Keeping an Eye on Traffic

The US Department of Transportation's Federal Highway Administration maintains a traffic monitoring program. Based on a network of some 4000 sensors on roads, streets and highways across the nation they can esimate the total number of vehicle miles driven in a given hour, day or month. Vehicle miles is a way of measuring a combination of how many vehicles were moving and how far they moved. One vehicle mile could mean a single car drove a mile or that 4 cars each covered a quarter mile. The graph to the side shows the traffic volume for the entire US averaged over a 12 month window. This is interesting, because the amount of fuel used by the nation principally depends on two things. One is how many vehicle miles we are driving and the second is how much gas it takes on average to move a vehicle a mile. This graph shows that vehicle miles traveled goes in one direction - up. Until the summer of 2008 that is. You can see how the $4.00 gasoline we had at that time caused an unprecedented crash in the amount of driving.

OIl Producing Countries in Decline

Gas comes from oil, and it looks like very soon the global production of oil will not be able to satisfy the demand for it. This simple idea is known as Peak Oil. The International Energy Agency (IEA) has warned us that the day of supply less than demand is coming. Here is data taken from the IEA Oil Market Report of September 2009 showing the declining output in some oil producing countries.

Oil Producing Countries With Declining Output

Country	Year (Million Barrels per Day)
	1998	2003	2008
Nigeria	2.11	2.15	1.95
Venezuela	3.12	2.36	2.35
United States	8.37	7.83	7.52
Mexico	3.50	3.79	3.16
United Kingdom	2.84	2.28	1.56
Norway	3.14	3.26	2.46
Australia	0.71	0.67	0.56
Indonesia	1.55	1.71	1.03
Argentina	0.90	0.83	0.75
Colombia	0.82	0.55	0.59
Oman	0.90	0.82	0.75
Yemen	0.40	0.45	0.31
Syria	0.57	0.53	0.39
Gabon	0.35	0.25	0.21
Egypt	0.87	0.71	0.65
Totals	30.15	28.19	24.23

Lower production of oil means less gasoline, which in turn means much higher gasoline prices. As each new country sees its production decline it will necessarily go looking for imports. The more importers there are in the market, the higher the oil price. These numbers are good motivation for starting to save on gas now!

Your Gas Cap

Gasoline, especially winter gasoline with plenty of butane, has a high vapor pressure and will evaporate quickly if exposed to the open air. A properly secured gas cap will keep the evaporated fuel under pressure in your gas tank and stop it from escaping into the atmosphere. This saves you money by reducing lost fuel and also helps air quality. Gasoline vapor is a heavy contributor to smog. A loose gas cap can easily emit more hydrocarbons due to evaporation from a parked vehicle than would be emitted by the running engine. This is because of the almost complete combustion of fuel.

So if you have a damaged gas cap or if you have lost it and been running without, think about replacing it today. You will save a lot of otherwise wasted gas and cut down on smog.

Bridges and Bottlenecks

Bridges are something that most drivers take for granted. They enable some really impressive shortcuts. Yet the nation's bridge population is old and in need of maintenance. Even now important bridges are closed. The Bay Bridge in Oakland, a 73 year old piece of critical infrastructure is closed to traffic. The Lake Champlain Bridge is also shut.

Given the very high levels of federal and state government debt and the poor condition of the country's bridges I think we will be seeing more and more closures in the years ahead. A cash strapped state or local government might find it does not have the budget to make repairs. Bridges could be shut for extended periods.

Try to become aware of the bridges along your commonly driven routes. They don't have to be bay crossing monsters. Even a small bridge over a dry ravine can be critical in a route. Having an awareness of the infrastructure that lets you drive carefree where you want will help you cope if that infrastructure fails. Also if you find yourself planning a move, you might want to include a study of bridge layout when evaluating your options. Living in a city or region that is heavily dependent on bridges could prove to be a mobility limiting headache over the next decade or so.

Give Your Transmission A Rest

If you drive a manual transmission vehicle, you always shift into neutral when you are waiting for a light or at a stop sign. But if you have an automatic transmission you probably leave it in gear. Remember that the transmission's job is to let the engine run in a narrow range of speeds (where it is most powerful or efficient) while using different gear ratios to provide a wide range of vehicle speeds. But how does this allow you to stop your car while the engine is running? The engine is still turning over but the output speed is zero. This would mean that the transmission would have to provide a gear ratio of zero. In fact it does not.

