You‘ve probably noticed that gas prices are falling fast.

A few weeks ago, problems with refineries in northwest Indiana and Illinois caused prices to spike as high as 4.29 per gallon.

Now, you can find gas for a full dollar-per-gallon less in some parts of Indianapolis, according to   Patrick DeHaan, Senior Petroleum Analyst with Gas Buddy, says the average prices for metro Indy is now 3.53 per gallon for regular unleaded, a drop of 30 cents from this time last week.

Part of the reason is the refineries that have come back online, but DeHaan also says economic jitters are playing a role.  Anxiety over the Federal Reserve possibly ending it‘s effort to stimulate the economy with extra dollars.

The Fed‘s announcement that it believes the economy may be strong enough to survive without the stimulus sent stock prices down, and DeHaan says it sent the price of oil down, too, as traders wonder whether people will use as much oil if the economy slows.

The drop in gas prices is expected to continue at least through this week, as DeHaan says the wholesale price of gasoline continues to fall.  The U.S. is also starting to produce more of its own oil – thanks largely to fracking and other new technologies, the country is on track to produce more oil than it imports this year for the first time since the 1990‘s.

But DeHaan says having more crude here will not translate into lower gas prices unless more refining capacity is added.  He says capacity is especially tight in the Midwest, where any refinery problems can lead to price spikes like the one from a few weeks ago.