fuel economy difference in cargo shipment

[hhtguy]

Currently, I have a project that researchs methods to save fuel, mainly the practicality of using existing cars on the road to help with logistics in a region. So assuming 40000 lbs of cargo need to be shipped from point A to B (100miles). One can either use a single truck to ship this via one trip, or alternatively, one can divide up the load and ship them via cars that are planned to go from A to B (like a carpool). Since the cars are already going from A to B in the first place, the fuel required is merely the additional fuel the car will use in carrying the cargo.

I know that a 10% increase in rolling friction (dependent on weight)results in roughly a 2% increase in fuel consumption for a typical car. Assuming the car gets 27 mpg and weighs 3200lb (typical), carrying 320lbs (10% increase in weight, so roughly 10% increase in rolling friction) will result in around 2% increase in fuel burn. At 27mpg, 100 miles will burn 3.7 gallons, so 2% of that is 0.074 gallon.

0.074 gallon is the additional fuel the car used in carrying 320lb for 100 miles.

40000/320 = 125, so we multiply 0.074 by 125 = 9.25 gallons, which is the fuel that 125 cars will use in carrying the total 40k lbs.

On the other hand, a semi will get loaded to the max with 40000lb and gets around 6 mpg. 100 miles will use up 16.7 gallons of fuel.

So the first method is significantly more efficient. If the cargo has less density, the difference will be more prevalent. I merely plugged in common values to arrive at my conclusion. This is assuming the car do not have to deviate from its course to reach the drop off point.

I would like to know if there are any good literatures and sources on the situation I've just talked about because I'd like to get some good sources to back my results up. Thanks

 

[IRstuff]

I think that you are neglecting factors that may completely overwhelm such a system. To wit,

> a single truck has a single start and possibly a single stop. If it is a single stop, then ALL of your cars need to go that same stop, regardless of whether it was really convenient or not. This adds to the cost and traffic congestion at both ends. If not, then a massive shipping and tracking system is required to plan how the product will be delivered to each of its final destinations.

> loading of cars is very manually intensive labor, compared to using forklifts to load a truck. Ditto for unloading. This adds significant amounts of labor cost.

> the more something is handled, the more likely it is sustain damage. Manual loading and unloading would statistically increase the amount of unusable product, also raising the cost.

> it's unlikely all 125 cars will all arrive and leave at the same time. This further increases the labor and holding costs, since both ends must now spend time waiting for each car to arrive to load and unload. Additional manpower and utility costs would be incurred.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[thruthefence]

Why not load the cars with the cargo, and load them (the cars) on a transporter?

 

[patprimmer]

TF

Such a system might actually be feasible for some long haul by loading semi trailers onto trains. It would reduce fuel usage and reduce double handling and poor point to point delivery typical of train transport if a loaded trailer could simply be driven on and off from the closest rail yard to the despatch/destination points.

hht

Do your own homework. We are not a free tutoring service.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[1gibson]

Operator costs such as: load/unload, driver time (you really think people are going to run these errands for free?) would more than negate any fuel savings. Not to mention handling risks/damage, tracking, and other concerns already mentioned. If the drivers are already employees, what about unions? Load/unload injury risks, loading dock traffic, or, moving product throug the front door of an office.

Ultimately, the intent of any fuel savings project is to reduce cost. Otherwise, the solution is bicycle messengers (0 fuel usage, ideal solution.)

"Good sources to back your results up."... I'd be careful with your terminology there, these are calculations, not results. Make sure you keep the logistics in perspective, and don't mix up calculations with conclusions/results. Also be careful with statements such as "the first method is significantly more efficient."Fuel efficient," arguable; what if the delivery truck happened to be going back and forth anyway? "Get the job done" efficient, I don't mean to be harsh but that is laughable.

If all you want to do is play a numbers game, I don't think anyone is going to object to your original post. If that's the case, feel free to use my bike messenger idea.

 

[rmw]

Let's see.....

I drive a vehicle that uses about 5 gallons of fuel to travel somewhere around 100 miles, loaded or not (22 mpg in winter without A/C).

And you are going to travel 125 cars that 100 miles on a grand total of 9.25 gallons?

Wow.... I better get one of those cars.

rmw

 

[pontiacjack]

Hmm... seems to beg the question; are we talking legal cargo?

