Anyone think road conditions and the material it's made of effects mileage much? In my recent trip to TX from FL I went through some pretty back-woodsy country and I noticed on some roads I did all I could to keep my FCD above 75 (Insight goes from 0-150mpg on the FCD for those unfamiliar). It just wouldn't stay above it even when I going at speeds I KNEW should be producing 100mpg on the display. Sure enough, when I got to another "patch" of road that started in another county my mileage shot up.

Anyone ever notice this? Could be one more reason some people just can't get the stellar FE numbers others get.

'00 Insight "Wazabi" -75,000+ miles
'03 Toyota Matrix - 81,000+ miles
'03 HCH-CVT-OSBM-41,000+ miles (retired 04-10-06)
"I'm very secure with my little Insight, no Prius envy here."

I notice this too - all the time. On flat, smooth pavement my car will hold 50 MPH with 80 MPG on the FCD. When the pavement is rough or it's a side road, I have a hard time holding 50 or 60 even if it's level. I'd definitely agree with your assertion.

*** Retired after 65,000 outstanding miles ***

On a totally unrelated subject (well, okay maybe marginally related), how about that rubberized asphalt? Man oh man, night and day! Most of the beltway around Phoenix has been repaved with the stuff. It's so nice to be travelling down the highway and it being near absolute quiet in the HAH. But then, as soon as you hit the old concrete stuff, whoa! What a difference.

So, back on subject. Would the rubberized asphalt create more resistance? And reduce overall FE?

<Best Tank Economy!><Best Tank Endurance!>



The new mileage database... well, it sucks! Not to mention the fact that my requests for help from the site owner have gone unanswered. So, I won't be tracking mileage on this site anymore. Many others have moved on as well, for similar reasons. There are several good sites out there to choose from. The two I picked are fueleconomy.gov and myhybridcar.com. But, check out the many alternatives for yourself, and see if another would suit your needs better.

my guess is that smooth concrete is best- hardest so the least energy is absorbed into the roadway- and so louder too. Aspalt is stickier and not completely solid surface- gaps between the fill material. And we all know it gets gooey especially once it warms up- it feels like you're plowing through it sometimes!

But it is nice to drive on fresh asphalt- so smooth and quiet! As long as its not too fresh and leaving streaks on my lower panels.

Absolutely. I think it makes a very significant difference. I have roads here that that old paved-gravelly stuff, and my HCH labors; but on the newer, very smooth surfaces, it's like I'm gliding right along.

Makes you wonder: if MPG was effected by 5%, or even 10%, what would the fuel savings be if they just resurfaced roads with a smoother substance?

Absolutely. One one of the highways that I drive on the way to work, the construction company for some stupid reason suddenly switched from concrete to CHIP SEALED asphalt, of all things, right in the middle of the area under construction. Once I leave the concrete to the crap asphalt, I can literally see the instantaneous mileage bar drop.

A long stretch of a county road was repaved recently. On my daily commute in the morning, this stretch is a long downhill followed by a flat, slightly uphill section, followed by a sharp, short downhill. Before the road was repaved, I could never imagine coasting from the top of the first hill to the bottom of the second, as the middle part would strip too much speed away. Now, after repaving, I can coast through the entire section.

I think the road surface condition is a significant factor in mileage results.

-Charlie...

Of course the road surface has a significant effect on FE. Just imagine driving for a long stretch on a brick road. Unfortunately, bureaucrats in a lot of towns think briick is really cutesy-poo and have put it on some of their streets.

Even worse, imagine doing all your driving on dirt or gravel roads -- which then become mud roads whenever it rains.

About 30 years ago, some bunch of imbeciles persuaded road builders to cut grooves in the pavement, supposedly to prevent hydroplaning by allowing water to drain off faster. But the result was a hideously noisy & rough ride (probably tore up the tires, too), and the scheme was abandoned. No doubt there was a negative impact on FE as well.

In Hawaii, the roads are paved with crushed lava (after all, that's what the islands are made of). As a result, tires don't last nearly as long as they do on the mainland.

"Coyote" is right. The smoother the surface, the less rolling resistance and the higher the FE. However, if it's too smooth, both stopping distance and hydroplane risk increase to unsafe levels. I imagine engineers have to keep those conflicting interests in mind when building new roads or repaving old ones.

How funny... we've had both of those happen here. My local town thinks that brick garbage is pretty and puts it in crosswalks and stuff at interesctions. It's funny because if you take a turn fast enough through the interesction, the car will chirp the tires over the brick section. Do it in the rain and the car will whip sideways once you hit the pretty bricks. It's a serious safety problem.

It doesn's stop there, however. In one interesction, it was commercial on 3 corners, but housing right up to the intersection on the 4th corner. Well guess what; when cars transition from pavement to the brick and back to pavement it makes that "ba-thump, ba-thump" as the front and rear tires go over the bricks. They got so many complaints from homeowners that they made the city rip out all the brickwork from the intersection and pave the whole thing over with rubberized asphalt.

As for the grooved pavement, we had that on our US-60 freeway from back in the early 1980's. It is the loudest, worst condition, most likely to cause your car to meander, and has the most potholes of any freeway/highway in the valley. They've been slowly replacing it all with rubberized asphalt, but it's still amazing how terrible that stuff is. It's not like we really even get that much rain in Phoenix in the first place! Oh well. At least they seem to know what they're doing now.

I have that problem on the motorcycle when I make a turn in an intersection with thick painted white lines outlining the crosswalks. Talk about pucker factor!

<Best Tank Economy!><Best Tank Endurance!>



The new mileage database... well, it sucks! Not to mention the fact that my requests for help from the site owner have gone unanswered. So, I won't be tracking mileage on this site anymore. Many others have moved on as well, for similar reasons. There are several good sites out there to choose from. The two I picked are fueleconomy.gov and myhybridcar.com. But, check out the many alternatives for yourself, and see if another would suit your needs better.