Transportation to the Job

I want to pay my employees part of their gas because they live a distance from the job - but it IS THEIR REGULAR JOB, we are not talking about different job sites. I realize that this is taxable but must CPP and EI be applied as well?

Generally if an amount paid to an employee is taxable, it is also pensionable and insurable ... so deduct CPP, EI, and income tax.

CRA's publication T4130 Employers' Guide - Taxable Benefits and Allowances has a benefits chart on the last two pages which shows if you include GST/HST on the benefit/allowance and whether you are required to withhold CPP & EI, along with the T4 codes.