autistic daughter has been limited to wheelchair

My daughter got her autistic diagnosis at the age of 3, she still has no communication and severe sensory overloads. going outside is a big trigger for her sensory issues and she will just drop to the floor and bang her head or hit her face when having a meltdown in the street. The whole experience is traumatising for us both as she looks in pain with the noise, smells, lights etc. Whenever we go outside she refuses to walk or runs away onto roads and traffic, she is now too big for any special pushchairs. As she gets older & bigger its harder to restrain her or calm her down when she's being aggressive, which sadly happens a lot due to her frustration when we don't know what she's saying or wanting. Occupational therapy and the hospital have provided her with a wheelchair,we have used it a few times now and she seems to be a lot less anxious when she's outside in the chair (we also use ear defenders when outside which helps ) I was wanting to know if any other mothers/carers have had to use a wheelchair due to their child's severe meltdowns / autism related symptoms. I feel like we get stared at when outside or looked at when my daughters seen getting in and out of the chair because she is physically able to walk and isn't paralysed I feel like maybe other people think she doesn't need the chair and I don't want people to stop and ask me what's wrong with her or question me which seems to be the case . please any reply's on this subject would be a big help.