 

[TonyDeRamo]

rmw,

the 9.25 gallons was the theoretical increase in fuel consumption related with a 10% increase in rolling friction.

None of this considers the increased fuel required to accelerate as well as the increased wear on brakes/clutch for hauling the added weight.

 

[SomptingGuy]

Are you also assuming that the route is flat and has no stop/start driving so that the increased weight only affects rolling resistance?

- Steve

 

[patprimmer]

Another obvious flaw in the calculations is that pick up and drop off points are never exactly on route. There is always some small deviation through a gate into a depot then stopping and starting a few times while checking in, presenting paperwork (which would be greatly duplicated vs a single large truck delivery) standing in cue idling or stop starting and moving into and out of a loading dock.

Also a larger depot with more docks would be required to accommodate the much higher traffic flow in that area.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[btrueblood]

And what's to stop the casual driver/delivery person from checking out the contents of the packages? Hmmm...deliver this expensive camera to its intended recipient and earn $.57, or drop by the local pawnshop and make $57?

 

[patprimmer]

BT

We have an expression here "at that price it must have fallen of the back of a truck" which implies the driver arranged for it to fall into hands not intended by the consignor. While the odds might change, I don't think theft of goods in transit is restricted to casual drivers.



Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[btrueblood]

Freight truck drivers with a habit of allowing 5-finger discounts eventually get caught, or else their parent company goes under from the weight of insurance claims. Both results end up with an unemployed driver, and the rap sheet may follow him. I'd think you'd see a rather sharp increase in the phenomenon when you first started the "Going My Way?" express shipping company...and how you'd police it is tough, since what's the downside to the blackballed casual delivery driver - he made $57 or got a new camera on his first trip, but gets blackballed - so what does he care if he doesn't get to participate on his next year's trip to Grandma's house. Meanwhile GMY Corp. is buried in thousands of claims, mountains of paperwork, and goes belly up.

 

[rmw]

Back in the days I owned trucks, I had one in a shop where in the next bay was a Frito Lay truck/trailer. The driver was giving away bags of Frito Lay products to everyone in the shop and stated that they were required to hand out the goodies for promotional purposes and would get in trouble if they didn't. We all loaded up with his help.

rmw

 

[SomptingGuy]

Do palletised freight networks (hub and spoke distribution model) exist outside of the UK? Or does the rest of the world (i.e. America) rely on point-to-point distribution?

- Steve

 

[patprimmer]

Australia certainly uses distribution hubs.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[IRstuff]

Palletized hubs are essentially the FedEx model, so they exist pretty much everywhere. Some of the largest warehouses around here are the central distribution hubs for Costco, Albertson's, etc. Likewise, the airlines have been running hub and spoke systems for decades.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[btrueblood]

Steve,

Most freight in the US goes via hub and spoke routing, but many carriers can and do plan more creative routes, where a given truck never actually stops in a depot, and the freight may never leave its original container/trailer until it hits its delivery dock. Even UPS and Fedex use a hub/spoke system, though their hubs are typically located near airports to support express shipments; they also ship along planned routes as above, and it seems to be random whether different freight will be routed through their hubs or not (based on watching the tracking progress online). At the same time, we can ship freight as far as Oregon and it goes essentially point to point; the carrier plans a local pickup route in Seattle, and the truck (once loaded) hauls down the interstate, dropping stuff en route. Our local UPS driver can/does drop things between us and the local hub - but I think he is smarter than the average brown truck driver. We also ship nearly full containers, and these essentially move from our dock to the shipping dock, as far away as Houston. Mind you, the container (trailer) may have 3 or 4 tractor changes from here to there, as it moves though the shipper's hubs en route. So...I think it's a mix.

 

[SomptingGuy]

I was thinking of companies like Pall-Ex, who only run the hubs and organise the collaboration of 100+ hauliers. They don't ship freight themselves, but allow those who do to collaborate in a cost-effective way.

- Steve

 

[dgallup]

I received a FedEx "ground" package at my home (in South Carolina) less than 24 hours after it left Anchorage Alaska. There were 3 stops at hubs/distribution centers in between. You got to love free shipping. How can you get more efficient than that?

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.