Conveyance allowance is to meet the expenditure on conveyance in performance of duties of office. Amount exempt from IT: amount of allowance or amount utilized,whichver is lower.
Transport allowance is for commuting between residence and office. Amount exempt: Rs.1600 pm
Repairs & maintenance not included in conveyance allowance. However, if fuel and maintenance bills (for car) are submitted, then it is regarded as perquisite and amount is exempt as per limits for different scenarios.