The difference between Transport allowance and Conveyance allowance are:
Transport allowance:
Travelling allowance is given to meet commuting expenses between place of residence and office or to meet personal expenditure of employee of transport business.
It is fully taxable.
Conveyance allowance:
Conveyance allowance is allowance granted to meet the expenditure on conveyance in performance of office duty.
It is exempt up to the conveyance amount actually incurred.