The torque converter is what allows a vehicle with automatic transmission to stop in gear while the engine is still turning over. In a manual transmission, the clutch directly connects the flywheel to the input of the transmission and so both have to stop together. Torque converters use a fluid coupling system to connect the engine's flywheel and the input of the transmission. With a torque converter there is no direct mechanical contact. Because fluid is used to make the connection, the flywheel can be turning while the output of the torque converter remains stationary. When you are stopped at a light in gear, the engine is turning over but the torque converter passes only a very small torque on. This small torque can be easily resisted by the brakes.

Using your brakes while stopped in gear thus puts extra load on your engine. This extra load will result in using more gas. If you have an automatic transmission shift to neutral when you are stopped. Not only will it reduce engine load a little and save you some gas, but it will give your torque converter a chance to cool down.

Bad Bridge Maps

When you are doing your route planning you may find yourself with the choice to cross a bridge or not. Perhaps you have heard about the thousands of deficient bridges scattered across the nation and wondered whether the bridge you are choosing to cross or avoid is one of them. Well, the Bureau of Transportation Statistics has a map showing the locations of the structurally deficient bridges on the National Highway System. You select the state you are interested in. Then you can choose to see a map for that entire state or for one of the individual congressional districts it contains. Each deficient bridge is marked with a green dot. For example, the map for Idaho is shown below. Also available below the image is a table of data giving the bridge's label and structure id number as well as the highway it is on and a rough description of where it is along that highway.


Being paranoid is never a good idea, and going far out of your way to avoid a bad bridge could cost you a lot of extra gas. But if you are the cautious type and have an easily avoided bad bridge on your commute (or otherwise well beaten path) you could choose to go another route.

High School Students Build a Solar Car

This video shows how a group of high school students build a solar powered car. Solar power is the ultimate in saving on gas. No gasoline used. No electricity used. The car they built looks like a box on wheels, but it uses 0.00 gallons per hundred miles travelled. It is impossible to beat that!

Truck Tailgating

Can you save gas by tailgating a semi? The idea is that the semi will force its way through the air, leaving a low pressure zone in its wake. If you can get your car into that low pressure zone, you will experience less air resistance. In turn that gives you better gas mileage. This principle applies when birds fly in V-shaped flocks. The leader opens a low pressure path in the air, making the journey easier for all of the following birds.

In the hypermiling lexicon this is known as drafting. The low pressure zone is not very large. The best area for drafting occurs within a distance of a couple of truck widths behind the truck. That is about 20 feet. The problem is that at highway speeds of 60 miles per hour, your car will cover those 20 feet in about one tenth of a second. This gives you essentially no time to react if the truck suddenly stops. Staying in this zone could give you up to a 20% reduction in gallons per hundred miles consumed. But tailgating is not only dangerous, it is illegal in many zones of the world. So the recommendation is to give tailgating a pass.

National Lampoon Saves On Gas

Time for some Friday gas mileage humor. The video lampoons a bunch of gas saving tips. Each tip is actually a good idea which would get you better gas mileage. Taken to extremes they are funny. Watch and have a laugh!

Here is a list of the tips lampooned in the video.

1. Route planning: just go in a straight line!


2. Hill avoidance: go right on over!


3. Carpooling: pack in 40 people!


4. Weight Reduction: throw out the headrests, the seats and starve your children!


5. Drafting (potentially dangerous hypermiling technique): use a grappling hook to hitch a ride on an 18 wheeler!

Engine Emissions

Operating engines consumes fuel, delivers useful work and produces emissions. Left uncontrolled, those emissions can produce blankets of smog that nobody wants. Using less gas will also produce less pollution. Pollution levels are also controlled by use of emission reduction technologies and fuels. What is in the emissions coming out of your tailpipe? You will find that almost all of them are one of the following five things.

1. 
   Hydrocarbons C_nH_m: these are the fuel itself. If the fuel is not completely burned up in the combustion process, whatever is left over must come out the tailpipe. Engines running rich (with excess fuel relative to the amount of air in the cylinder) will emit hydrocarbons. It is also possible to find hydrocarbons in the exhaust if the engine is running very lean (excess air relative to fuel) because sometimes under lean conditions the combustion does not get going at all or does not complete, leaving fuel in the exhaust.
   
   These hydrocarbons are the dominant component in ground hugging smog. Mixed with nitrogen oxides
   in the sunlight they combine to form ozone. Low level ozone is a health hazard.
   


