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I had to take a detour home today so my usual commute was swapped out for a highway drive for a few miles.

I found it incredibly difficult to get decent mpg. I'm not sure if it was simply all the traffic and the need to keep up or if my accelerator technique was all wrong. I've been doing ok on my regular roads to work (even taking into account two annoying hills). The car just felt "sticky" and didn't really want to drop down to lower rpms. Speeds weren't all that high (40-50 max), often more like 20-30mph if traffic was slowing. In the city at 20-30mph I'm happily getting decent mileage when the car is warmed up.

Once I was on my final leg home it was plain sailing. SoC was good the whole time. I'm wondering if the additional traffic just stopped me from doing any of the P&G, fake downshift or EVGlide techniques that I could use otherwise.

The difference was 35mpg on the highway run...50mpg for the country road segment. I'm wondering if I should be accelerating to a higher speed to coast more, rather than trying to micromanage the revs at the low end.

In any case, it further increased my hatred of rush-hour highway driving and makes me appreciate my 40-minute country commute even more :rolleyes: Wifey is away this weekend so I'm tempted to take it out for a spin and try a few miles on more open road at highway speed.

Car is a 2008 HCH-II.

Rush hour traffic is really terrible here; I live in the same state. What's the speed limit on the highway you were on?
It has also been very windy recently. I wonder if you were driving against a headwind?

Speed limit was 50mph I think but we mostly never had the chance to reach it :) I was heading into what would have been a headwind yesterday but I didn't think it was as bad today. My second segment would have been parallel to the wind. This was I84 heading east out of Hartford at 5:30 ish. Worst. Timing. Ever.

I feel your pain. Just came back from Long Island on a Friday evening, and we rarely got up to my usual highway speed of 55-60 along the entire route through NY and CT. I try to keep enough space between myself and the car in front of me so I don't have to brake much.
Your first instinct to use the secondary roads is a good one. That's my preferred method wherever possible.
It might be interesting if you tried the highway again sometime other than rush hour. The HCH usually does better than that on the highway. It likes secondary roads, too. Not so much the stop and go stuff.

The funny thing about it all is I'm complaining about "only" getting more than twice the MPG of my old car :D The drive is far more comfortable too.

It is surprising how quickly we forget what it once was! H

20-50 mph sounds like the sweet spot for the II, when I hit that kid of traffic during a commute my MPGs steadily increase. DWB, DWl, gliding and SAHM mode { http://www.cleanmpg.com/forums/archive/index.php/t-14295.html } all work if let the gap between you and the cars in front vary a significant amount so you never hit the extremes. Now if you're grinding to an occasional halt or frequently dipping below 10mph it's a different story, the II labors to get back to speed from those depths.

Did you accidentally select Sport Mode with the gear shifter? (I've done this more than once :o).

Wind from the side might be great for sailing, but is a sneaky killer of MPG: upsets aerodynamic stability, necessitates more steering inputs and increases tire patch friction. Rough pavement has much the same effect.

The S mode crossed my mind too! I haven't yet tried that...there was certainly plenty of grinding and laboring in that run though!

I had to take a detour home today so my usual commute was swapped out for a highway drive for a few miles.

I found it incredibly difficult to get decent mpg. I'm not sure if it was simply all the traffic and the need to keep up or if my accelerator technique was all wrong. I've been doing ok on my regular roads to work (even taking into account two annoying hills). The car just felt "sticky" and didn't really want to drop down to lower rpms. Speeds weren't all that high (40-50 max), often more like 20-30mph if traffic was slowing. In the city at 20-30mph I'm happily getting decent mileage when the car is warmed up.

Once I was on my final leg home it was plain sailing. SoC was good the whole time. I'm wondering if the additional traffic just stopped me from doing any of the P&G, fake downshift or EVGlide techniques that I could use otherwise.

The difference was 35mpg on the highway run...50mpg for the country road segment. I'm wondering if I should be accelerating to a higher speed to coast more, rather than trying to micromanage the revs at the low end.

In any case, it further increased my hatred of rush-hour highway driving and makes me appreciate my 40-minute country commute even more :rolleyes: Wifey is away this weekend so I'm tempted to take it out for a spin and try a few miles on more open road at highway speed.

Car is a 2008 HCH-II.


It's very difficult to achieve high energy efficiency during rush
hour because of the speed and the traffic. Drafting/slipstreaming
and Driving With Load (DWL) are the best hypermiling techniques
for driving faster than 55 mph (super highway). However, they can
become increasingly difficult to do as traffic gets more congested,
other drivers become more aggressive, and the overall traffic speeds
gets faster. P&G and EV modes are often not sustainable at speeds
over 55 mph.

Before you go onto they highway, make sure your tire pressure
is set to about 2 to 5 psi over the manufacturer's recommended setting.
+2 psi is for aggressive rush hour traffic while +5psi is for long distance
non aggressive turnpike hi speed traffic. 2 psi + recommended psi
will likely be more energy efficient for sudden and constant application
of the accelerator. My experience and others on prius chat has
been that as tires pressures are inflated at higher levels (e.g.
+7psi) highway FE drops ( my currently theory is that the
transfer of energy is less efficient because tire deformation decreases
as tire rigidity decreases with overinflation, the tire deformation
is necessary to maintain tread road traction during high speed
accleration sessions).

I ran the same route today and noticed that (A) it has a slight but steady UPHILL incline, which I hadn't noticed with all the traffic around me and (B) I do need more practice getting used to the throttle/rpm dance at high speeds. I also got to see how poor Cruise Control is at maintaining good MPG compared to proper manual control :o)

An interesting segment, so I'm hoping to do even better next time I get to go on the highway.

My tires actually were already at near-sidewall from the dealer, which was nice. Rated as 44, doorframe says 32, I got them at 40 (according to my pump - I may double check at a service station). I wonder if that's why I do feel they do better on the slower roads. Dunno.

I personally have seen nothing but across the board FE improvements in my vehicles when raising the tire pressure. I can't think of anything that would cause lower FE at highway speeds after raising the tire pressure.

Been slowly upping mine to the current 55psi...no objective proof, but it seems to roll/glide easier and after closely inspecting the tires this weekend (laying on the ground: finally bought the wheel well inserts and removed my rear splash guards yesterday...the fronts last year) I can say my tire ware is even across the tread.

.......when I hit that kid ..... during a commute my MPGs steadily increase.

Yes, stopping for peds will screw with your mpg, that's for sure. ha ha ha
Sometimes, typing errors are funny in very black ways.

never noticed the typo...black ways indeed that you just did: I hit the legs and breast of a red tailed hawk with the top part of my windshield and roof going 60 in a 70psl yesterday...it kept flying, but had to be hurt :(. A couple of small feathers stuck in the plastic molding above the windshield and a big streak through the fresh wax on the roof.

I battle that same sort of traffic on my daily commute and have gotten the hang of it. I get about 40 mpg for that highway stretch. I have a 2011 Honda FIT AT and the key seems to be to use adequate buffers so that you "filter out" the speed up/slow down cycle that everyone else is doing so you are driving more or less a constant speed and don't have to touch the brakes. I also use pulse and glide (in N) to get the most out of the little hills etc. It takes some practice and a lot of anticipation and I am still learning. You also have to get comfortable with letting a big gap build up in front of you knowing that they line will slow down and you will catch back up. Some people will pull in front of you but not as many as you might think, even is super aggressive Boston traffic that I drive in. I would guess with some practice you would be able to beat my ave in your HCH.