Fuel Gauge

Mileage Experts Say Slow Down and Don't Use the Luggage Rack

Jason Toews is the co-founder of GasBuddy.com, which helps people find cheap gas (if such a product actually exists). This is Memorial Day weekend, the official start of the summer driving season, when drivers traditionally pay closer attention to gas prices.

This should be Toews's moment, his 15 minutes of fame, his day in the sun, his flash in the pan -- step right up and choose your cliche.

But with gas prices soaring, now topping $4 a gallon, it turns out that every day has become Toews's moment. "It will come up in virtually every conversation when people talk to me," he said. "It does get tiring if I am trying to enjoy a meal. But it's a subject that everyone is talking about. And gas prices are only going to go higher."

He cites statistics as if he were reading them off the back of a baseball card. When The Post spoke to him Thursday, he noted that the average price per gallon had gone up 3.5 cents -- in 15 hours. "Thursday seems to be a pretty popular day to raise prices," Toews said, even when it's not Memorial Day weekend. He's such a gas man that he knows the days when prices go up! (Sunday and Wednesday are cheaper.)

More stats for the weary: Marylanders hitting the road for the long weekend are gassing up at an average of $3.80 per gallon, the price earlier this week. Last year at this time the price was $3.12. If you are keeping score at home, that's a 22 percent increase. The national average has gone from $3.20 a gallon to $3.80 in the same period, according to the AAA.

Susan Uttal of Potomac is still planning to take a trip to the Outer Banks this summer. "How can I change my vacation plans?" she said. "Stay home? That's not going to happen. I stay home enough. My basic traveling is from home to work."

So how can drivers like Uttal get through these tough times? Is it cheaper to drive south or north for a vacation? What about luggage racks on the roof? Good idea or bad? How far should you drive for cheap gas? Will slowing down on the highway, the bane of many existences, really help?

We'll try to sort all that out.

You're not in an action movie

Oh sure, it looks like fun, driving away in a great escape scene, bad guys clinging to the roof. But that is so, so wrong. It is so bad for gas mileage. Edmunds.com, in a test of aerodynamics and fuel economy, recently proved this (using a vehicle with luggage -- not people -- strapped to the roof).

The automotive Web site found that in testing on an SUV, putting a suitcase and cooler on the roof -- while driving at 65 mph -- dropped fuel economy from 27.2 mpg to 21.6 mpg. Here's why: Adding stuff on the roof increases the amount of car that has to fight through the wind, creating drag.

As Edmunds.com explained, "Aerodynamic drag increases in proportion to the square of speed, so doubling speed from 40 to 80 mph results in a quadrupling -- four times more -- of drag."

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