What makes highway pavement so noisy??

[KarenLK]

On Interstates and major highways, some have such a roaring sound, while others appear "normal" - what is the difference??

 

[Clark]

Here's what I think.

It's the surface structure of the road interacting with the tread design.

As the car moves forward a new section of tire tread briefly hits the road, and the air in the tread is compressed by the weight of the car tire. Some of it escapes from the openings in the tread, some of it escapes via openings in the pavement surface, some of it stays partly compressed until the tread leaves that spot.

All these processes generated changes in air pressure (sound) that propagate away from the point of impact. Its different for every tread design and highway surface.

 

[KarenLK]

I will be needing new tires soon. Does anyone have a recommendation for "quiet" tires?? I currently have Michelins.

 

[wandering gnome]

You might want to check out tirerack.com. They have reviews and tire specs for tires.

 

[Passepartout]

Interesting question. It isn't the tires that are noisy, nor is it the highway that is noisy. It's the interaction between the two. Here's a study:
http://www.sciencedaily.com/releases/2003/04/030421083118.htm

Fwiw, DW has Michelin Hydro-Edge tires on her Prius. Wonderful wet/dry traction, but on a concrete highway, to my ears, they are seriously noisy! On asphalt, very quiet.

The study above did say that road noise is reduced on more porous surfaces.

Jim Ricks

 

[vacationhopeful]

Where I live the state transportation department has been "redoing" the interstate roads for the past 6 years. They expanded these sections in 1985-87 via adding a third lane of concrete and repairing the first 2 sections of the 1960's concrete roadway. In less than 5 years, most people noticed a distinct difference in the 3rd (high speed) lane which trucks had never been allow to run in (congestation in NJ). It was wavy, causing most regular drivers to perfer the oldest 2 lanes with the trucks.

So the state DOT decide 6 years ago to do more repairs. They ripped all the concrete roadways out, put in some type of drainage piping along the edges, bring in lots of new fill, and put down some type of composite blacktop. It seems to have reflective pieces in it, repels water more so and sounds different from older blacktop type surfaces. It has not yet "grooved" to the heavy traffic, but does "melt" when there is a vehicle fire on it.

Didn't do anything to the exit ramps which were built in the very early fifties or from the original "limited access" highway from the 1930s ... think of a current cloverleaf being twice as big as these exit/on ramps of this interestate. My bet is these ramps are from the 1930's, as the 1950s NJ Turnpike has bigger ramps. I figure the EPA requirements have kept these ramps as "preexisting", limiting any improvements.

Yes, I too believe there is a different surface material used today.

 

[nightnurse613]

We live in Arizona and they began a re-paving project by using a mixture that used old tires (a great environmental thing). Apparently they had to get the USDOT to allow this variation but, the project was so successful in lowering road noises (at least a couple of decibels?) that, soon afterward all locations near the highway wanted it. It looks good and quiets things a little and I think is cheaper but it does wear out a little quicker. Of course, about the time the neighbors got the roads quieter, the kids started putting loud performance mufflers on their cars which pretty much canceled out the noise benefit.

 

[Talent312]

On Interstates and major highways, some have such a roaring sound, while others appear "normal" - what is the difference??

Others more knowledgable than I will say its where the rubber hits the road and cite science as proof, but me, I'll say that the problem is your car. If you had a car with better sound insulation, they'd both be quiet. Car+Driver or Motor Trend, I forget which, measures cabin noise in their comparison tests.

 

[GadgetRick]

Others more knowledgable than I will say its where the rubber hits the payvement and cite science as proof, but me, I'll say that the problem is your car. If you had a car with better sound insulation, they'd both be quiet. Car+Driver or Motor Trend, I forget which, measures cabin noise in their comparison tests.

This is assuming riding with the windows closed. Many of us do not and some of us have a convertible. No amount of soundproofing in the car will keep the noise out at that point.