MIT Study: Stiffer Roads = 3% better FE

[NeilBlanchard]

I posted this recently: http://ecomodder.com/forum/showthrea...ers-22015.html

I'd guess that the road bed can be improved in the way it supports bituminous paving? The major problem with concrete is that it is too stiff, and when the ground under it freezes, it heaves a LOT at the joints. Rapid heat expansion also stinks -- watch how the SUV *launches* into the air when it drives over buckled highway surface, starting at ~0:43 into this video:

http://www.youtube.com/watch?v=b0NrS...tailpage#t=37s

[euromodder]

That's old tech Neil.

Continuously laid concrete - i.e. without joints ! - has been around for over 25 years.
It stays remarkably smooth - well, at least in our moderate climate.

We have a stretch of road here, laid in the late 1980s, that'd still be baby-bottom smooth if it wasn't for the road authority's desire to cut holes in it !

The stretch that was laid a few years ago, is nowhere near this quality however


Old style concrete plates do shift - up and down - likely because they lack the sheer weight and the resistance to movement of a continuous slab.

[gone-ot]

...extend that whole "thought process" up even more and you understand why trains use steel rails...ie: ubber smoothness!

[rmay635703]

Originally Posted by euromodder

That's old tech Neil.

Continuously laid concrete - i.e. without joints ! - has been around for over 25 years.
It stays remarkably smooth - well, at least in our moderate climate.

We have a stretch of road here, laid in the late 1980s, that'd still be baby-bottom smooth if it wasn't for the road authority's desire to cut holes in it !

The stretch that was laid a few years ago, is nowhere near this quality however

To bad the concrete roads here in Wisconsin are replaced every year and are broken up wrecks in 6 months.

My best FE has always been on smooth newly laid asphalt, concrete launches my car around and feels like driving on a horse.

I think the best road would be the tire/asphalt hybred material that lasts 25+ years despite the extra give.

Concrete up north here turns to crap after the 1st winter.

[jamesqf]

Originally Posted by SentraSE-R

I might choose I-80 over US 50 for a weekend drive to Reno for a 3% gain in FE, but I'd need to know what each highway is paved with before starting the trip.

It also depends a lot on how much wear the road has had. I haven't driven it recently, but there was a time when the stretch of I-80 between Donner Summit and (roughly) Auburn was so badly worn that I was worried about high-centering the Insight on the ruts worn into the concrete. It was also quite rough, with the concrete worn well down into a layer of about 2" or larger aggregate...

Smoothness also matters a lot. I can see a noticeable increase in mpg on concrete just by moving out of the most worn parts.

[ksa8907]

Originally Posted by Old Tele man

...extend that whole "thought process" up even more and you understand why trains use steel rails...ie: ubber smoothness!

that and steel is really the only economical material that is hard enough, and still resilient to impact, that can hold almost 6,000psi in compression.

makes you wonder what the rail looks like in slow motion as a loaded car or engine rolls over it. wonder how much deflection you get.

ps. quick math of 140 ton rail car, 8 wheels, 3x1 contact patch(est)

[Frank Lee]

We should have steel roads! Hmmmm...

[gone-ot]

Originally Posted by Frank Lee

We should have steel roads! Hmmmm...

...could eliminate "flat" tires!

[F8L]

Originally Posted by jamesqf

It also depends a lot on how much wear the road has had. I haven't driven it recently, but there was a time when the stretch of I-80 between Donner Summit and (roughly) Auburn was so badly worn that I was worried about high-centering the Insight on the ruts worn into the concrete. It was also quite rough, with the concrete worn well down into a layer of about 2" or larger aggregate...

Smoothness also matters a lot. I can see a noticeable increase in mpg on concrete just by moving out of the most worn parts.

They fixed it.

They put in a bunch of concrete around the I-80 Madison Blvd to Auburn Blvd. area (approx). It's soooo smooth even compared to the new asphalt they just laid. I just wish I didn't have to drive on it during construction. The rock debris ruined the windshield and front end of my old Prius and now it is tearing up my brand new Prius. I swear the entire road from Woodland to Auburn (my commute) is being replaced! Ugg

[SoobieOut]

Maybe we need a new GPS setting to choose the routing with smoothest roads.

Could be a selling point for Garmin over Tom Tom.