Report on a road traffic accident involving a passenger car and a central barrier on the E6 at Andelva in Eidsvoll municipality on 16 July 2021
Road traffic report 2023/01
The accident on 16 July 2021 occured when a passenger car with two occupants crashed into the central barrier, at an emergency/maintenance crossing point where one of the locks was in the open or unsecured position. The central barrier came apart and penetrated into and through the passenger car, and the passenger suffered serious injuries. The investigation has shown that active corrosion of the central barrier, which was made from weathering steel, caused incorrect operation of the relevant lock at the emergency/maintenance crossing point during maintenance and reduced the strength of the barrier. In the NSIA’s opinion, weathering steel is not a suitable material for road safety equipment in damp and salty road environments where the material will corrode. The investigation has also identified a number of shortcomings relating to the NPRA's procurement, approval, execution and follow-up of the pilot project for weathering steel on the E6 road between Dal and Boksrud.
The central barrier penetrated into and through the passenger car. Photo: The police
The section of the E6 road between Dal and Boksrud is about 11 km in length. It was built between 2009 and 2011, and the motorway was opened for traffic in November 2011. The speed limit was raised from 100 km/h to 110 km/h in 2015.
This section of road was part of the Norwegian Public Roads Administration’s (NPRA) development of the E6 road between Gardermoen Airport and Kolomoen, and it was part of a pilot project in which weathering steel was used in road safety equipment. Aesthetics and design were among the criteria that formed the basis for the choice of material, supplier and crash barrier design.
Mesta’s maintenance personnel charged with lubricating the emergency/maintenance crossing points had not received training or sufficient instruction in how the lock design worked and how to deal with stiff locks caused by corrosion. The design of the lock at the emergency/maintenance crossing point had shortcomings that meant that the lock could appear to be locked without this being the case, in a manner that it was difficult or impossible to detect through visual inspection in connection with maintenance.
Since the road was salted during the winter, the central barrier was in a damp and salty environment. The design of the barrier also contributed to the build-up of water and salt. This accelerated the active corrosion of the weathering steel and prevented the material from forming a protective layer of corrosion as intended.
The investigation has also identified a number of shortcomings relating to the NPRA’s procurement, approval, execution and follow-up of the pilot project for weathering steel:
• The weathering steel barrier was purchased and installed on parts of the section of road without approval from the Directorate of Public Roads having been applied for or received.
• No documentation of the material’s suitability for road safety equipment in the road environment in question was obtained before the central barrier was installed and approved.
• The Directorate of Public Roads approved the pilot project for a section of road with a length of as much as 110 km and a planned speed limit of 100 km/h.
• The NPRA did not draw up an inspection programme to follow up the pilot project on weathering steel, which was a prerequisite for the Directorate of Public Roads' approval.
• The Directorate of Public Roads did not follow up with the road owner to make sure that an inspection programme was actually prepared and implemented.
• It was a pilot project, but the maintenance contract did not specify that the barrier was made from weathering steel that needed special follow-up and non-conformity reporting or that the emergency/maintenance crossing point lock design was untested.
• When the NPRA became aware that the weathering steel did not form an outer layer of rust to prevent further corrosion, no measures were implemented to ensure that the barrier retained its strength.
• The locks on the emergency/maintenance crossing points were designed specifically for the pilot project, and the design had not been used before. The emergency/maintenance crossing points had not been crash tested, nor had computer simulations been carried out.
The Norwegian Safety Investigation Authority submits four safety recommendations following the investigation.
Published 18.04.2023
Safety recommendation
Safety recommendation Road No 2023/01T
The passenger suffered serious injuries in the run-off-the-road accident on the E6 road at Andelva in Eidsvoll municipality on 16 July 2021 as a result of a central barrier made of weathering steel splitting at an emergency/maintenance crossing point and penetrating the passenger car because one of the locks was in the open or unsecured position. The investigation has shown that active corrosion weakened the emergency/maintenance crossing points and reduced the strength of the barrier. In the NSIA’s opinion, weathering steel is not a suitable material for road safety equipment in damp and salty road environments where the material will corrode.
