Ruminations of J.net idle rants and ramblings of a code monkey

<RANT>About Drivers and Fuel Economy</RANT>

Idle Babbling

Driving in Houston, for those that have had the joy, is certainly an interesting experience. It's not uncommon to see a dually zipping down the Sam Houston Tollway at 90 MPH, tailgating (and they brake at the last minute when they do this) and weaving in and out of traffic, sometimes with only a foot to spare. Now, while I could just rant a bit on just how, ummm, un-smart this is, I won't. And this is, for me, quite terrifying when I see this as I'm out and about on my motorcycle. Needless to say, any fight between my motorcycle and said dually would result in a somewhat less-than-pretty outcome for me. That said, this type of driver will be something of an example in what follows.

So, here's the deal ... that crazy dually driver is gulping gas at a tremendous rate. Probably getting 5 MPG or so. The vast majority of the vehicles on US highways today are tuned for best highway fuel economy at around 60-70 MPH. Above that and your fuel economy drops exponentially. The exception may be some of the imported German vehicles ... they are designed with the Germany's famous Autobahn in mind. And then, every time he slams on his brakes (to tailgate someone and give himself a bad case of road rage), he's wasting the fuel that got him to that speed.

I'm not going to go into that whole green-environmental-global warming argument. No worries.

Let's do a little math here. Let's say he's going 20 miles on the tollway (that's 1/4 the loop). And he averages - not instant speed, but average, including all that braking - 80 MPH. At 80, it will take him 15 minutes. At 65 (the posted speed), it'll take 18 1/2 minutes. At 70 (the more reasonable speed), it's 17.15 minutes. Not that much time saved. But he's not going to average 90 -- because of constant acceleration an deceleration. He probably won't even average 80. And his fuel economy will be much worse. Let's pretend he drops from 15 MPG at 65 to 10 MPG (and that lower end is generous ... it's likely lower, with all that weight to keep going). At 15 MPG, he'll use 1.3 gallons. At 10, it's 2.0 gallons. At today's average gas price in Houston (3.23/gallon), that an extra $2.26. It doesn't seem like much, but that's just one trip. Driving the same way back, it's $4.50. If this is a regular trip to and from work, that's $22.50/week. At 50 weeks/year, we're at $1125. Now, for me, that's enough to pay for my insurance. His may be higher, depending on how many wrecks he's had and how many tickets. Oh, and getting busted at that speed will not only get you a ticket (for $205), it may well get you locked up for reckless driving (20 MPH over the speed limit). Finally, it's also an additional 1.4 gallons of gas per day. That's an extra 350 gallons/year. And this is a conservative estimate ... I'd bet that his average fuel economy for this trip is under 10 MPG (all that braking and heavy acceleration). Keep in mind that this is just this guy's daily commute.

How much do you want to bet that this'll be the same person that complains the loudest about gas prices?

Even with a typical driver, if you increase your fuel economy by 20%, you're looking at some savings. Assuming you drive 12000 miles per year (about average) and currently get 20 MPG, you would save 100 gallons by increasing your fuel economy by 20%. And this is still less than the US Standard for fuel economy. And, judging from what I've seen drivers doing, I'd bet that we could realistically get better savings.

Looking at the gallons saved, it looks like a drop in the bucket, right? But once you start adding it up for all of the drivers on the highway, you are getting into some serious gallons. Now, before you start going off that I'm getting into an enviro-rant, I'm not. It's a question of national security and the country's overall economy. Oil, the cost of oil and issues related to securing oil resources in an ever-competitive oil market, the US's need to import massive quantities of oil to quench our thirst for driving like maniacs has put is in something of a bad situation. We are completely dependant on other countries for our very economic engine. One of these is Venezuela, which is interesting considering how much Chavez rails against us. And, of course, the Middle East. So much of our foreign policy today relies on ensuring our stream of incoming oil that it often hampers what we can realistically accomplish ... diplomats and policy makers have to keep this in mind. I was young, but I do remember the OPEC oil embargo of the 70's and have read about what it did to our overall economy (it was a Very Bad Thing™). Getting everyone in the country on board is impossible, of course. But a few individuals here and there can add up pretty quickly. There's an estimated 143 million cars in the US ... if just 2% of them improved their fuel economy by 20% using the MPG assumption above, we're at 286 million gallons/year. And there are additional efficiencies and savings that can also be brought into play to multiply this effect.

