Texas Government Code - GOV'T § 432.192. Witnesses' Expenses

(a) Persons in the employ of this state but not belonging to its military forces if traveling on summons as witnesses before military courts, are entitled to round trip transportation between their place of residence and the place where the court is in session. If transportation is not furnished, they are entitled to reimbursement of the cost of travel actually performed by the shortest usually traveled route and to reimbursement of the actual cost of meals and rooms at a rate not to exceed $25 a day for each actually and unavoidably consumed in travel or in attendance on the court under the order or summons. Allowance may not be made to them if attendance on court does not require them to leave their place of residence.

(b) A person not in the employ of this state and not belonging to its active military forces, who has been duly summoned to appear as a witness before a military court, is entitled to receive $50 a day for each day actually in attendance on the court, and 12 cents a mile for going from his place of residence to the place of trial or hearing, and 12 cents a mile for returning. Civilian witnesses will be paid by the Texas military forces.

(c) The charges for return journeys of witnesses shall be made on the basis of the actual charges allowed for travel to the court, and the entire account thus completed in this manner shall be paid on discharge from attendance without waiting for completion of return travel.

(d) Fees may not be allowed to a person as witness fees, unless the person has been subpoenaed, attached, or recognized as a witness in the case.