2. 
   Carbon Dioxide CO₂: completely burned fuel. Thermodynamics shows us that the most stable combination of Carbon and Oxygen is as carbon dioxide. Thus whenever possible combustion continues to this stage.
   
   Carbon dioxide has no adverse health effects but famously contributes to global climate change. One of the big villains on an international scale.
   


3. 
   Carbon Monoxide CO: incompletely burned fuel. Combustion favors the attachment of two Oxygen atoms to each Carbon atom. In rich conditions there might not be enough Oxygen to go around. Thus CO will tend to be produced in rich burn and very little or none will be produced in lean conditions.
   
   Carbon Monoxide is poisonous. Not a good thing.
   


4. 
   Oxygen O₂ : from incompletely burned air. Just as running rich can leave some fuel unburned in the combustion process, running lean can leave unburned Oxygen.
   
   This oxygen was in the air anyway before it got ingested into your engine. So this one is no problem.
   


5. 
   Nitrogen Oxides NO_x : from the combustion of the Nitrogen in the air. Air is a mixture of gases containing about 70% N₂. At high temperatures some of this reacts with the Oxygen in the cylinders producing NO_x.
   
   NO_x is a health hazard. They cause lung damage in low concentrations and can be outright fatal at high concentrations. They also corrode metals, eat away at fabrics and kill plants.
   

Just think: when you reduce gas consumption, you also reduce production of all of these emissions. Yet more reasons to save on gas! Better gas mileage helps a lot more than just your wallet.

Watch a Hypermiler Saving on Gas

Here is another hypermiler doing his thing. Hypermiling is the skill of driving in such a way as to minimize fuel use. You can see in the video that he is using the Scan Gauge II. The feedback generated by seeing your instantaneous fuel consumption rate really helps you learn to reduce it. The first tip given in the video is to coast in neutral with the engine on whenever you know you will not need to accelerate for the next while. His Scan Gauge clearly shows the benefit of coasting ... he gets 170 miles per gallon or uses only 0.59 GPHM (gallons per hundred miles). That is saving on gas!



The video gives the Hypermiler's Golden Rule: Maintain Momentum. Every time you slow down, you are dumping kinetic energy into heat and brake dust. When you speed up again, that energy has to be replaced and it comes from your gas tank. The video also shows a driver honking at the hypermiler as he slowly accelerates away from a light. You will likely encounter this kind of anti hypermiling peer pressure. It is a symptom of the almost total lack of hypermiling culture in the US. Maybe putting up a bumper sticker like in the image above could help!

Some Hypermiling Habits

Your habits can add up to have big effect on your life. Some are good and some are bad. In the case of fuel economy, developing a few simple hypermiling habits can noticeably boost your fuel economy without costing you anything. So without further ado, here are nine ways you can modify your driving without breaking the law or doing anything dangerous.

1. Don't speed. Stick to the limit.


2. Reduce your use of the brakes ... only when you have to


3. Don't idle your car. Turn it off.


4. Check your oil level and tire pressure regularly


5. Drive smoothly avoiding unnecessary and rapid acceleration


6. Try to slow down without actually stopping at signals


7. Never accelerate toward signals


8. Cut down on air conditioning use


9. Plan your route to reduce driving

Tour an Oil Refinery

Refining is the process that converts crude petroleum into a range of blending components which are in turn combined to make gasoline. Although refining is fundamental to the modern way of life, it is something that takes place out of sight. This video gives you a virtual tour of the American Refining Group refinery in Bradford Pennsylvania. Enjoy!

Four Reasons to Save on Gas

Why go to the trouble of learning hypermiling culture and buying fuel efficient vehicles? Well, here are four reasons why you might do just that.

Number one is the money you can save. Saving on gas means you will be shoveling out less cash each time you fill up. Remember when the price of gas was at $4.00 per gallon? Well, that can come back. Just because right now today the price is under $3.00 per gallon does not mean it will stay there. And if the price of gas soars having a fuel efficient vehicle can put a lot of money back in your wallet.

Number two is you can reduce the dependence of the nation on imported oil. The US now spends something north of $400 billion dollars a year on oil imports. That makes the nation very vulnerable to oil market moves. An increase in fleet fuel efficiency nationwide of only 10% would keep $40 billion dollars in the US economy. That is a lot of money.

