New Year's Resolution for 2008: 60MPG at 60MPH

Kizzy · 01-01-2008, 01:33 AM

Reading through various threads on highway mileage, it seems that 60MPG at 60MPH is somewhat of a common benchmark for the Prius. But my question is -- how!?

I've gotten very good at the pulse and glide technique (below 41 MPH) on surface streets, and can often obtain approx. 55-60 MPG during local city driving, sometimes even nearer to 65 MPG on trips late at night when there is little traffic and I can time the lights just right.

But when it comes to highway driving, my MPG's suffer. Traveling at 60-65 MPH (which basically qualifies me for the slow lane here in Southern California), my fuel economy typically drops to around 45-47 MPG, even on relatively flat road. Sure, it's pretty good compared to a conventional car, and more or less what the EPA estimates, but still considerably lower than the typical numbers I'm seeing here on PC.

So, what is the best trick for obtaining 50+ MPG's on the highway, and approaching the 60MPG @ 60MPH level? Should I use cruise control? The pulse and glide techniques that work on city driving don't seem to work at the higher speeds, since the ICE needs to be constantly on. Is there a sweet spot for freeway speeds, as there is for city driving? Can anyone give me a basic primer on how to get my highway MPG's up?

Much appreciated! And Happy New Year.

drees · 01-01-2008, 03:07 AM

Happy New Year!

At a constant 65 mph, you should be able to get a bit over 50 mpg. What are your tire pressures?

To get 60 mpg on the highway, I think your only hope is to slow down to 55 mph unless you can figure out how to significantly reduce the drag of the Prius even more.

JimboK · 01-01-2008, 09:03 AM

On terrain that's level or nearly so, cruise control is probably your best bet.

Things change when hills start creeping in. CC is very aggressive in trying to maintain speed, and will push engine RPM into inefficiently high ranges on moderate or steep hills.

See this for a comparison of CC with a method using manual pedal control on a highway with gentle hills. You'll see I came close to 60@60. Within the writeup are links to other threads and papers describing other techniques. In particular, warp stealth may be your best bet for hills; Hobbit has reported 63@63 using it in warm weather.

patsparks · 01-01-2008, 09:21 AM

I get about 45 at about 70mph, i'm happy with that. Gives me a range of about 800km or 500 miles on a 45 litre tank. My Camry had a range of 700km from 60 litres so i'm happy. You know the Prius is no good on the highway!

01-01-2008, 01:33 AM	#1
Kizzy Member Join Date: Dec 2007 Location: Los Angeles Posts: 40 My Car: 2008 Prius Package: #2 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	New Year's Resolution for 2008: 60MPG at 60MPH - But How?! Reading through various threads on highway mileage, it seems that 60MPG at 60MPH is somewhat of a common benchmark for the Prius. But my question is -- how!? I've gotten very good at the pulse and glide technique (below 41 MPH) on surface streets, and can often obtain approx. 55-60 MPG during local city driving, sometimes even nearer to 65 MPG on trips late at night when there is little traffic and I can time the lights just right. But when it comes to highway driving, my MPG's suffer. Traveling at 60-65 MPH (which basically qualifies me for the slow lane here in Southern California), my fuel economy typically drops to around 45-47 MPG, even on relatively flat road. Sure, it's pretty good compared to a conventional car, and more or less what the EPA estimates, but still considerably lower than the typical numbers I'm seeing here on PC. So, what is the best trick for obtaining 50+ MPG's on the highway, and approaching the 60MPG @ 60MPH level? Should I use cruise control? The pulse and glide techniques that work on city driving don't seem to work at the higher speeds, since the ICE needs to be constantly on. Is there a sweet spot for freeway speeds, as there is for city driving? Can anyone give me a basic primer on how to get my highway MPG's up? Much appreciated! And Happy New Year. Last edited by Kizzy; 01-01-2008 at 01:36 AM.

01-01-2008, 03:07 AM	#2
drees Senior Member Join Date: Oct 2007 Location: San Diego, CA Posts: 327 My Car: 2008 Prius Package: #2 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Re: New Year's Resolution for 2008: 60MPG at 60MPH - But How?! Happy New Year! At a constant 65 mph, you should be able to get a bit over 50 mpg. What are your tire pressures? To get 60 mpg on the highway, I think your only hope is to slow down to 55 mph unless you can figure out how to significantly reduce the drag of the Prius even more.

01-01-2008, 09:03 AM	#3
JimboK One owner, low mileage Join Date: May 2006 Location: Chesterfield, VA Posts: 1,902 My Car: 2005 Prius Package: #2 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 2	Re: New Year's Resolution for 2008: 60MPG at 60MPH - But How?! On terrain that's level or nearly so, cruise control is probably your best bet. Things change when hills start creeping in. CC is very aggressive in trying to maintain speed, and will push engine RPM into inefficiently high ranges on moderate or steep hills. See this for a comparison of CC with a method using manual pedal control on a highway with gentle hills. You'll see I came close to 60@60. Within the writeup are links to other threads and papers describing other techniques. In particular, warp stealth may be your best bet for hills; Hobbit has reported 63@63 using it in warm weather. __________________ Jim Lifetime fuel mileage: After learning how to hypermile: Click here for car details.

01-01-2008, 09:21 AM	#4
patsparks Uneducated bird-brain Aussie Join Date: Jul 2007 Location: Adelaide South Australia Posts: 4,438 My Car: 2004 Prius Package: Base Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 12	Re: New Year's Resolution for 2008: 60MPG at 60MPH - But How?! I get about 45 at about 70mph, i'm happy with that. Gives me a range of about 800km or 500 miles on a 45 litre tank. My Camry had a range of 700km from 60 litres so i'm happy. You know the Prius is no good on the highway!