Safe System Snippet: Barriers and kerbs Kerbs play an important role in road/street design, however their proximity to roadside barriers can create challenges. When kerbs are placed near barriers, they can alter the way vehicles interact with barriers, increasing the risk of underride, override, and vehicle instability. Additionally, kerbed roadsides with soil backfill can lead to increased stiffness in the system and higher rail loads, which may cause rail ruptures. Drainage features can also interfere with post placement, leading to the need for post omission. In 2021 Midwest Roadside Safety Facility evaluated the performance of the Midwest Guardrail System (MGS) when placed near a kerb and with an omitted post. The results from crash test, in which a 2270T pickup truck impacted the system at 100 km/h and at a 25-degree angle, were good. The vehicle was successfully contained and redirected without any rail tearing or instability. The system met all safety performance criteria as outlined in MASH test 3-11. (Barrier was 150mm behind kerb). 📽 Video credit: Midwest Roadside Safety Facility ———— Sign up to our mailing list for more snippets and news: https://lnkd.in/gXsAeAa9 #roadsafety #trafficsafety #SafeSystemSnippet
Even W beam barriers throw a vehicle back into the traffic lane. Something that has been rejected by the authorities.
Really important issue! We considered this aspect when I worked on building the alignment for crash barriers in Bogotá-Colombia in 2019, and later for the National Guideline (2022), taking into account U.S. research and references.
Two observations: 1. The far-side wheels lifted up, posing a potential risk of the car flipping over. Designing a slope-shaped barrier could help the near-side wheels climb the barrier, counterbalancing the rotational angular momentum. This climbing action would also dissipate kinematic energy. 2. A car with a lower chassis may get stuck in the gap between the ground and the lower end of the barrier, potentially causing fatal damage.
So NO problem with kerbs used to enhance effectiveness of barriers. There is a place for the barriers but across South Australia and the Adelaide hills they are over installed and create new hazards, particularly trapping kangaroos, wombats and other wildlife they are horrible. There are not enough breaks and animals get trapped before being obliterated by cars. Then it is not safe to render assistance to injured wildlife. I end up hating the dam things
Whilst I see benefits with rigid and flexible, the benefits are only good when operable. Wire rope given its popularity is now less likely to be repaired or maintained and needs to be considered in application..
Instead of sending a car back on the traffic and killing somebody, find a way to arrest the vehicle with a net.
I remember discussing this with you Kenn back in 2014 when I was drafting a crash barrier guidelines collecting loads of information and preparing a training course for my client's understanding of the various types of crash barriers for various purposes and locations to be applied. Is there design criteria for kerb placement along guard rails or other crash barrier type that you could share ??
I’d like to see the same video with those wire barriers. Seems Main Roads here in WA can't keep up with the repair, bits of barrier with broken wires and bent over posts would be lethal. Some of the barriers down are alonside railway tracks and the take months to get fixed.
K RAIL
Fellow | BioInnovate Ireland
2moThis is very interesting analysis by MwRSF. However, how often are kerbs used on roads where a 25-degree impact is attainable at 100km/h? A shallower impact angle might present some very surprising vehicle behaviour, especially where the barrier height has been installed relative to lip of kerb.