Bakgrund

Pedestrians are among vulnerable road users. According to the reports from Trafikverket, Swedish Transport Administration, the number of severely injured pedestrians in the road transport system often are understated since the statistics are excluding those who are falling on the ground¹. The same report suggests that the number of those injuries does not decrease in recent years despite the decreasing trend in other traffic-related injuries. From a different perspective, costs of fall-related injuries are relatively comparable to the costs of the road traffic accidents, according to the reports from the Swedish Civil Contingencies Agency (MSB)². These facts indicate the importance of exploring and preventing fall-related injuries in pedestrians, and particularly among the elderly. Adults older than 65 years old are at more considerable risk of fall-induced injuries due to their physical frailty^3,4. Contrary to the burden of research in traffic accidents, fall-related injuries have received less attention concerning the resources and researches⁴. There are several solutions to prevent fall-induced injuries ranging from wearable kits to newly developed, soft asphalt for sidewalks. Among those preventive solutions, the soft asphalt seems to demonstrate better competence, since it could reduce the risk of injury not only for the elderly but also for other vulnerable road users. The ultimate objective of this study is to examine the essential competence of the produced soft asphalt specimens in preventing fall-induced hip fractures.

Metod

We will examine the hypothesis that decreasing the stiffness of the asphalt can potentially decrease the risk of hip fracture in the elderly. Regarding this hypothesis, several produced soft asphalt specimens are tested to evaluate the mechanical properties. A relevant mechanical model is thereafter employed to describe the behavior of specimens during the falling incident. Ultimately, the specimen's material properties are implemented in a finite element model of a pedestrian to simulate falling incidents. We properly position the finite element model of the pedestrian, similar to known falling postures prior to impact.

Resultat och slutsats

The preliminary study on the rubber composite material typically used in playgrounds⁵ indicates that reducing the stiffness of this material to 5 times lower than the common value can decrease the maximum force on the femur up to 25 percent. Further simulations are necessary to assess the competence of the soft asphalt specimens.

1. The Swedish Transport Administration. Analysis of Road Safety Trends 2017. (The Swedish Transport Administration, 2018).

2. Swedish Civil Contingencies Agency (MSB). Social Costs of Accidents in Sweden. 1–29 (2012).

3. Ceccato, V. & Willems, O. Temporal and spatial dynamics of falls among older pedestrians in Sweden. Appl. Geogr. 103, 122–133 (2019).

4. Naumann, R. B., Dellinger, A. M., Haileyesus, T. & Ryan, G. W. Older adult pedestrian injuries in the United States: causes and contributing circumstances. Int. J. Inj. Contr. Saf. Promot. 18, 65–73 (2011).

5. Li, X. & Kleiven, S. Improved safety standards are needed to better protect younger children at playgrounds. Sci. Rep. 8, 1–12 (2018).

Bakgrund

Snö och is är bidragande orsak till halkolyckor för fotgängare och cyklister. För att säkerställa beredskap, frekvens och kvalitet när trafikantflöden ökar samtlidigt som klimatet blir nyckfullare kan självkörande fordon vara en väg framåt.

Metod

Ett nyutvecklat fordon har framtagits, redo för automation. I demonstrationer ska fordonet utföra ett arbete (exempelvis snöröjning eller sopning) och samtidigt undvika kollisioner med trafikanter och objekt. Operatörernas arbetsmiljö och infrastrukturens påverkan är viktiga fokusområden.

Resultat och slutsats

Ett nyutvecklat fordon har framtagits, redo för automation. Demonstrationer genomförs på AstaZero. Operatörernas behov av interaktion med fordonet har undersökts.