A method to model anticipatory postural control in driver braking events

Human body models (HBMs) for vehicle occupant simulations have recently been extended with active muscles and postural control strategies. Feedback control has been used to model occupant responses to autonomous braking interventions. However, driver postural responses during driver initiated braking differ greatly from autonomous braking. In the present study, an anticipatory postural response was hypothesized, modelled in a whole-body HBM with feedback controlled muscles, and validated using existing volunteer data. The anticipatory response was modelled as a time dependent change in the reference value for the feedback controllers, which generates correcting moments to counteract the braking deceleration. The results showed that, in 11 m/s2 driver braking simulations, including the anticipatory postural response reduced the peak forward displacement of the head by 100 mm, of the shoulder by 30 mm, while the peak head flexion rotation was reduced by 18°. The HBM kinematic response was within a one standard deviation corridor of corresponding test data from volunteers performing maximum braking. It was concluded that the hypothesized anticipatory responses can be modelled by changing the reference positions of the individual joint feedback controllers that regulate muscle activation levels. The addition of anticipatory postural control muscle activations appears to explain the difference in occupant kinematics between driver and autonomous braking. This method of modelling postural reactions can be applied to the simulation of other driver voluntary actions, such as emergency avoidance by steering.Biomechanical EngineeringMechanical, Maritime and Materials Engineerin

Cumulative Exposure to Disadvantage and the Intergenerational Transmission of Neighbourhood Effects (discussion paper)

Studies of neighbourhood effects typically investigate the instantaneous effect of point-in-time measures of neighbourhood poverty on individual outcomes. It has been suggested that it is not solely the current neighbourhood, but also the neighbourhood history of an individual that is important in determining an individual’s outcomes. The effect of long-term exposure to poverty neighbourhoods on adults has largely been ignored in the empirical literature, partly due to a lack of suitable data. Using a population of parental home-leavers in Stockholm, Sweden, this study is innovative in investigating the effects of two temporal dimensions of exposure to neighbourhood environments on personal income later in life: the parental neighbourhood at the time of leaving the home and the cumulative exposure to poverty neighbourhoods in the subsequent 17 years. Using unique longitudinal Swedish register data and bespoke individual neighbourhoods, we are the first to employ a hybrid model, which combines both random and fixed effects approaches, in a study of neighbourhood effects. We find independent and non-trivial effects on income of the parental neighbourhood and cumulative exposure to poverty concentration neighbourhoods. The intergenerational transmission and exposure effects suggest the need for a more dynamic formulation of the neighbourhood effects hypothesis which explicitly takes temporal dimensions into account.OTB Research Institute for the Built Environmen