The Norwegian Safety Investigation Authority recommends that the Norwegian Public Roads Administration replace the weathering steel barriers with galvanised barriers on the E6 road between Dal and Kolomoen. The barrier’s residual strength, as a function of critical sheet thickness based on active corrosion, must be followed up until the barriers on the section of road have been replaced.
Safety recommendation Road No 2023/02T
The passenger suffered serious injuries in the run-off-the-road accident on the E6 road at Andelva in Eidsvoll municipality on 16 July 2021 as a result of a central barrier made of weathering steel splitting at an emergency/maintenance crossing point and penetrating the passenger car because one of the locks was in the open or unsecured position. The investigation has shown that the design of the locks used in the emergency/maintenance crossing points in the central barrier had weaknesses that affected the locks’ function and could result in locks appearing to be locked when they were not. The emergency/maintenance crossing points in the new galvanised steel barrier whose installation on the Dal–Kolomoen section of the E6 road began in 2022 use the same lock design as the original solution, but in galvanised material.
The Norwegian Safety Investigation Authority recommends that the Norwegian Public Roads Administration either replace the locking mechanisms or ensure that the locking mechanisms installed at the emergency/maintenance crossing points in the central barrier on the E6 road between Dal and Kolomoen work and are used and locked as intended. This also means that the emergency/maintenance crossing points must meet the requirements stipulated in the Norwegian Public Roads Administration’s manual N101E Vehicle Restraint Systems and Roadside Areas (2021).
Safety recommendation ROAD No 2023/03T
The passenger suffered serious injuries in the run-off-the-road accident on the E6 road at Andelva in Eidsvoll municipality on 16 July 2021 as a result of a central barrier made of weathering steel splitting at an emergency/maintenance crossing point and penetrating the passenger car because one of the locks was in the open or unsecured position. The investigation has shown that the Directorate of Public Roads’ approval of the pilot project was conditional on an inspection programme being drawn up in cooperation between the Norwegian Public Roads Administration’s Eastern Region and the Directorate of Public Roads’ bridge section, but no such programme was drawn up. Also, the Directorate of Public Roads did not follow up with the road owner to make sure that an inspection programme was actually prepared and implemented. The Directorate of Public Roads’ approval also stipulated a requirement for the weathering material to have the same service life as galvanised steel, but the supplier was nevertheless not required to document the crash barrier’s service life.
The Norwegian Safety Investigation Authority recommends that the Norwegian Public Roads Administration ensure in its processing of new materials and designs that documentation of conditions stipulated in the approval and measures to be implemented is submitted before approval is granted.
Safety recommendation Road No 2023/04T
The passenger suffered serious injuries in the run-off-the-road accident on the E6 road at Andelva in Eidsvoll municipality on 16 July 2021 as a result of a central barrier made of weathering steel splitting at an emergency/maintenance crossing point and penetrating the passenger car because one of the locks was in the open or unsecured position. The investigation has shown that no documentation was obtained of the weathering steel’s suitability for road safety equipment in the road environment in question before the central barrier was installed and approved. The Directorate of Public Roads nevertheless approved the pilot project for a section of road with a length of as much as 110 km and a speed limit of 100 km/h. The Norwegian Safety Investigation Authority is of the opinion that when testing new materials and designs, the Norwegian Public Roads Administration must ensure that traffic safety is addressed in terms of both the applicable speed limit and the length of the section of road in question.
The Norwegian Safety Investigation Authority recommends that the Norwegian Public Roads Administration put in place procedures for approval of projects that deviate from the road design norms to ensure that testing of new materials and designs is conducted on a limited scale until their suitability has been documented and traffic safety considerations addressed.
Facts
| Location | E6, north of brigde over Andelva, Eidsvoll in Viken |
| Occurrence date | 16.07.2021 |
| Accident type | Other accident |
| Road class | European road |
| County | Viken |
| Vehicle type | Passenger car |
| Type of Transportation | Private transport |
| Accident category | Annen ulykke |