troms County Council.
Why do these signs work?
The explanation seems to be that LED signs catch people’s attention exactly where the decision is made.
“Traditional traffic signs are on poles next to the route, whereas LED signs are projected directly onto the ground in front of the road user. This way, you are presented with the information at the moment you have to choose between a pedestrian and a bicycle path,” says Moscoso.
In addition, the survey showed that road users prefer symbols they are already familiar with. Signs that resembled established traffic signs were considered both more visible and easier to understand than solutions based on text or prohibition symbols.
Most visible around dusk
Since the signs are projected onto the ground, they are not covered by large amounts of snow like traditional signs can be. There are limitations, however. People experienced the signs as easiest to see at dusk. Bright daylight made the projections more difficult to see. Younger road users also reported better visibility than older ones.
Although almost 70 percent of the registrants stated that they easily understood the meaning of the signs, the results show that design and contrast are still crucial for their effectiveness.
Can the technology be used in more places?
The researchers believe the results are promising, but at the same time point to an important question: How should this type of “horizontal traffic sign” be regulated?
Moscoso points out that today’s regulations are designed for vertical road signs. “If horizontal (projected) signs are to be used, it may be necessary to clarify how they should be standardized and what legal status they should have.”
A small measure with a big impact
Although the technology alone cannot solve everything, the results show that familiar symbols on the ground can make it easier to orient oneself and contribute to increased traffic safety.
“For a city that is receiving more visitors each year, a luminous symbol on the ground could prove to be just the reminder needed to get people to choose the right path,” says Moscoso.
Reference:
Claudia Moscoso, Shubham Jain & Trond Foss: LED-lys projiserte trafikkskilt og deres effekt på fotgjengernes adferd [LED-light projected traffic signs and their effect on pedestrian behaviour].
