Relief at the Gas Pump

Gas prices are slowly descending. Drivers in Libertyville and Vernon Hills can finally find gas that is under $4 a gallon—or slightly over $4—for regular.

In Libertyville, the lowest prices reported by Mapquest are $3.98 at BP, 113 N. Milwaukee Ave., and $4.01 at Citgo, 114 Peterson Road.

The Marathon station at 301 Townline Road, Mundelein, has a gallon of regular gas for $3.96, according to Mapquest. At Bucky's Express, 294 E. Townline Road, Vernon Hills, gas is just $4.05 per gallon.

Part of the reason gas prices are on the decline is that the market is switching over to the less expensive winter blend according to Tom Kloza, chief oil analyst at the Oil Price Information Service (OPIS), in The Wall Street Journal MarketWatch.

Nationwide gas prices are currently an average of 3.807 per gallon of regular grade. In Illinois, the average is 3.994. Illinois residents can blame a good part of the cost of a gallon of gas on taxes. Illinois has the seventh highest gasoline tax rate in the country, according to the Tax Foundation.

, but by August prices rapidly rose to more than $4. The rapid rise in Chicagoland gas prices in August was being blamed on a Midwest refinery issue.

The national average is still 30 cents more per gallon than it was a year ago, according to TIME Moneyland.

Historically, gas prices tend to fall from September through Christmas.  AAA expects this trend, which has held true for seven of the previous nine years, to continue in 2012, according to the AAA News Room.