Number three is peak oil. Petroleum is a non renewable resource. One day soon it will no longer be possible to increase the extraction rate. However, the demand for oil will almost certainly keep growing as the global population rises and developed nations like China and India increase their standard of living. That means we will enter into an era of permanently high oil prices. The less gas we use now, the more prepared we will be.

Number four is climate change. Using less gas will dump less carbon dioxide into the atmosphere. And dumping less CO₂ certainly cannot hurt the climate.

So start introducing yourself to hypermiling culture. You can help yourself, the nation and the world.

Route Planning to Minimize Gas Use

When you have a choice of routes for example for your commute, sometimes choosing the longer one can save you gas overall. A route that lets you drive smoothly at a lower speed without accelerating and stopping will give you better gas mileage. But if the smooth route is a lot longer, it might actually cost you more gas overall, even though you get better MPG. Remember that your real goal is to minimize fuel use, not maximize fuel economy. Of course these two goals are normally the same thing. If you are traveling a fixed distance for example because you don't have a choice of routes then better fuel economy will give you less gas use overall. But when the route or distance itself becomes a variable, then sometimes the shorter route that gives you lower fuel economy could be better. For example, if you have an amphicar, you won't get very good mileage, but shortcutting across a lake could save you so much distance you use less gas overall. Or more realistically, it could be that you can choose to take your commute route over a steep hill. Going over that hill will lower your mileage drastically, but if the distance you save is great enough you could use less gas overall on the commute.

Think about the routes you can take to get where you want to go. Try to pick the one that balances opportunities for smooth, slow travel (use less gas per mile) and cuts down on the total distance. You want to choose the one that uses the least gas along the trip.

World Without Oil

The World Without Oil is a website telling a story about what an oil crisis in the United States might be like. The story is told from the point of view that it is real, with blog posts and videos supposedly describing the daily situation. Sort of like the modern marketing campaigns for the television series Lost or the vampire series True Blood. The story covers a 32 week period over which the price of gasoline rises to $8 per gallon. There has been a lot of work put into this story. One problem is the format. Being spread out over simulated blog posts and news stories etc it feels somewhat incoherent. But if you want to instill hypermiling culture in the USA I guess writing stories like this one can only help. If you like disaster stories and are interested in saving on gas, you might be interested in World Without Oil.

Do You Know How Many Miles You Drive?

The Center for Transportation Analysis of the Oak Ridge National Laboratory has a publication called the Transportation Energy Data Book. In it you can find all sorts of interesting data. There is a section called Self-Reported vs.Odometer Average Annual Miles available as a Microsoft Excel spreadsheet. One fundamental principle of saving on gas is that you have to know how much you are using to know if you are saving or not. You have to know how much gas you are putting in your tank how often and how many miles you are driving in between fills. Getting into the habit of watching these things is important. Otherwise it is all too easy to forget everything except for the last fill up. That can convince you of things that are not true.

For example, maybe you tried a new hypermiling technique for a couple of days. Then you went to the pump and were surprised at how much money the bill was. You conclude the technique did't work. But what you might not be aware of is that you actually drove quite a few more miles before that fill. Or maybe traffic was especially bad. You have to keep a long term watch over what is going on.

Anyway, the interesting thing about the self reporting odometer study done by Oak Ridge is that on average people do not know how far they drive in a year. I have reproduced the data from the study here.

Self-Reported vs. Odometer Average Annual Miles, 1995 NPTS and 2001 NHTS

Vehicle age (years)	1995 self-reported	1995 odometer	2001 self-reported	2001 odometer
Under 1	15,900	15,600	15,500	14,500
1	16,800	14,500	14,300	14,200
2	15,500	14,800	14,000	13,700
3	14,400	13,800	13,100	14,100
4	14,100	12,900	12,500	13,400
5	13,500	12,700	12,000	12,900
6	13,200	12,400	11,800	12,400
7	12,800	11,600	11,600	12,100
8	12,200	11,300	10,900	11,300
9	12,200	11,200	10,800	10,500
10 and older	8,900	9,000	7,400	8,100
All household vehicles	12,200	11,800	11,000	11,800

The study was done twice, once in 1995 and again in 2001. Both times Americans said they traveled an annual distance that the odometer disagreed with. One observation is that in the years between the studies, the error switched sides. In 1995 Americans thought they drove more than they actually had. This conservative estimate would help to reduce gas usage and let families build a little safety into their financial planning. But in 2001 Americans thought they had driven less than they really did. This is a worrying trend. Underestimating your driving is likely to discourage efforts to save on gas. It also throws off family budgeting because it will generate unexpected shortfalls. Kind of like the "all risk" style of modern banking.

