INTRODUCTION: Children with impaired mobility often experience negative impact on overall development leading to depression, social isolation, and perceived lower quality of life. OBJECTIVE: Our study explored the effects of Power Mobility Devices (PMD), in the form of modified ride-on toy cars with two distinct activation/steering technologies, on functional independent and social function in young children with severe multiple developmental impairments. METHODOLOGY: Twelve children (age range 12-54 months) with neuromuscular, musculoskeletal, and genetic diagnoses, and metabolic progressive diseases participated. Significant cognitive, visual, or communication impairment was not exclusionary. Two types of activation and steering modifications (proportional control joystick and line follower technologies) were provided. Paired samples FINDINGS: Improvements were observed in all three subscales for Functional Skills (significant 9.8% increase in self-care, 21.4% in mobility, and 17.5% social/cognitive) and Caregiver Assistance (significant 35.4% increase in self-care). CONCLUSION: These quantitative results support findings of previous studies analyzing qualitative data, suggesting that early power mobility interventions provide positive improvements in the quality of life of children with severe developmental disabilities.