Why are gas prices so different from one county to another? | You asked, we answer

Drivers who commute between Broward and Palm Beach counties may notice a bit of sticker shock when they travel northward over the county line — gas prices seem to shoot up as soon as you cross the border.

One of those frustrated motorists wrote in as part of the Sun Sentinel’s Sound Off South Florida project, in which we attempt to answer reader-submitted questions. “Why is gas so much more expensive in Palm Beach County than Broward County?” the reader wondered. “It’s usually $0.15 higher in Boca than Deerfield.”

It doesn’t help that Deerfield Beach has some of the lowest gas prices in Broward County according to the Gas Buddy app, which tracks gas prices over a given geographic location, and that Boca Raton has among the highest in Palm Beach County.

But county-wide averages show that Palm Beach County as a whole does stand out for its priciness.

“A big thing to consider, which is likely the key here, is transportation costs, due to the distance to the supply source,” said Mark Jenkins, a consultant with the American Automobile Association. “The majority of the gasoline in your region comes from Port Everglades. Although some gasoline comes in through the Port of Palm Beach, the bulk of fuel imports is diesel. So the fact that gasoline has to be trucked from Port Everglades to Palm Beach, means transportation fees.”

Slight differences between locations can also occur because of what retailers believe the market will bear. Jenkins allowed that it’s a possibility Palm Beach County is more expensive based on higher median household income, though he said he did not have data to support the idea.

According to census data, the median household income in Palm Beach County is $53,242, while the median household income in Broward County is $51,694. Put another way, the median household income in Palm Beach County is 9.7 percent higher than in Broward, or just slightly more than the increased cost of gas.

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dsweeney@SunSentinel.com, 954-356-4605 or Twitter @Daniel_Sweeney