Hypermiling Culture

Hypermiling is the skill of driving in a way that maximizes fuel economy. The fact is that in the US very few people have this skill. That is not surprising because it is not valued. Fuel economy has been a very low priority in America for decades. Witness the focus on miles per gallon here versus liters per 100 kilometers in Europe. In the US we want to know how far we can go on a tank of gas. In Europe they want to know how much gas it will cost them to cover the distance they must travel. India it seems falls in the European camp. This page has a video which shows signs installed in Calcutta which display hypermiling driving tips to the public.

The sooner that hypermiling culture starts to flourish in the US the better. Although better engine efficiency, improved aerodynamics and other technologies can help save on gas, the biggest single factor controlling gas usage is how much you drive and how you drive. If you are constantly doing jackrabbit starts, zooming up to the next light and slamming on the brakes to a complete stop you will use a lot of gas no matter how aerodynamic your car is.

Drive Smarter Challenge

Drive Smarter Challenge is a website that provides a calculator showing how much you could save on gas using different tips and tactics. You have to tell them the make, model and year of your car as well as how many cylinders it has. They ask for your zip code too. One strange thing is that the website does not seem to know when a certain make or model has only one possible number of cylinders. Even if there is only one option, you have to choose it.

Then you can choose any combination of six maintenance and driving tips. The website then estimates how much you would spend in gas over a year. It assumes you drive the national average of 12,500 miles yearly and a gasoline price of $2.33 per gallon. The idea is you can see what money amount you could save by adopting better maintenance habits or more fuel economic driving patterns. The tips I got when I went through the site were:

1. Keep Tires Properly Inflated
2. Choose the right oil!
3. Reduce your Vehicle Miles Travelled
4. Curb aggressive driving!
5. Drive sensibly!
6. Ditch the "junk in the trunk"!

Then at the end it gives you a list of how much you saved on dollars, gallons of gas and CO₂ emissions. It invites you to challenge your friends and offers some coupons.


The picture above shows one of the tips with the buttons to accept or decline it. All of the tips are sensible, basic gas saving measures that will pay you back. The single tip with the biggest potential impact is of course Reduce Your Vehicle Miles Traveled. The website says it can save up to 5% of your gas, but that is way too low. You can potentially reduce your fuel expenditures by 100% if you go hardcore walking and bicycling.

National Fuel Gauge Reading Full

The Energy Information Administration keeps track of the total amount of gasoline in storage in the United States. This information is of interest because historically when the amount is low, the price of gasoline rises. This can happen regardless of the price of oil, the bottom of the pyramid in the gasoline production chain. Short term gas prices are set by the relation between demand for gasoline and the supply available. The EIA publishes a report called the Weekly Petroleum Status Report where you can always find the latest updated information.

In the graph, taken from the current Weekly Petroleum Status Report you can see how in September 2008 the amount of gasoline was well below the gray average band. We also had record fuel prices in that time. Right now the national gasoline supply is above average. Good news for drivers! Keeping an eye on this graph is like keeping an eye on the nation's fuel gauge. When it starts dropping below the average range, watch out for high gas prices!

Winter Gasoline: What is the Difference?

Every year in the Fall we hear about how the gas stations are switching over to winter gasoline. The good news is that winter gasoline is a little cheaper. Have you ever wondered what the difference between winter and summer gasoline is and why one is cheaper than the other?

Gasoline is made from crude oil. Crude oil consists of a wide mix of chemicals. Refineries process crude oil and separate out the various constituents. These products are then blended into gasoline. The refinery does not convert crude oil directly into gasoline. What actually happens is the refinery uses the crude oil to make blending components which are then combined to make gasoline. Refineries have a multitude of operating units, some of which could be catalytic crackers, alkylate units and reformers. Each has a different cost to run.

