A median cross-over collision occurred this morning on Highway 401 just west of Merlin Road, west of Chatham, Ontario. An eastbound truck passed through the new High Tension Cable Median Barrier (HTCMB) and struck two other westbound trucks just west of the Merlin Road overpass. Early reports indicate there were no serious injuries. However the extent of damage visible on the trucks suggests this was more due to luck than engineering design.
Views of the damaged cable barrier suggests its interaction with the striking vehicle was not ideal. The photo below shows that only four posts of the barrier were collapsed and then only 3 or 4 more were slightly displaced.
Typical longitudinal barriers gain their strength from their length. Thus while the cable and its posts may be displaced in the area of direct contact we should expect to see additional deformation in the anchor posts on both sides of the area of direct contact. Such induced damage is indicative that the barrier absorbed additional energy beyond the zone of direct contact. What is visible in the above photo is a lack of damage to the anchor posts beyond the immediate zone of contact. This suggests that not much energy was dissipated by the barrier system. The fact that the cables are still intact means that the truck either had to pass under or over those cables. Submarining under the cables in not likely given the height of the truck. Therefore it suggests the truck rode over top of the cables.
Overall, this incident does provide confidence that the new HTCMB will perform adequately in terms of preventing the cross-over of heavy trucks. While it may turn out to be an isolated and unusual incident there is no way of knowing for sure until further experience is obtained with the barrier’s performance. Ontario’s Ministry of Transportation officials have supported the safety of the barrier based on previous studies. However concern has to be expressed with the result of the present collision.
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