Does a passenger greatly reduce overall MPG's?

Soylent · 08-30-2006, 09:30 AM

Does a passenger greatly reduce overall MPG's? Obviously there will be a difference between a child and an adult, but I would assume that having a passenger greatly reduced the MPG, since the car has to haul more weight. Has anyone tested the same run with a passenger, and then without a passenger?

TheForce · 08-30-2006, 09:46 AM

I have and it does reduce it by a few MPG. Not much but I can see a difference.

**efusco** · 08-30-2006, 09:50 AM

Guess it depends upon your definition of 'greatly'. But overall it doesn't make much impact.

Using Wayne Brown's THSII simulator:
80 degrees, Driver + cargo weight 250 lbs and a few other things of lesser significance but balanced on all other measures.

No Passenger @ 35mph: 87.5 mpg
185 lb passenger @ 35mph: 85.8 mpg

No px @ 55mph: 62.6 mpg
185lb px @ 55mph: 61.6 mpg

No px @ 75mph: 47.7 mpg
185 lb px @75 mph: 47.1 mpg

These are some ideal conditions number so don't freak if they don't seem realistic, but they give a frame for comparison.

eagle33199 · 08-30-2006, 10:42 AM

If you ask me, the passenger effects the MPG by more than just their weight would warrent... It's the constant talking that does it, distracting you from your driving so you don't get optimal MPG's.

My little sis was just in town visiting this past weekend. when i picked her up at the airport, i was sitting at 54 MPG. when i dropped her off, it had dropped down to 48 MPG.

Soylent · 08-30-2006, 11:08 AM

<div class='quotetop'>QUOTE(eagle33199 @ Aug 30 2006, 10:42 AM) [snapback]311566[/snapback]</div>

Quote:

If you ask me, the passenger effects the MPG by more than just their weight would warrent... It's the constant talking that does it, distracting you from your driving so you don't get optimal MPG's.

My little sis was just in town visiting this past weekend. when i picked her up at the airport, i was sitting at 54 MPG. when i dropped her off, it had dropped down to 48 MPG.
[/b]

That's funny, you're right about that! And not to mention you'll be showing off, too.

DaveinOlyWA · 08-30-2006, 11:23 AM

additional passengers do make a difference. i have tracked a certain trip made alone (170 lbs) and with 3 others in the car est weight (140, 160, and 120. only the 160 is for sure, the other two are females and...well, lets not get into that) and the difference ranges as high as 4 mpg.

i think some of the difference can be extra wind drag for windows that would not normally be open if i were alone in the car. with vents up front, i can usually find a setting that is comfortable (and quieter) than cracking a window. with people in the back, someone usually opens a window.

i will say that in case of A?C usage, the extra weight puts a much bigger hit on the MPG's than normal

nerfer · 08-30-2006, 11:43 AM

<div class='quotetop'>QUOTE(Soylent @ Aug 30 2006, 08:30 AM) [snapback]311540[/snapback]</div>

Quote:

Does a passenger greatly reduce overall MPG's? Obviously there will be a difference between a child and an adult, but I would assume that having a passenger greatly reduced the MPG, since the car has to haul more weight. Has anyone tested the same run with a passenger, and then without a passenger?
[/b]

The more important thing is people miles per gallon, not vehicle miles. If you didn't have the person in your car, would they be driving an additional vehicle, one that gets maybe 20 mpg, sucking up fuel resources, adding to gridlock and polluting the air?
Even if two Prii owners carpool, then two people go 50 mpg = 100 people-miles per gallon. If they drive separately, but each gets 55 mpg, then it's just 55 people-miles per gallon, and almost twice as much gas is used.

qbee42 · 08-30-2006, 12:36 PM

<div class='quotetop'>QUOTE(Soylent @ Aug 30 2006, 09:30 AM) [snapback]311540[/snapback]</div>

Quote:

Does a passenger greatly reduce overall MPG's? Obviously there will be a difference between a child and an adult, but I would assume that having a passenger greatly reduced the MPG, since the car has to haul more weight. Has anyone tested the same run with a passenger, and then without a passenger?
[/b]

Depends on their size and how you carry them. Inside causes the smallest change. On the roof I find you do better if you orient your passenger the long way - less drag. Head first reduces nose drag, but this varies widely by individual. Dragging behind has the least wind drag for an external passenger, but then you get all of the friction. The good news is that the friction drops off over a fairly short distance.

