I'm not sure whether a Puteoli municipal law (perhaps 27 BCE-14 CE or earlier in I BCE) concerned with crucifixion has been posted and discussed here, but here it goes; the following is from Envisioning Crucifixion by J.G. Cook, Novum Testamentum 50 (2008) 262-285):
The lex Puteoli concerns a municipality which decided to contract out the services of an undertaker who doubled as executioner. ... The requirements for the contracted undertaker include the following: the undertaker has to have at least 32 workers, the workers have to be between the ages of twenty and fifty, cannot be knock-kneed, blind in one eye, maimed, have a limp, blind, or branded with tattoos. The funerary workers cannot enter town except when engaging in their trade (getting a body or performing an execution). They must live outside of town and cannot bathe after the first hour of the night and cannot live beyond a tower in the grove of Libitina—which was apparently where some part of their trade was carried out. The workers, when in town, had to wear a colored cap.
The text directly relevant to crucifixion is as follows:
II. 8 Whoever will want to exact punishment on a male slave or female slave at private expense, as he [the owner] who wants the [punishment] to be inflicted, he [the contractor] exacts the punishment in this manner: if he wants [him] to bring the patibulum to the cross, the contractor will have to provide wooden posts, chains, and cords for the floggers and the floggers themselves. And anyone who will want to exact punishment will have to give four sesterces for each of the workers who bring the patibulum and for the floggers and also for the executioner.
11 Whenever a magistrate exacts punishment at public expense, so shall he decree; and whenever it will have been ordered to be ready to carry out the punishment, the contractor will have gratis to set up stakes (cruces), and will have gratis to provide nails, pitch, wax, candles, and those things which are essential for such matters. Also if he will be commanded to drag [the cadaver] out with a hook, he must drag the cadaver itself out, his workers dressed in red, with a bell ringing, to a place where many cadavers will be.