Per the Form 2016 instructions:
Commuting. Generally, commuting is travel between your home and a work location. However, travel that meets any of the following conditions is not commuting. You have at least one regular work location away from your home and the travel is to a temporary work location in the same trade or business, regardless of the distance. Generally, a temporary work location is one where your employment is expected to last 1 year or less. See Pub. 463 for more details. The travel is to a temporary work location outside the metropolitan area where you live and normally work. Your home is your principal place of business under section 280A(c)(1)(A) (for purposes of deducting expenses for business use of your home) and the travel is to another work location in the same trade or business, regardless of whether that location is regular or temporary and regardless of distance.
You would take the per mileage deduction on column A, line 1 of the form offsetting by reimbursements on line 7 of column a. See above for which miles count for deducting.