Tom

adgo82 · 08-30-2006, 12:44 PM

When I pick up slugs I see about a 2mpg drop, which makes me mad :P I am trying to reach 60mpg hehe I was on 58mpg and now I am down to 56mpg. Oh well

Beryl Octet · 08-30-2006, 01:25 PM

<div class='quotetop'>QUOTE(Soylent @ Aug 30 2006, 09:30 AM) [snapback]311540[/snapback]</div>

Quote:

Does a passenger greatly reduce overall MPG's? Obviously there will be a difference between a child and an adult, but I would assume that having a passenger greatly reduced the MPG, since the car has to haul more weight. Has anyone tested the same run with a passenger, and then without a passenger?
[/b]

It probably hurts a small amount, but my passenger gets mad when I make them take their own car when we are going out to eat or shop.

08-30-2006, 09:50 AM	#3
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 14,018 My Car: 2004 Prius Package: #9 Nominated 1 Time in 1 Post TOTM Awards: 0 Friends: 23	Guess it depends upon your definition of 'greatly'. But overall it doesn't make much impact. Using Wayne Brown's THSII simulator: 80 degrees, Driver + cargo weight 250 lbs and a few other things of lesser significance but balanced on all other measures. No Passenger @ 35mph: 87.5 mpg 185 lb passenger @ 35mph: 85.8 mpg No px @ 55mph: 62.6 mpg 185lb px @ 55mph: 61.6 mpg No px @ 75mph: 47.7 mpg 185 lb px @75 mph: 47.1 mpg These are some ideal conditions number so don't freak if they don't seem realistic, but they give a frame for comparison. __________________ Evan E. Fusco, MD Seaside 04BC9/OEM EVb/NAV & auto-BT/XM Radio, CAN-View, Shark Fin, BT Stiff. Plate, Skid Plate & Strut Support

08-30-2006, 11:23 AM	#6
DaveinOlyWA Opps !! I Did it Again!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 9,521 My Car: 2006 Prius Package: #4 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 4	additional passengers do make a difference. i have tracked a certain trip made alone (170 lbs) and with 3 others in the car est weight (140, 160, and 120. only the 160 is for sure, the other two are females and...well, lets not get into that) and the difference ranges as high as 4 mpg. i think some of the difference can be extra wind drag for windows that would not normally be open if i were alone in the car. with vents up front, i can usually find a setting that is comfortable (and quieter) than cracking a window. with people in the back, someone usually opens a window. i will say that in case of A?C usage, the extra weight puts a much bigger hit on the MPG's than normal __________________ My 2006: Last tank 463.1 miles @49.2 pump (49.4 computer) 4.22 cpm winter mpg 50.70 summer mpg 54.59 lifetime: 33,038.3 miles 52.79 mpg pump (54.04 mpg computer) 5.74 cpm My 2007 Zenn Driven 5849 miles, 2.00 cpm/ 105 mpg (at $2.05/gal), 4.04 miles/ Kwh Savings over my Prius $300.79 The Corolla...567.79 The REAL SAVINGS from not driving Corolla 657.39 +Prius= 958.18 (excludes maintenance costs...would be unfair to ICE vehicles) My Plate: DUALPWR (Dual Power)

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08-30-2006, 09:30 AM	#1
Soylent Senior Member Join Date: May 2006 Posts: 245 My Car: 2006 Prius Package: #3 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Does a passenger greatly reduce overall MPG's? Obviously there will be a difference between a child and an adult, but I would assume that having a passenger greatly reduced the MPG, since the car has to haul more weight. Has anyone tested the same run with a passenger, and then without a passenger?

08-30-2006, 09:46 AM	#2
TheForce I Plug-In My Prius Join Date: May 2005 Location: Wheelersburg, Ohio Posts: 2,101 My Car: 2006 Prius Package: #7 Nominated 7 Times in 2 Posts TOTM Awards: 0 Friends: 17	I have and it does reduce it by a few MPG. Not much but I can see a difference.

08-30-2006, 10:42 AM	#4
eagle33199 Platinum Member Join Date: Mar 2006 Location: Minnesota Posts: 3,594 My Car: 2006 Prius Package: #7 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	If you ask me, the passenger effects the MPG by more than just their weight would warrent... It's the constant talking that does it, distracting you from your driving so you don't get optimal MPG's. My little sis was just in town visiting this past weekend. when i picked her up at the airport, i was sitting at 54 MPG. when i dropped her off, it had dropped down to 48 MPG.

08-30-2006, 12:44 PM	#9
adgo82 Join Date: Aug 2006 Posts: 34 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	When I pick up slugs I see about a 2mpg drop, which makes me mad :P I am trying to reach 60mpg hehe I was on 58mpg and now I am down to 56mpg. Oh well