When gasoline is made by blending these components, there are certain specifications that must be met. One of them is the octane rating. Another very important but less well known specification is the vapor pressure of the gas. Every fluid has a vapor pressure that depends on the temperature. Higher temperature gives more vapor pressure. When the vapor pressure is greater than the atmospheric pressure, the liquid will boil. For example, water at sea level boils at 100 degrees Celsius because water at that temperature has a vapor pressure of one atmosphere. If you climb a mountain, the water will boil at a lower temperature because the air pressure at altitude is lower. Thus the water vapor pressure reaches the air pressure at a lower temperature. The result of trying to cook in water that is boiling at a lower temperature is that you have to wait longer for your food to be done.

The vapor pressure of gasoline also rises with temperature. That means that in the baking heat of summer, the vapor pressure of gasoline in your car's fuel tank might rise up above atmospheric pressure. That would make it boil, filling your tank with gas fumes. The gas will escape into the atmosphere, causing pollution. To reduce that pollution, the gasoline must be changed so it has a lower vapor pressure at a given temperature.

The vapor pressure of gasoline depends on the components that are blended to make it. One of the cheapest gasoline blending components is butane. Butane also has a very high vapor pressure. So in the summer, gasoline has to be made with very little butane. That butane must be replaced with something more expensive. In the winter, when temperatures and thus vapor pressures are lower, cheap butane may be used in greater amounts.

So the big difference between summer and winter gasoline is the amount of butane blended in to make the gasoline. The cheap butane means winter gasoline can be a little cheaper too. Next time you hear about winter gasoline you will know what they mean. Winter gasoline means more butane!

Ride On Nitrogen Initiative

Nitrogen in your tires can provide some benefits. Nitrogen does not leak out of your tires as fast as oxygen, so filling tires with pure nitrogen can help pressure retention. This means if you forget to check your tire pressure regularly you are less likely to drive on underinflated tires. And with the busy schedules of today, most people have trouble regularly checking their tire pressure. Of course regular air is 78% nitrogen already, so you cannot expect gigantic changes. Only the 22% that is not nitrogen is leaking out faster.

The second advantage of nitrogen is that it is less temperature sensitive than pure air. The temperature will be lower when you first start driving than after some road time. That means at the start of your trip you will be effectively driving on underinflated tires. That costs gas and increases tire wear. Pure nitrogen tires will suffer less from this effect, reducing the cold start underinflation penalty.



The video explains how an American picture frame manufacturing company is encouraging their employees to fill their vehicle tires with pure nitrogen. It also talks about the benefits of using pure nitrogen. Aside from the gas mileage aspects of nitrogen, the video shows how far back Detroit has fallen. When the nation has to count on picture frame manufacturers to promote fuel economy measures what does that say about Detroit's ability to survive in the future?

Diesel Energy Tax Credit

Under the right circumstances, the IRS can help you save on gas. The Feds have been offering tax incentives to increase fuel economy. One of the incentive programs is the Advanced Lean Burn Technology Vehicles credit. Here you will find a list of qualifying vehicles. So far they are all diesels from model year 2009. So if you have been considering buying a diesel car this could be you chance to do so and get a tax credit at the same time.

The IRS will only give out the money if you are the original buyer of the vehicle, so no buying used. Also the vehicle must be for your personal use and not for resale. The amount of the credit depends on the model you choose. Also the credit amount decreases as the automaker sells more and more of the vehicle. It drops to zero after the sale of 60,000 vehicles. So if you want a larger tax credit, it helps to buy sooner rather than later.

Why the "Lean Burn" in the tax credit title? It means that the engine operates with more air in the cylinder than is necessary to burn all the gas. There is extra air. This allows for higher compression ratios and lower airflow friction losses (or pumping loss) but produces NO_x pollutants. However, modern catalytic converter systems are capable of treating these. Perhaps in the next post we will talk about lean burn technology for saving on gas.

Want to Share a Zipcar?

The very best way to save on gas is not to drive. One way to cut back on driving is not to own a car. That is a pretty drastic way to save on gas though. What about the times when you need a car, or having one would be a lot more convenient? This is where car sharing programs come in. These programs are a step beyond carpooling, where you share your personal car because the idea is you don't have to own a car at all.

Zipcar is a car sharing program that lets you reserve a car for a time of your choosing. Could be a couple of hours to get some groceries or a couple of days to go on a business trip. You can pay on different plans. Their basic plan has you paying $50 a year as membership fee and then $7 an hour for car time, or $69 daily. The car time price includes gas and insurance. Zipcar is responsible for keeping the fleet in tip top mechanical shape.

