Top left and right: While Travis is driving a prostitute and her client (top left; click image to enlarge), we are briefly shown the cab fare meter reading '315' (top right). Above left: After dropping the pair off, Travis gives the cab a washing as he passes near an open fire hydrant, on his way back to the cab company's garage. Above right: At the garage, Travis is here shown having just cleaned off the rear seat of his cab with the rag he's holding. We hear his voice-over saying, "Each night when I return the cab to the garage I have to clean the come off the back seat. Some nights I clean off the blood."
The '315' in the top right screencap above refers to the bible's 3rd book, Leviticus, chapter 15, which falls under the heading Discharges Causing Uncleanliness. Verses 1-11 of this chapter read as follows [New International Version]:
1. The Lord said to Moses and Aaron, 2. "Speak to the Israelites and say to them: 'When any man has an unusual bodily discharge, such a discharge is unclean. 3. Whether it continues flowing from his body or is blocked, it will make him unclean. This is how his discharge will bring about uncleanness: 4. Any bed the man with a discharge lies on will be unclean, and anything he sits on will be unclean. 5. Anyone who touches his bed must wash their clothes and bathe with water, and they will be unclean till evening. 6. Whoever sits on anything that the man with a discharge sat on must wash their clothes and bathe with water, and they will be unclean till evening. 7. Whoever touches the man who has a discharge must wash their clothes and bathe with water, and they will be unclean till evening. 8. If the man with the discharge spits on anyone who is clean, they must wash their clothes and bathe with water, and they will be unclean till evening. 9. Everything the man sits on when riding will be unclean, 10. and whoever touches any of the things that were under him will be unclean till evening; whoever picks up those things must wash their clothes and bathe with water, and they will be unclean till evening. 11. Anyone the man with a discharge touches without rinsing his hands with water must wash their clothes and bathe with water, and they will be unclean till evening.' "
Some of the men who ride in the back of Travis's cab have sex with prostitutes, and thus may have contracted one or more sexually transmitted diseases, some of which can cause unusual discharges from the body. (For example, gonorrhea can cause a white, yellow, or green discharge from the penis.[a]) Then, in accordance with the above verses, the rear cab seat becomes 'unclean' when a man with such a disease sits on it, and thus, Travis himself may become unclean in the process of cleaning off the seat later, for example, if he sits on the seat while reaching with his rag to clean part of it. Travis would also become unclean if he touches such a man while collecting the fare from him, or in other scenarios in which he might touch the man, or the man might touch him. In strict accordance with the Leviticus verses, if one or more of the foregoing occurs, Travis must wash his clothes and bathe with water, and he will be unclean "till evening."
a. National Institutes of Health Medline Plus Gonorrhea page.
