If your employment at a work location is realistically expected to last (and does in fact last) for 1 year or less, the employment is temporary unless there are facts and circumstances that would indicate otherwise.

If your employment at a work location is realistically expected to last for more than 1 year or if there is no realistic expectation that the employment will last for 1 year or less, the employment is not temporary, regardless of whether it actually lasts for more than 1 year.

If employment at a work location initially is realistically expected to last for 1 year or less, but at some later date the employment is realistically expected to last more than 1 year, that employment will be treated as temporary (unless there are facts and circumstances that would indicate otherwise) until your expectation changes. It will not be treated as temporary after the date you determine it will last more than 1 year.

If the temporary work location is beyond the general area of your regular place of work and you stay overnight, you are traveling away from home. You may have deductible travel expenses.
 

Generally, a metropolitan area includes the area within the city limits and the suburbs that are considered part of that metropolitan area.

You cannot deduct daily transportation costs between your home and temporary work sites within your metropolitan area. These are nondeductible commuting expenses.

Two places of work.   If you work at two places in one day, whether or not for the same employer, you can deduct the expense of getting from one workplace to the other. However, if for some personal reason you do not go directly from one location to the other, you cannot deduct more than the amount it would have cost you to go directly from the first location to the second.

Transportation expenses you have in going between home and a part-time job on a day off from your main job are commuting expenses. You cannot deduct them.

Armed Forces reservists.   A meeting of an Armed Forces reserve unit is a second place of business if the meeting is held on a day on which you work at your regular job. You can deduct the expense of getting from one workplace to the other as just discussed under Two places of work.

You usually cannot deduct the expense if the reserve meeting is held on a day on which you do not work at your regular job. In this case, your transportation generally is a nondeductible commuting expense. However, you can deduct your transportation expenses if the location of the meeting is temporary and you have one or more regular places of work.

If you ordinarily work in a particular metropolitan area but not at any specific location and the reserve meeting is held at a temporary location outside that metropolitan area, you can deduct your transportation expenses.

If you travel away from home overnight to attend a guard or reserve meeting, you can deduct your travel expenses.

If you travel more than 100 miles away from home in connection with your performance of services as a member of the reserves, you may be able to deduct some of your reserve-related travel costs as an adjustment to gross income rather than as an itemized deduction. For more information, see Armed Forces Reservists Traveling More Than 100 Miles From Home under Special Rules, in chapter 6 IRS Publication 463.

Commuting expenses.   You cannot deduct the costs of taking a bus, trolley, subway, or taxi, or of driving a car between your home and your main or regular place of work. These costs are personal commuting expenses. You cannot deduct commuting expenses no matter how far your home is from your regular place of work. You cannot deduct commuting expenses even if you work during the commuting trip.