Clearly you can save a lot of money on the price of a car this way. If you don't drive much, you can spend as little as hundreds of dollars a year reserving a Zipcar only when you really have to. The tens of thousands of dollars you could have spent on a car stays in your pocket. But does it help you save on gas? Gas is included in the reservation price of the Zipcar, so moneywise it is difficult to say. You have to separate out the insurance, maintenance, etc. costs. It also depends on the fluctuating price of gasoline.

In terms of amount of gasoline used, you will save on gas if the Zipcar of your choice is more fuel efficient than a car you would personally own. That is impossible to answer. But big savings would come from you driving less. Having your own car that you can just jump into without having to reserve time encourages you to make a lot of gas wasting small trips. Using a Zipcar will motivate you to plan your trips. Combining many small trips into one or walking or using public transport for some things can reduce the miles you drive. And reducing miles driven is the very best way to save on gas.

Electric Police

We have talked about specialized vehicles for specialized tasks before on Save on Gas. For example, families could use a Neighbourhood Electric Vehicle or NEV to run errands close to home. Picking up a couple of things at the grocery store is a perfect job for a NEV. In the United Kingdom, the police are thinking along similar lines. Police forces in the UK are introducing the Mitsubishi iMiEV (MiEV stands for Mitsubishi Innovative Electric Vehicle) for urban policing. The iMiEV has a top speed of about 80 miles per hour and a full charge gives it a range of around a 100 miles. Clearly this is not a highway patrol car, but it is a perfect vehicle for urban community policing. It has space for 4 passengers and normal police equipment. And it is a great way to save on gas.

The iMiEV can be charged anywhere you can find an electric socket, so the cops can refuel while parked in front of the donut shop. It is also quieter than a gasoline internal combustion engine, so they can sneak up on the bad guys in the still of night. In the UK there are strict limits on greenhouse gas emissions. The iMiEV, being electric, does not emit CO₂ while operating. That is one of the big selling points for the police, who must comply with the tough regulations.

The use of the iMiEV is a perfect example of getting better fuel economy by choosing the right vehicle for the job at hand.

Aptera : Electricity Meets Aerodynamics

The Aptera is a futuristic gas sipper brought forward into our time. It is available today. The Aptera combines extreme aerodynamics with efficient electric motors to use only 0.33 GPHM while delivering enough performance to do 0 to 60 in about 10 seconds. Top speed is 90 miles per hour. It has a range of 600 miles. Looking at the shape, you can see it is basically an airplane without the wings. Another secret to its very good gas mileage is its low weight. It uses lightweight but strong composites in its body panels giving it a weight about half that of the typical car.



The Aptera is a two seater and obviously has less cargo space than a Ford F150. But for many purposes, that is all you need anyway. One of the best pieces of news about the Aptera is the price tag. Unlike some electric futuristic gas sippers with price tags in the $100,000 range, the Aptera sells for around $30,000. Little by little, the gas sippers of the future are becoming today's reality.

Corvette vs Prius Gas Mileage Challenge

Imagine a future where instead of racing for speed we race for fuel economy. This video shows something like that. A Prius and a Corvette both run the same route on a normal highway. The highway crosses normal, somewhat hilly terrain and has curves. It is not a straight and flat highway. In other words it is what most people drive all the time. The two cars both top up their fuel tanks and then cover the same route to the same destination, where they top up their tanks again. The car adding the least gas at the second fill is the winner.

In the video the Prius wins, but the Corvette has a good showing. As the video points out, the Corvette has a streamlined shape with low drag coefficient. Note that the driver of the 'Vette is using hypermiling techniques, like taking corners as fast as possible (to avoid having to slow down and speed up again) and coasting down hills. The driver of the Prius takes no special measures to increase fuel economy. Hypermilers can do much better with a Prius than the gas mileage the video shows.

One thing the video shows is that fuel economy is not always directly opposed to other things you could look for in a car. In the case of the Corvette, both performance and fuel economy are helped by its low, streamlined shape and light weight. The high performance cornering characteristics of the 'Vette enable the tactic of taking corners at speed.



If you have a lazy weekend with nothing to do, why not organize a gas mileage challenge between you and a group of friends? Pick a start and a destination separated by a hundred miles or so. All the competitors top up at the start, drive exactly the same route and then top up again at the end. Lowest final fill wins. If you trust each other, you can even run the race different days and report back the final fill amount. Leave a comment here at Save on Gas if you do it!

