Bedömd vägojämnhet på vägar med låga IRI-värden

Sven Dahlstedt

The reported investigation is one part of a project concerning methods for measurement of the longitudinal roughness of roads and the necessary accuracy. In this study the main focus was on the subjective experience of roughness on roads with low IRI-values, i.e. fairly good roads. Using the available roughness data it was also studied how much a random error, added to the IRI-values, would influence the calculated correlations with the subjective estimates. The investigation was carried out as a magnitude estimation experiment, in which some 20 observers made their estimates while travelling as passengers first in a car, and later in a lorry.

The main results of the study were as follows:

- Subjective roughness seems to be a linear function of roughness according to IRI within the studied roughness range.

- The reliability of the observers, and the agreement between them, seems better in the car than in the lorry.

- For the very smooth sections (IRI almost =0) the roughness experienced in the lorry might have been caused by other vibration sources than the road surface.

- For some road sections with a "non-typical" spectral composition of the road roughness it was found that the correlation between IRI and subjective roughness decreased considerably.

- Some observers had even stronger correlations between their subjective ratings and road profile expressed in RMS units than between their estimates and IRI roughness.

- The simulations of random errors added to the IRI-values showed that, within the studied range and with the fairly large number of observations (45), random measurement errors up to at least ± 0,2 IRI-units can be considered insignificant.



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...