The dynamics of electric powered wheelchair sideways tips and falls: experimental and computational analysis of impact forces and injury

Table 2 Multinomial logit regression showing curb height and approach angle significantly affect the risk of tip

	Multinomial logit estimates^a			Change in predicted probability (belted)^b			Change in predicted probability (unbelted)^b
Independent variables	Fall vs Upright	Tip vs Upright	Fall vs Tip	Fall	Tip	Upright	Fall	Tip	Upright
Speed (m/s)	−7.96 (4.74)	−0.20 (2.82)	−7.76 (5.38)	0	−0.004	0.013	−0.075	0.075	0.000
Curb Height (m)	84.55** (38.03)	90.83** (38.01)	−6.29 (36.48)	0	0.999	−0.999	0.001	0.896	−0.897
Approach Angle (°)	0.03 (0.25)	−0.89** (0.32)	0.92*** (0.31)	0	−1.00	1.00	0.818	−1.00	0.182
Belted	−17.13** (6.89)	−4.48 (3.67)	−12.66* (6.69)

Curb height and restraint use are the most significant factors in falls. Driving speed did not affect tip or fall risk. ^aThe values are multinomial logit parameters, standard errors are in brackets. ^bChange in predicted probability, a positive value means the event is more likely to occur as the parameter value increases, a negative value means the event is more likely to occur as the parameter value decreases (*p = 0.058, **p < 0.05, ***p < 0.005)

ISSN: 1743-0003