Biodiesel Burning Demonstration

It is actually pretty easy to make your own biodiesel at home. We put up a video by the Mythbusters in which they did nothing more than filter used French fry oil. The result was a sort of "biodiesel" which they then used to fuel a normal diesel car. This video shows that if you do want to make biodiesel at home you don't have to worry much about safety. Biodiesel in liquid form is very difficult to get burning. But as you can see in the ending sequence of the video, when it is atomized into tiny droplets with a high surface area to volume ratio it does burn. That atomization coupled with the high pressures in the cylinders of a diesel engine is why it works to power your diesel vehicle.



If anyone has the inclination to try making their own biodiesel, I want to encourage you. There was a time when people where much more do it yourself oriented. Today a big percentage of the population depends on buying premade stuff in department stores. If you know how to make things yourself it gives you a better understanding of how the world and our economy works. You know that products don't just appear on shelves because you have seen what it takes to make them. Also you are much more independent. If you can do it yourself you can also find a lot of chances to save too. Doing it yourself will also develop skills that you will keep forever, possibly offering you opportunities to sell your services in the future. Spending a few hours trying out biodiesel production at home will benefit you way more than sitting in front of Today's Reality TV Show for that same time.

One Person Commuter Cars

Here is another vision of a gas sipping future. According to Rick Woodbury, inventor and developer of the Commuter Car 88% of all cars doing the daily haul in to work carry one person. That means that most of the road space in the morning and evening commutes is being taken up by empty seats. His solution is a small, one person electric vehicle that is not much larger than a big motorcycle. It has an energy usage equivalent to using 1.0 gallons per hundred miles (GPHM) which is good. It also has a price tag of $120,000 which is bad.

Although a one person vehicle selling at more than a hundred thousand is never going to become the commuting choice of the masses, the concept gives us a glimpse of what a fuel economy conscious future could look like. I believe that to get high fuel economy we will turn to a range of cheap vehicles each designed to perform one and only one function very efficiently. It is possible that we will see something like these single occupant electric cars widely used to get to and from work in the not so distant future.

Sideskirts Help Truckers Save on Gas

As you can imagine, truckers are interested in saving on gas. And if they save, it helps all of us. Higher transportation prices eventually work their way down the economic chain and raise the price of just about everything. The Delft University Aerospace Engineering department helped to develop a simple aerodynamic improvement to trucks to reduce their drag.

Many trucks have sideskirts, which are metal plates attached to the sides of trailers. Sideskirts block the space between the bottom of the trailer and the ground. They make in look like the truck almost rests on the road instead of having a large clear space underneath. The original purpose of sideskirts was for safety, to prevent cars jamming underneath the trailer in accidents. Delft University helped design aerodynamic sideskirts that shape the airflow. They reduce drag by keeping the airflow from going under the trailer.

Testing under controlled conditions on straight level roads revealed a 5% to 15% savings on fuel consumption. Long term real world operational tests by the transport company TNT found a 10% fuel savings. The sideskirts can be fitted to any truck. This one simple change can be deployed across the entire existing trucking fleet.

Delft also investigated the aerodynamic drag reduction possible by fitting a special "boat tail" to the back end of trucks. Although this offers further drag reduction giving another 10% to 15% fuel use reduction it is not practical for operations. Loading and unloading of cargo would be too difficult and the extra length added to the vehicle would make it unmanageable. However, the boat tail results could be used in a future where the transportation industry is rebuilt around fuel economy as priority number one.

Tesla Motors Plans to Widen Product Line

Tesla Motors is planning to develop an electric family sedan and a fleet minivan. Tesla Motors is the maker of the Roadster, an all electric lithium battery sports car. There are about 700 Roadsters in use today. Tesla will be using a $350 million Department of Energy loan to finance the development process.

Tesla Motors is a new company. It looks like we will need new blood to pioneer the frontiers of fuel economy ... the old established automakers have shown much less interest in the future. We will see how Tesla goes. Although their technology is interesting, they have until now very little market penetration. 700 vehicles is an engineering proof of concept but I doubt it is convincing for a marketing executive. The new models, including the family sedan or model S, are to be produced at an unspecified future date. It is not even clear that the factories that will make them are under construction.

Right now we are still enjoying pretty cheap gas. According to gasbuddy the national average is around $2.50 per gallon. I think we will see an explosion in interest towards electric vehicles the next time the price gets above $4.00 per gallon. And that $4.00 per gallon gas will return.