Well since I am a commodities trader, I think it is time to set some things straight:
1: Speculators are not responsible for solely moving fuel prices wherever the hell they want them to be.
2: The U.S. government is way more responsible for the prices crude oil and refined products are trading at than anything else and here is why: oil is denominated in US dollars which is a fiat currency. The federal reserve is the visible arm of the international banking cartel and as such they have acquired total control of our money supply. When they print trillions of dollars out of thin air, it makes all the other dollars currently in circulation worth much less. The producing countries who own all the oil don't like this. So they have to increase the prices of their oil to make up for getting paid in ever-cheaper (more worthless) dollars. This unfortunately is an unavoidable consequence of having a fiat currency. Every major currency today is a fiat currency (not backed by anything like gold).
3: Believe it or not, supply and demand are a direct function of international currency flows. Example: right now (May 20, 2010) the price of crude is sitting at $68.01 per barrel. Just a few weeks ago crude was selling for over $84 per barrel. Since the european debt situation is out of control, traders speculate that international demand is dropping and that directly affects domestic demand so that the price needs to drop! Well is your diesel any cheaper at the pump? Of course it is not. So even though traders have dropped the price of crude, products are not coming down in price. SO GET THE IDEA THAT SPECULATORS ARE EVIL OUT OF YOUR HEAD RIGHT NOW! The euro has fallen out of bed, and the european union may very well dissolve sooner than later. So that forex traders have priced up dollars (and other traders: gold, and US governmental debt instruments) WHICH HAS MADE OIL MUCH CHEAPER! Even though you do not see your diesel any cheaper at the pump.
4: Believe it or not, the US government [once again] has its insidious hand in your wallet yet again. The tax charged on every gallon you purchase is actually way more than all the profit that refiners make for turning that crude oil into marketable products. Refining margins are razor thin and these taxes are a big huge factor in the price of diesel.
5: As mentioned earlier, the US government has decreed that all diesel now has to be under 15 ppm sulfur (ULSD). Well that does not happen for free. And the cost is passed directly to the paying customer. And that most definitely is not making diesel any cheaper.
Here are several reasons why diesel fuel is so expensive and not going to get any cheaper. Note that in every instance cited, speculators had nothing to do with the current price of diesel. And that when they do trade the prices up, it is directly because of macroeconomic conditions caused by -you guessed it- governments acting irresponsibly. In fact the stock market is by far the more wretchedly manipulated marketplace compared to the futures markets. The CFTC is all over the commodity futures markets, while the SEC just gives a wink and a nod to what is happening at houses like Goldman Sachs and their high frequency trading (HFT).
Of course the government would love for all of you to believe that it is the evil speculators and traders who are killing people by moving prices up, but unfortunately that is just not the whole truth. Do some research to learn the truth, 'cause you damned sure will NOT GET THE TRUTH FROM THE GOVERNMENT!!!