How to improve mileage? Drive a little slower. You'll be able to get a good idea of where your best efficiency is ... you're tach will tell you. Lower RPM's is better. If you need to stay higher in the RPM's to keep your speed constant, you're wasting gas. Accelerate smoothly and don't floor it. Don't wait until the last minute to break ... just lay off the gas and coast a bit to bleed speed off. This is actually where you get the best mileage (especially at higher speeds) because your engine will be just above an idle ... and that helps your overall average quite a bit. For example, when using a ramp between highways (say the Tollway to I-10), I see many folks keep their speed up while going up the ramp and braking at the last minute. Rather than doing this, let your speed bleed off gradually ... use gravity and the rolling friction of your tires rather than your brakes.  This actually holds for any offr-amp. To do this, make sure you are looking ahead and planning what you're going to do. This is actually a good safety tip and one they drill into you in the motorcycle training course ... and it's made me a better driver in my truck as well. If you're sitting and waiting for someone, just cut off the engine. Sitting still is 0 MPG, so it's a waste. (Don't do this when you are stuck on I-10 during rush hour, though). And try using the cruise control ... it uses just enough gas to keep a constant speed. That task is a little tough for we humans. Finally, track your fuel economy. Set your trip when you fill up and just do a little math at every fill up. Set a target and think about how you drive to get there.

Some things you can't help that will hurt ... rush hour traffic, for example. That's pretty obvious. The terrain you are driving over also has impact ... hilly vs. flat.  Again, this is obvious. Wind plays a huge factor as well, both crosswinds and head winds. I've driven to San Antonio on 30-40 MPH crosswinds and it used much more gas just to stay at 65 MPH. Tailwinds, of course, have a positive effect.

Before I get going, and before you get the urge to try to accuse me of not practicing what I rant, let me get that out of the way right now. I do drive this way. And I also drive a hybrid vehicle. So, I do practice good fuel economy when I'm in my "cage" (that's a biker term for anything with four wheels and is, or can be, enclosed ... convertibles do count). No, it's not a Prius or anything like that ... it's an '07 Ford Escape. It's an SUV. With that vehicle, I typically average 30-32 MPG -- it has readout on fuel economy average, as well as instant economy, so I am pretty aware of how my gas consumption is currently going. It also has a continuously variable transmission, which help keep my engine RPMs at an ideal rate. With a traditional automatic transmission, you'll have to find this. It also cuts out when it's going slow (like rush hour traffic) and that helps a lot. In the worst rush hour traffic, I'll be on the electric motor 80% of the time ... the engine just jumps in to recharge the battery. This technology is continuing to improve and becoming more and more common

My other vehicle is an '07 Kawasaki Ninja 650R. With this one, I typically average just over 40 MPG. I could get it up to around 50 (and I have) depending on how I choose my gear, especially on highway riding, but there's a reason for it. When on the highway, I try to keep my RPM's in the lower edge of the power band. So ... at 70-80 MPH, I'm in 4th or 5th gear, with the RPM's around 6-7000. If I pop it into 6th, I'd be at around 4-5000 RPMs, which is better for fuel economy. But then, on the highway, I want to have the power and acceleration to escape aforementioned dually. And at the lower RPM's, the acceleration is much lower. In 4th or 5th gear, I can get from 75 to 100 MPH is just about 2 seconds. In 6th gear, it takes about 5 seconds. I like having those couple of extra seconds to escape the crazy drivers ... it's a safety thing. Staying at that RPM also allows me to slow down quicker ... letting off the throttle at that RPM range increases the effect of engine braking. That safety thing, however, is not nearly really a concern in a cage. And most of the cars out there can't accelerate fast enough to make much of a difference anyway.

Now ... if you don't drive in a way that helps increase your fuel efficiency, I don't want to hear you complaining about the cost of gas.