Oil is "pegged" to the dollar because the dollar is a "commodity" now.
If you have "too many" dollars floating around the value goes down. Just like if there is "too much" oil in the marketplace.
So, all prices are "relative" and things only move in relation to other things. Dollar vs Oil vs Eggs vs....
Right now, the impact of Greenspan's Bubblenomic hyper-liquidity experiment is impacting housing AND OIL...both are up because they are "worth more" due to the excess dollars Greenspan "printed" when he tryed to "save the bubble" on Wall Street...