Chip seal and fuel economy

[Blape]

Been reading a lot about how cyclists dislike chip seal because of the rolling resistance, noise, and wear and tear. California used it extensively on the Angeles Crest Highway project and it's getting a lot of flack.

Physics says that the same issues hold true for cars. Are the drawbacks worth it? Do you see decreased mileage on chip seal roads?


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[Scott5114]

I would imagine that the difference would be marginal. While the car would experience more resistance due to the chipseal than the bike would, it would be of little consequence to the car because the car experiences much greater wind resistance and is heavier. Those forces would affect the car much more strongly than road friction.

[Blape]

Isn't friction a function of the normal pressure, and the car is much heavier than the bike? From experience it seems significant. I think the reason the cyclists are up in arms about it is because they have to literally pedal thru it. In a car there's no physical exertion outside of squeezing a pedal.


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[triplemultiplex]

Chip seal sucks ass, in my opinion.  It makes the road way noisier, the sharper edges on the rock pieces increase tire wear and those pebbles invariably become 'unstuck' and start flying around chipping windshields and paint jobs.  I'm currently in New Mexico where they even chip seal the goddamn interstates and I got yet another stone chipped windshield on a company vehicle just yesterday for like the fourth time in as many months.

I can't understate the noise difference it causes. At highway speeds, it makes the vehicle sound like a damn jet airliner.  When a chip seal segment ends and you go back to plain, ol' asphalt, that's when you notice how terribly loud the road had been.  Not everyone is driving around in the automotive equivalent of noise-cancelling headphones.

Cyclists probably hate it because those loose pebbles accumulate along the edge of the travel lane where they are usually riding.  It's gotta be like riding on gravel for them especially if it's a recent addition to the pavement.

I consider chip seal a waste of time and money and a make-work program for construction companies and auto-glass repair shops.

[Scott5114]

Chipseal is fine on a rural county road where the alternative is that or gravel. It's a poor choice for a state highway, though, and putting it on an interstate is insane.

[US71]

Chipseal is fine on a rural county road where the alternative is that or gravel. It's a poor choice for a state highway, though, and putting it on an interstate is insane.

MoDOT "cheap seals" a lot of secondary highways. AHTD "cheap seals" a lot of lesser-driven state highways.

[J N Winkler]

Isn't friction a function of the normal pressure, and the car is much heavier than the bike? From experience it seems significant. I think the reason the cyclists are up in arms about it is because they have to literally pedal thru it. In a car there's no physical exertion outside of squeezing a pedal.

I don't think the cyclists object to chipsealing because it raises the rolling resistance.  I have cycled extensively on both chipseal and smooth asphalt and there isn't really any difference I have been able to feel in terms of pedal effort, which depends largely on the gradient and the direction the wind is blowing.

I suspect the cyclists may object to chipseal in the case of the Angeles Crest Highway if it is being used to postpone full-depth pavement reconstruction.  Chipseal is often used as a temporary fix for raveled patches, which are very uncomfortable to cycle on.  They can barely be felt in a car but on a bicycle, which is unsprung, they feel a little like washboarding on gravel does in a car.

[Indyroads]

Chipseal is fine on a rural county road where the alternative is that or gravel. It's a poor choice for a state highway, though, and putting it on an interstate is insane.

MoDOT "cheap seals" a lot of secondary highways. AHTD "cheap seals" a lot of lesser-driven state highways.

"cheap (sic) seal' is used on state highways in the west like California and Idaho since it is a cost effective way to prevent water penetration into the roadbed when the roadway surface begins to get micro-cracks. It does less wear and tear damage to tires then one might think. Most of the noise you hear is caused by air being compressed by the tires against the road surface.

[froggie]

Concur with Indyroads.  Chip seal is an effective way not just to prevent water intrusion but also to extend pavement life, especially on lower-volume roads that are way low on the totem pole for resurfacing.

[roadfro]

The "chips" in a chip seal are very small aggregates, less than about 1/4" in diameter...the damage to vehicles or increased wear on tires is pretty negligible.

In Nevada, chip seals are a highly-utilized part of the pavement preventative maintenance programs of NDOT & local agencies. They are often used on rural low-volume state highways and county roads to extend pavement life where reconstruction wouldn't be cost effective for the volume of traffic. Chip seals are also used quite extensively in urban areas on residential streets and minor arterials to extend pavement maintenance dollars to greater amount of streets, especially where more extensive reconstruction wouldn't be warranted. The street I grew up on was built in 1986, just received a chip seal a couple years ago (only the second major maintenance project in the life of the street)--the pebbles were mostly ground into the pavement or gone after a few weeks, and the cracks in the road were sealed up nicely.

[thenetwork]

In my little corner of Colorado, they like to chip seal roads which were newly paved less than 2-4 years prior.  The road surface was still in near-mint condition, but then they decide to "rough it up".  They do it on all highways -- residential, rural and interstate.