Can I claim commuting expenses for a temporary job assignment?

This is my job description...Postal Support Employees (PSE) hold temporary appointments for periods not-to-exceed 360 days. Subsequent appointments after a 5 day break in service may be offered but are not guaranteed and should not be expected because the use of PSEs is discretionary and subject to business needs...Also I drive 90 miles per day.  Can I file a deduction?