It's what keeps the vehicle moving for most vehicles. One day I decided to explore west toward California. I had a cap on my pickup bed. I would sleep in there. No heat. Beginning of my trip I was in the Appalachians. That night it went down to 15 degrees. Boy I felt every one of those ice degrees. Couldn't wait for the sun to come up. I lifted up the cap hatch and looked out, everything was pure white to the tune of 4 inches. Pretty nice cold sight.
I made it to St Louis. Underground is a museum at the arch. I took in a movie on how the arch was built. They built it in two stages. The left and the right and they were built at the same time meeting up in the air at the mid point. The builders had to meet perfectly at the apex, no room for error. They were welded at site, many sections of stainless steel. The base they made would allow them to adjust the sculpture by moving It's base to meet up with the opposing half arch. Super great movie.
I was in western New Mexico at a rest stop. Had breakfast and headed back onto the interstate. I get a nudge to fill up eventhough I had a little less than 3/4 full. I figured I could fill up later down the road. So I kept going. Hot desert driving. The sun bouncing off the hood would score me a nice headache at the end of the day. Should have traveled at night. At a 1/4 tank I kept an eye out for a gas station. No gas to be had, dammit. The needle of gas gauge would hit the very bottom and then bounce up to an 1/8 th of a tank full. Usually there is a 10 mile reserve left in tank when it hits zero. For a hundred miles the needdle would bounce from zero to an 1/8th of a tank. Eventually I saw a California cop parked at side of road giving someone a ticket. I tell him to keep an eye out for me, I didn't think I was going to make a gas station. But there was one up ahead. 100 miles riding on empty... wow.
When I got back home, one day I was low on gas. I was near my old high school. I watched the needle hit the E for empty. That was it the truck stopped. No bouncing needle this time. I walked a quarter mile to get gas. Spirit had my back, back in Calufornia. At that time I didn't know about spirit. But it knew me.
A friend of mine was in the Navy. I guess it was his 4th year. He just completed a double shift. He was out before his head hit the pillow. The next day was a Saturday, his day off. He didn't drive his car for a week. He was sitting in his sport car stewing about his life. He made up his mind, he was going about, he turns the key no gas. He can't believe it. His whole life he was a topper. A person who loves to see a full gas tank. He would fill up even if he needed only 2 gals. He just stared in disbelief..... the ways of spirit. He did quit the navy. A year later, Honorable discharge.