I get pd .42/km for business travel, is there anything that I can claim as an expense?

RCA rules state that the limit on the deduction of tax-exempt allowances paid by employers to employees using their personal vehicle for business purposes will increase by 5 cents to 50 cents per kilometre for the first 5,000 kilometres driven and 44 cents for each additional kilometre.
Since I get paid .42/km, could I claim .08/km on the first 5000kms and then .02/km on the rest??? Do I need a form for this?

The limit is $.50/km. That means that is the most you can get without paying tax. You don't get to claim the rest from us, it means you can ask your company to pay that without having to pay tax on it.