Its not just gas. Everything that we know of will continue to increase in price. It does vary on a day to day basis, but overall the price for almost everything has been rising over the past few decades. Its called inflation. As the government prints more money the value of each dollar decreases. The more money there is in relation to the population, the less valuable the money becomes. The less valuable to the money becomes, the more money is required to pay for the same service or product. If I was the only person on Earth and I had a billion dollars, each dollar to me wouldn't be worth that much. If I lost 1 dollar I wouldn't notice a difference. But if a billion people each had 1 dollar each dollar would be worth a lot more. Even if I was the only person on Earth, if I had the only dollar in the world that dollar would have some value over other objects that are frequently found but not necessary for my survival. If I lost that 1 dollar, I would notice it missing. Our economy is set up to do nothing but inflate as money can be "printed" (it is usually created electronically.) and can increase the amount of money that is in the economy by a considerable amount. This may temporarily help businesses but would only ultimately lead to inflation. It we continue to inflate the currency expect prices to continue to rise.
I'd like to mention that it seems inflation affects different parts of the market in different ways. It depends on how involved the government is and what products we are discussing. Milk has steady been going up little by little. A gallon of milk today can be compared to a gallon of milk 30 years ago even if the process by which the milk is produced, stored, or preserved changes. However a TV from 30 years ago is not as comparable to a digital high definition 3d tv of today. This is important to understanding price changing, as with milk the price change can be almost completely attributed to inflation. But the TV has too many other factors to be evidence of inflation. That being said the greatest indication of inflation is gold and silver. Gold hasn't changed at all in thousands of years. A gold ring from a hundred years ago is still a gold ring today. Gas is sort of like milk in a sense. The production, storing, and preservation of gas may have changed, but a gallon of gas today was still a gallon of gas 30 years ago. It also appears as though things in which the government heavily regulates have gone up in prices at a higher rate compared to things the government doesn't regulate. Health care, energy, an agriculture have become considerably expensive. Compare this to things that are not as heavily regulated, like video games. Other than giving games ratings, the government does little to actually dictate what games can or cannot be sold and how those games are produced. Yet even with all of the time and energy put into games, the price of a brand new game has actually stayed the same or even deceased some. Even as the time put into creating a video game, the technology used to create it, and the number of people involved in the production of games, and the demand for video games have risen significantly compared to the days of Atari and Sega.
But to answer your question, due to government regulation and inflation the price of gas will stay high and continue to rise significantly.