MPG / fuel efficiency question

**greekislandgirl** · 06-24-2010, 11:36 AM

Hi,

We're moving house, and I'm trying to figure out if it is cheaper for my husband and me to drive or take a train. Here's the situation:

- our car is a 2008 Mazda2 (small economy car, rated 4.9L/100km (48 MPG) highway)
- the distance is almost exactly 500 KM and it's all highway
- the reason for this trip is we are moving, and we are packing EVERYTHING into the car - it will be totally full
- since we will be coming off of a 7 hour ferry ride in the evening, IF we drive, we'll have to spend a night in a hotel
- the cheapest hotel room is about €50 / night
- gas costs €1.60 per Liter
- if we take the train, it's an OVERNIGHT train so no hotel
- the train costs €127 for two people and the car (the car travels as freight)

So I guess that our car, at 4.9L/100km and it's 500 km, it will need 24.5 Liters, at €1.60 / Liter that's €39.20 for gas.

Tolls are €12, and we have to add the hotel (say €50) so it comes to about €101 if we travel by car.

If we travel by train, it's €127.

The advantage of the train is that we get there faster; the advantage of the car is it's more comfortable, we don't have to sleep on a train (yuck) we can stop whenever we want. Since it appears cheaper, and since we're not in a big rush, I would prefer the car, although not enough to choose it if the train were cheaper....

But I was thinking, maybe the car would work out to be MORE expensive -

does anyone know if loading a car with a lot of stuff (especially a small economy car) would dramatically change fuel efficiency? NONE of it is furniture. It's just clothes, shoes, some books, linens, some kitchen stuff, small stuff. Full trunk and back seat, nothing on the roof.

Anyone have an idea about this?

**Greebo** · 06-24-2010, 11:42 AM

Adding weight to a car increases its mass, which increases the amount of force needed to change /maintain its velocity, which in turn increases the amount of fuel needed to make it go.

How MUCH depends on the total mass (think weight) added. It takes the same amount of energy to move 1000 pounds of lead as it does 1000 pounds of feathers - volume isn't a factor - weight is.

If you're only adding fairly light stuff, it is unlikely to make a significant difference. And as you said, there are more factors to consider than just cost.

**greekislandgirl** · 06-24-2010, 11:49 AM

I'm starting to think it's pretty significant weight-wise, the more I think about it. Most of what we have is clothes (not heavy) and books (heavy), and it's going to be totally packed in. But no furniture, mattress, or appliances.

There is something else that's worrying me... after we go the first 500 KM, we HAVE to drive another 300 KM because there's no train taking cars that goes there.

I'm concerned about wear-and-tear on the car... it's a small car... 800 KM absolutely packed to the brim vs. 300 KM...

I would rather err on the side of protecting the car than saving €20 so maybe the train tickets are the right investment?

**Greebo** · 06-24-2010, 11:52 AM

Originally Posted by greekislandgirl

I'm starting to think it's pretty significant weight-wise, the more I think about it. Most of what we have is clothes (not heavy) and books (heavy), and it's going to be totally packed in. But no furniture, mattress, or appliances.

There is something else that's worrying me... after we go the first 500 KM, we HAVE to drive another 300 KM because there's no train taking cars that goes there.

So if you take the train you have to unload and load up the car anyway? How will the car get there?

I'm concerned about wear-and-tear on the car... it's a small car... 800 KM absolutely packed to the brim vs. 300 KM...

Not a factor unless you fill the car with lead and try to drive it.

**greekislandgirl** · 06-24-2010, 11:54 AM

No, if we take the train, we just put the fully loaded car on the train and drive it off at the other end and keep driving. No loading/unloading required for that.

I'm relieved to hear that overloading the car isn't a big issue for wear and tear! Thanks

**Greebo** · 06-24-2010, 11:59 AM

Don't get me wrong - you CAN overload a vehicle - but some books and clothes aren't gonna overload it.

If you hooked up a trailer to it loaded with cinder blocks, and it was so heavy you needed full gas just to start moving -THAT would be overloading.

**lparker** · 06-24-2010, 01:32 PM

So you take the train and still have to drive 300km? So that's 127+80 euros not counting food and still may have a hotel stay. 500 km = about 300 miles...that's very drivable in one day.

I'd drive it.