Reimbursement Of Petrol Expenses

Dear All,
I work for a research company where lot of staff are entitle for re-imbursment of conveyance on the basis of Kms run. Looking into the frequent changes in the petrol prices, we need to revise reimbursement rates too. My request to all of you to share some formula/basis how to work out the correct re-imbursment rate/km for two wheeler and four wheelers.
Thanks
Hemant

Hi,
In Our Company we are paing 2.75/- per Km for 2 wheelers and 5/- Rs for 4 wheelers. excluding their Lunch fare. Based on your policies finalise it..\
Mahesh

We are fixed some reimbersments including the salary (i.e. Petrol, Telephone, Entertainment and Driver salary.) end of the year who submitt the bills they will get the tax exemption up to the max limit fixed in salary.