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The cost of being lazy: Snow Haulin’ Edition

December 16, 2010

Pulling into work this morning, another vehicle in the parking lot caught my eye.

It’s not uncommon to see snow… though 5 days ago there was a blizzard that ranked reasonably high in the record books, dropping somewhere in the 16-18 inches of snow range.  However, it is uncommon to see someone carting around a truckload of snow.  At least I hope it’s uncommon, because seriously, even if this guy* loves snow, check out the background of the picture… we are not for want of the stuff.

Still, this got the gears turning.  I make it a point to rid my car of snow before driving to reduce weight, lower wind resistance, and for general safe operation.  I wondered a bit about what this load of snow, and the related lack of drive to just drop the tail gate and shovel it out, might be costing this guy.

The quantity (volume) of snow matters.  As you can see in the above image, there is some snow on the rear bumper, some snow is piled higher than the bed walls, and snow levels near the sides is slightly lower than the bed depth.  With a better in-person view, I’d estimate the total volume to be slightly greater than the bed, so we’ll round up.  The approximate specs for the truck bed are 74″ long by 57″ wide by 18″ deep.  This gives us just shy of 44 cubic feet which is approximately 1.3 cubic meters for calculations.

truck bed

But volume tells us little since snow is fluffy ice crystals with a density that varies based on how recent it snowed, how cold it is, wind/drift factors, and depth (further reading if you’re interested).  Rather than try to estimate the density, I decide to back calculate it based on a “Snow Water Equivalent.”  Basically, I took two empty cups, carefully filled them up with snow from the truck bed (one from the top, one from lower down, taking care to treat it like flour and not to pack it in).  I then let these melt.  Water has a density of 1000 kg (2205 lbs) per cubic meter.  So when the volume of water averaged out to be 25% of the original snow volume in the cups, I could calculate that the snow’s density was 25% of water’s, or 250 kg (551 lbs) per cubic meter.  Multiply this density by the 1.25 cubic meters in the bed and you get that this guy was carrying around an extra 312.5 kg or 689 lbs!

A quick bit of research on Toyota’s website (assuming this was about a 2000 Tacoma) and some searching through truck forums and efficient vehicle operation guides, I came up with 20 MPG for this truck and a typical reduction of 2% or 0.4 MPG per 100 lbs payload.  The result would be about a 2.5 MPG reduction from the snow.  If this vehicle was driven the average 33 miles per day, his fuel use increased from 1.65 gal to 1.89.  At $3 per gallon, that’s $0.72 per day, which is… underwhelming.  But it’s been 5 days since it snowed, so he’s likely to just keep on truckin’.  The result will be  $5.04 per week, $21.9 per month, and somewhere in the range of $75 if he does nothing about this all winter.

Of course, it’s possible that his snow is better than all the rest of the snow (quick calculation suggest the Twin Cities metro area alone received 16,579,260,720,000 lbs of the stuff).  So maybe it’s worth it to him.

 

Note: Truck bed wind resistance changes depending on if the tailgate is up, down, removed, replaced with mesh, or if there is a cover on the bed.  This snow might act slightly as a Tonneau covers, which are purported to help lower wind resistance and improve gas mileage slightly (experiences from the forums varied).  However, with the rough surface of the snow and the fact a cover would weigh less than 15% of this snow’s weight, I’m going to disregard any benefits along these lines as negligible.

2nd Note: I apologize for the puns throughout this post.

*I did observed that it was in fact a male operator of this vehicle

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From → MATH, random musing

5 Comments
  1. tailgate up, no cover is the most fuel efficient method. what happens is a bubble of circulating air forms behind the cab and creates a low-drag shape.

    structurally speaking, the tailgate should always be up as that is how the car is designed to handle forces in the case of an accident.

    on that note, hauling around 700lbs of snow also will increase the likelihood of an accident due to the increased stopping distance, not to mention the increased likelihood that another driver would careen into a pole while thinking “….the hell is all that snow in th-“

  2. Mary permalink

    Either your math is a little fuzzy or I’m missing something $0.72/day would be about $21.60/month, not $151.20. Looks like you multiplied the weekly amount by 30 instead of the daily amount.

    • Well, you see, there’s a factor in there when you go from a week to a month… and then there’s leap years… and time and space are curved…

      Yeah yeah, I fixed it.

      • Mary permalink

        Ha, well you know that math isn’t my strong suit so I wasn’t sure…

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