Independent mobility is believed to be essential for perceptual-motor, cognition, language and social skill development. It is important to increase the independent mobility in children with disabilities and further enhance their development, especially motor and socialization. Assistive and power mobility devices allow children with disabilities to move independently within their environment and may increase the opportunities to explore and interact with people and environment . However, issues to consider before prescribing an assistive device include factors such as age, accessibly to community environments, cost, social acceptance of the device and the adaptability of the device to growth. This study is to use the customized, modified ride-on toy cars, to enhance the independent mobility, exploration and socialization through low-cost, family-centered approach. It will also improve family's understanding of children's capabilities, which improve their development. Investigators will recruit 60 children with who are between 1 to 3 years old and diagnosed as motor delay (>1.5 sd). They will be randomly assigned to one of the following two groups: hospital-based program group and regular therapy group.