Självförklarande gator: samband mellan faktisk hastighet, hastighetsgräns och trafikmiljö


The aim of this study was to improve the understanding of the concept of self-explaining roads in urban areas by studying the relationship between speeds at a particular location, the speed limit and the road environment. The relationship between actual speed levels, speed limit and traffic environment has been studied based on earlier speed measurements in 23 different cities and a total of 69 measuring points. In addition, traffic engineers from 73 different municipalities studied photos from 20 different locations and made an assessment of the speed limit at the site, so-called blind estimation.

The results show that when the relationship between the speed levels and a number of site-specific background variables was studied, the actual speed levels were explained not only by road-specific variables such as speed limits, traffic flow and road type, but also variables that describe the surrounding environment such as type of area (inner city, residential areas, outside city areas) and presence of vulnerable road users. Blind-estimates of speed limits show that it is difficult to estimate a speed limit only by looking at a photo. Roads with speed limit 70 km/h were most easy to estimate (67% hit-rate) and roads with speed limit 60 km/h were most difficult (35% hit-rate). A logistic regression showed that lane width was the most important factor when predicting the speed limit by only looking at a photo.

The results showed that the probability of a correct estimate of the speed limit increases the narrower the road gets. In conclusion, the concept of self-explaining roads in urban areas is very difficult with the existing speed limits it is not a reality today from a national perspective. It is far from easy for the road users to assess the present speed limit by only looking at the road and traffic environment if they for some reason failed to notice the speed limit sign.



Open seminar with Mistra SAMS international scientific advisory...

Mistra SAMS international scientific advisory panel (ISAP) is visiting Stockholm, and the program will host an open seminar where the panel members will give talks in their area of expertise.

ERPUG 2017

The five year anniversary of  European Road Profile Users' Group (ERPUG) Forum will take place at Ramboll head quarter, Copenhagen, Denmark October 19-20, 2017. 



Vehicle Driver Monitoring: sleepiness and cognitive load

To prevent road crashes it is important to understand driver related contributing factors, which have been suggested to be the critical reason in 94 per cent of crashes. The overall aim of the project Vehicle Driver Monitoring has been to advance the...


Tomas Svensson new director-general

Tomas Svensson was today appointed Director-General of VTI. Tomas has been acting Director-General since January 2017. 


Crash testing bicycles at VTI

For the first time single bicycle crashes have been simulated at the VTI crash safety laboratory.


A case study exploring firefighters’ and municipal officials’ preparedness for electrical vehicles

A VTI-study presents a social perspective on new vehicle technology. It explores the self-reported preparedness of the fire departments (i.e., rescue services) in Sweden’s three largest cities regarding rescue operations involving electrical vehicles (EVs).


Pioneering research on and about bicycles at VTI

Under what circumstances might cyclists lose tyre grip? What actions could then be taken to prevent a crash? VTI is currently developing a theoretical model of the behaviour of bicycle tyres during braking and steering in different situations and on different...


Virtual pedestrians create efficient stations

If more people are to choose sustainable travel, then the public transport stations of the future must be designed so that pedestrians can get where they are going quickly, without congestion or queues. The Swedish Road and Transport Research Institute (VTI)...