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Guardrail damages and maintenance experiences on narrow roads with a median barrier - A follow-up study

Kapeiden keskikaideteiden kaidevauriot ja kunnossapidon kokemukset

For this follow-up study data was gathered and analyzed on all the guardrail damages that had occurred by the autumn of 2003 on roads that have overtaking lane sections equipped with median barriers and on narrow four-lane roads with a median barrier. The studied roads were main road 4 between Kempele and Haaransilta (2+2 lanes), main road 5 between Vehmasmäki and Hiltulanlahti (2+2 lanes), main road 6 between Muukko and Ahvenlampi (2+2 lanes), main road 9 between Orivesi and Muurame (2+1 and 2+2 lane overtaking sections) and trunk road 54 between Loppi and Launonen (2+1 lane overtaking sections). Altogether about 45 km of road sections with a median barrier were monitored, and guardrail damages on these sections were recorded since the road sections were taken into use. A total of 23 incidents of guardrail damage occurred on the road sections. The average rate of damage to the median barriers was 0.46 incidents/km of median barrier/yr. The average rate of damage per traffic volume was 0.16 incidents/million vehicle km. The damage frequency (number of incidents of guardrail damage per length of median barrier) was lower on 2+1 lane sections than on 2+2 lane sections, but the risk of damage (number of incidents of damage per traffic volume) on both was of the same magnitude. The calculated damage frequency and the risk of damage is greater on the 2+2 sections of highway 9 than they are on the other road sections. Nevertheless, the number of incidents of damage is so small that it is not possible to draw final conclusions about the effects of the cross-section type and other properties of the road. The risk of damage to median barriers appears to be significantly smaller in Finland than in Sweden. However, here also the quantity of material is too small to be able to make a reliable comparison. All the accidents that occurred on the road sections with a median barrier and were reported to the police from 1.10.2003 to 30.9.2004 were studied. There were 44 accidents. Slightly over one third (36%) of the accidents that occured on the road sections resulted in median barrier damage. Most of the median barrier accidents occurred during overtaking situations. Because in such situations the median barrier has prevented the driver from entering the oncoming lane, median barriers have decisively reduced the risk of serious accidents. Some of the median barrier accidents also occurred as a result of avoiding vehicles that were stopped because of an accident or other reasons. The reason for some of the accidents could not be decided on the basis of the accident description. According to the accident register data, median barrier accidents did not result in personal injury. The cost of repairing guardrail damage, including materials and labor, varied from a few hundred euros to 25,000 euros. The cost of repairs is roughly 1,000 euros/km of median barrier/yr. This cost of damage includes the renewal of a few guardrails and guardrail posts (typical damage). Traffic signs affixed to the median barrier have caused some problems. The signs should be placed high enough so that the mirrors of trucks and especially snowplows do not reach the signs. The use of normal-sized lane signs instead of large signs has also helped the situation. A wider 2.0 meter median also provides a little more space than a minimum-width 1.7 meter median. Crashworthy guardrail terminals are used on motorways and other busy roads. Ramping the end of the median barrier into the ground appears to be an adequate solution on roads with lower traffic volume. Long sections of road with a median barrier require an openable section of median barrier every 2-3 km. The location of these sections should be marked with reflectors that are visible in the dark, and the guardrail should be easily and quickly openable. When a section of road with a median barrier is taken into use it is important to inform the rescue organization, the police and the maintenance organization where the openable sections are located and how they can be opened. Alternate route and traffic control plans should also be compiled for all road sections with a median barrier in case of an abnormal situation. This report may be found at http://alk.tiehallinto.fi/julkaisut/pdf/3200920-vkeskikaideseuranta.pdf

Language

  • Finnish

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Filing Info

  • Accession Number: 01015464
  • Record Type: Publication
  • Source Agency: TRL
  • ISBN: 951-803-455-9
  • Files: ITRD
  • Created Date: Jan 12 2006 9:07AM