Exempt people on Attendance Allowance from vehicle tax

The system needs to be fairer and not ageist. The Government discriminating against the elderly. The vast majority of affordable adapted mobility cars are in a higher tax bracket, this is due to the size of vehicle and subsequent engine size. Many elderly disabled people simply don't have the choice to have a smaller care. I want to Government to ensure that people on Attendance Allowance are exempted from vehicle tax, the same as it is for those who receive other disability benefits.