I made a few stops on the way home the other night, which meant my car's engine had to warm up several times and my gas mileage for the trip was down a bit - 55.2 miles a gallon.
Yes, I have a Prius. But normally I can do a few miles a gallon better.
It was late. Orion was high overhead. And as I stood in the driveway gazing at it, I had a diabolical thought.
Normally I put so much effort into increasing my mileage. I drive the speed limit and coast to every red light. For me, putting on the brakes is a failure, a needless conversion of petroleum to brake-pad dust.
Most of the situations I encounter on the highway suggest that drivers don't think much about mileage. They gripe about prices at the pump, but they drive as if every drop were free.
What if I ditched it all and drove like normal people? Just how much of a difference would it make?
This experiment in gas-hog driving would be a big switch. Personally, I think that eking better gas mileage out of one's car is a moral/ethical issue. If one reason we started shooting in Iraq was to preserve our oil supply, don't we owe it to those who died to use the stuff wisely?
Perhaps not surprisingly, that point never goes over too well.
But a lot of people complain about the big oil companies and their massive profits. What better way to game them than to get better gas mileage, keeping your money in your own pocket instead of putting it in theirs?
I began my grand experiment in driving differently the next morning.
Normally, I let gravity carry me down the driveway. This time, I pressed the gas pedal. Wheeee!
One of my first stop signs comes after a hill, then a long level stretch. Normally, I coast. This time, I kept up speed and then applied the brakes. Vigorously.
The Alliance to Save Energy, which has analyzed Department of Energy data and translated it for regular people, contends that avoiding jackrabbit starts and other "aggressive driving" tendencies will improve your mileage by a third.
Out on Route 422, I usually dawdle in the right lane, going with that slower flow. The alliance says that each five miles an hour more than 60 reduces your mileage by about 10 percent.
This time, I braved the left lane. I saw my opening and put on the gas. But - yikes! - these guys were clipping along at 75 miles an hour.
I retreated back to the right lane and waited for my heart to stop pounding. My experiment would have to be somewhat compromised.
Already, it was skewed because I had just had my car tuned up, which can give you 4 percent better fuel efficiency. Presumably the tires were properly inflated (another 3 percent) and the car was filled with the recommended oil (up to 2 percent).
At the inevitable slow-down near Valley Forge, I didn't hang back as usual, keeping my distance from the car in front to even out the speed. I kept pace, punching the gas and then pressing the brakes. My mileage hung in the 40s.
(Yes, in a hybrid, the "regenerative" braking adds juice to the battery, but coasting is still better.)
Then, almost perversely, traffic cleared. How unusual! I sailed along at a constant speed, neither accelerating nor braking. My mileage began to inch back up.
My inner maniac almost lost heart on that glorious downhill sleigh ride along the Schuylkill east of Conshohocken. By Manayunk, my trip's average was up to 52.5 m.p.g.
Would the experiment in inefficient driving fail?
Not so fast. Ahead was construction in the left lane. Traffic went back to its stop-and-start mode. Gas, brake, gas, brake.
There were other downhill stretches, and by the time I pulled into the parking lot at work, my mileage was 53.7.
Just the day before, by doing no more than driving carefully, I had ended the same trip at 65.3 miles a gallon - a 22 percent improvement.
Apply the savings to gasoline that's $4 a gallon - experts say we're headed there - and driving carefully is like paying $3.20 instead.
To top it all off, both trips had taken pretty much the same amount of time.
I got out of my car feeling triumphant.
Until I picked up my briefcase and computer. Hey, weren't they kind of heavy?
The alliance says that losing 100 pounds from the trunk can give you another 2 percent mileage increase. Moi? I'm not some soccer mom with piles of equipment. Just a few reusable grocery bags and some maps, right?
That, it turns out, plus two umbrellas, first aid kit, Swiss army knife, tire gauge, safety pins, coffee mug, flashlight, cell phone charger, pens, stash of reporter notebooks, slippers (don't ask), five audio books, lunch box . . .
I took everything - two loads - inside to a scale. What?! It weighed 41 pounds.
The next day, I vowed, I'd be driving a cleaned-out car, en route to better mileage.
Meanwhile, I've been eyeing the backseat. It sure looks heavy. I wonder if I can remove it without messing anything up.
"GreenSpace" appears every other week, alternating with Art Carey's "Well Being" column. Contact staff writer Sandy Bauers at 215-854-5147, email@example.com, or @sbauers on Twitter. Visit her blog at www.philly.com/greenspace.