Short Trip Myth

You have several things wrong with your statements.

1) Your short trip of 5 miles was during a longer trip. So when you take your average of your 210 miles and say you used 4 gallons that makes your mpg roughly 50 mpg. Then you take this 50 mpg and say that someone driving 5 miles would only use 1/10 of a gallon. This is wrong. This only works if you actually average 50 mpg for those first five miles. So if someone drives 5 miles from a cold start they may struggle to reach 50mpg depending on where they are driving city vs highway. It might be closer to 35-40 mpg for those 5 miles. This is no myth. If you constantly make short trips from cold starts, your engine needs to warm up every time hence the lower mpg.

2) You say that your friend in a jeep uses only "maybe" half a gallon of fuel and uses it to drive locally. How do you figure? If the jeep can average 20 mpg then using .5 gallons means he only drove 10 miles for the day. This jeep would also suffer from a cold start and get lower mpg while his jeep warms up. I'm sure your friend drives more than 10 miles a day. Besides with a cold start that jeep might only average 15 mpg during the 10 miles while it warms up and then he have used .5 gallons driving only 7.5 miles.

3) You say your prius consumes a gallon a day. This means you drive roughly 50 miles a day. So your friend who drives only maybe 10 miles is greener than you who drove 50? I don't think so.

4) No SUV is going to be greener than the prius. Not for the immediate future at least.

5) Being green, when talking about cars, means that you use energy, namely gasoline, in the most efficient manner to move you around to where you want to go. If you need to go 50 miles what's the best way of getting there? In a jeep or prius? Obviously the prius because you only use 1 gallon while that jeep would use about 2.5 gallons. Almost no one can live just by driving 10 miles a day unless they live a block from work and a supermarket. In this case that person wouldn't be green because they could simply walk to work if they are that close.

 

That is true about living in the apartment vs huge house. This is a different discussion though.

You were talking about a short trip and then mention being green then you discuss mpg and gallons used.

This is why I said when talking about cars being green means using the energy efficiently. Green in the broader sense would mean picking renewable energy sources, locally grown produce.....and on and on. Driving habits are a small part of the being green picture. BUT if you don't have the option of using used vegetable oil to power your car or using solar power or an all electric car then using a gas car is your next choice. An all electric car is more expensive as well as a hydrogen car. A solar power car is impractical in city driving.

Then you have to consider where the materials came from to make your prius or jeep. How much fuel was used in getting it on the tanker to ship to the US if it was made outside. How much fuel did it cost to ship your car via truck to your dealership....and on and on.

Without getting into those kinds of discussions, a prius is greener than a jeep based on gas used to move you from point A to point B. Besides, a person that is trying to be "green" would never choose a jeep or suv because they are inefficient and expensive. They would choose a small efficient car like the prius c which is smaller, lighter, and more efficient in the city than the regular prius. But then we have the issue of the batteries that the prius uses.....see this is a never ending discussion.

To be greener, a person would ride a bicycle instead of choosing a car. A lot less energy to make a bike.

It is in our lifestyle choice that we choose to drive cars for convenience.

That being said. There is no myth about the short trip. It is always true that during a short trip you will have lower mpg because of the warm up and because accelerating and stopping at lights and stops signs has a bigger effect during those few miles. Once you get on a road where you can cruise then the mpg starts climbing. You can cheat a little by doing your short trips after the car has warmed up from a previous drive but the same still applies. The stops and accelerations impact your mpg more until you can start cruising.

 

This is the main part of your post

"Short trips will hurt your MPG. To me, this statement is really meaningless since we all make short trips every time we get into our cars."

To this statement I don't know why you say it's meaningless if it is true. Short trips WILL hurt your mpg.

Then you mention if you are trying to be green....This has nothing to do with whether short trips will hurt your mpg or not. They are completely different topics. If you wanted to talk about being green and a prius vs suv or the carbon footprint of the prius vs others then title your thread something else and maybe place it in a different forum than prius fuel economy.

 

You are now talking about different things. It's is only a short trip if you stop after the 5 miles. You are taking this out of context. Those 5 miles were part of a trip that was 50 miles. Take a look at your mpg when you get to 5 miles and tell me it's the same when you finish the 50 miles. If you take a short trip to the mall that was 5 miles away, do whatever for a couple hours then come home in a 5 mile trip then you just made 2 short trips. Your mpg for those trips will no doubt be low. So how can it be meaningless if the short trips do hurt your mpg?

You can't say that the first 5 miles of a 50 mile trip is a short trip because you didn't stop. It wasn't a trip.

What you are probably thinking, but just can't find the words for, is that the first 5 miles of a trip are countered by the rest of your trip until you get to where you are going because your car has warmed up and you are able to maintain speed.

This though doesn't change the fact that short trips hurt your mpg.

 

Here you go Dan. I had to make a short trip to the post office today. There and back, didn't have to turn off the car because of the drive through box. Tell me a short trip doesn't affect your gas mileage. I had an overall of 59mpg and after the trip I have 57mpg.

 

You keep coming back to being green. Why? Not every prius driver aims to be green.

Now you say the myth is, "short trips are worst than the long ones" and in your first post you say, "Short trips will hurt your MPG". So what's the myth?

 

OK, here's my take on it.
We often have the choice of making a multi-stop errand trip or multiple shorter errand trips to accomplish the same thing.

The multiple shorter trips are far less green (even if they add up to the same miles covered) because of the repeated warmup cycles.

Plan your errands combine them. Moreover, if practical, make the longest leg of the multi-stop trip the longest so that the car has less warming up to do with the subsequent legs.

Why am I feeding this troll? Can someone answer me that?

 

Aren't you guys sore from banging your head against the wall yet? :Lmao:

Sometimes, there are some people who cannot be convinced, no matter how much logic and reason you throw at them.

SCH-I535

 

Bob,"Uh honey, the gas gauge is getting a little low."

Wife,"Uh Oh, why didn't you fill-up the car?" as she accelerates.

Bob,"Why are we going faster?"

Wife,"I want to reach a gas station before I run out of gas."

Still married after 36 years . . . and counting.

Bob Wilson

 

me thinks me smells a troll?

 

It's always fascinating to see someone attempt to bring about new discussion by presenting something already well proven in a new way.

Antagonists do that to raise doubt and prevent conclusions from being drawn. They enjoy the ongoing exchanges, but their polarized views and credibility attacks make it pretty easy to see intent. Newbies are a different matter. You don't know if they are simply poorly informed, don't have the background to follow the technical detail, or just feel the need to prove something. We do our best to get the facts out and hope for the best.

In this case, the "Short Trip" problem has always been the efficiency penalty caused by the first few minutes of driving, due to the engine warming up. It meant a brief drive somewhere, like just a few blocks to the local store, would result in really low MPG. The only way to avoid that was doing short trips while the engine was still hot. Of course, with the availability of a plug-in model, those nearby errands can be run with just electricity.

In other words, there is no myth.

 

How can you agree that there is a short trip penalty, yet claim in your thread title that it is a myth?

If it exists, then it is not a myth. Are we clear yet?

SCH-I535