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.



International Conference on Electric Road Systems starts today

Electric Road Systems (ERS) is a relatively new concept with many initiatives on the way. To learn from each other and stimulate new collaborations the Swedish Research and Innovation Platform for Electric Roads arranged the first international conference...


Same survey of road users’ attitudes in 50 countries

At the Road Safety on Five Continents Conference, RS5C, one entire session presented a large survey of road users' attitudes in 38 countries. Results show large differences between countries in many areas, both regarding behavior and attitudes. A new survey...


Good results with alcohol interlock program according to Swedish study

An alcohol interlock program makes it possible for drink driving offenders to continue their everyday lives. In a Swedish study most of the participants were satisfied with the program and experienced improved health. They also reported drinking alcohol more...


Traffic safety in the spotlight

Today the Conference Road Safety on Five Continents (RS5C) opened in Jeju Island, South Korea. More than 220 participators have come from all over the world to present findings and learn about traffic safety. Dr. Young Tae Kim, Secretary-General of the...


VTI will develop simulators for ambulance staff

VTI has initiated a pilot study for paramedics with the Centre for Teaching & Research in Disaster Medicine and Traumatology and Linköping University. The aim is to give ambulance staff the opportunity to practice critical medical tasks in a moving vehicle in...


Unique electrified road opens in Sweden

The world’s first electrified road recharging the batteries of cars and trucks while driving opened in Sweden. The Swedish Minister for Infrastructure, Tomas Eneroth, was at the formal inauguration of the electrified road on April 11, 2018. VTI is one of 22...