Cyclebum

You know. The rough aggregate with high rolling resistance that is pervasive on seal coated highways in Texas. It's the bane of cyclist and motorist alike. Noisy, tire chewing, gas guzzling stuff.

My question is: When traveling by bike or car in other states, do you recall encountering much of the type of rough seal coat used in Texas? I don't, raising the question of why is TDOT so enamored of the stuff? If it's so great, why don't we see it used extensively in all states? Are they just not as savvy as TDOT?

I am trying to gather as much info as possible before firing off a letter to Austin officialdom. My research so far does not seem to support their argument that it is 'safer.' The argument that it is 'cheap' doesn't jive with fact that it is rarely used on city streets.

hyegeek

Idaho uses it quite a bit. It is used because of cost. The drivers get to cover a large portion of the resurfacing costs as they smooth the roads down instead of getting the machines out there to put a traditional surface on.

Creakyknees

I suggest you check in with Bike Texas and the other advocacy orgs, they've been working on this topic for quite a while.

keithm0

It's commonly used here in Washington State, at least on the west side of the Cascades. It seems to be more prevalent in farming areas -- Skagit County has some of the worst chip seal I've ever biked on.

FWIW, I rode my first Hotter'n Hell Hundred this year. I had been warned about the endless miles of chip seal on this ride, but it wasn't nearly as bad as I expected.

DTSCDS

Wondering if our particular variety is somehow related to summer temperatures. The surface temperature of the road in the hottest part of the hottest days would surely require some type of specialized tar/asphalt.

I don't know if things have changed in recent years, but a decade or more ago I remember reading an article that said our road financing system was completely jacked up. Federal law required that the lowest bid be the winner--even if their were a more technologically advanced, longer lasting, better solution that costs more. The article also said that the regulations required that the company that submits the winning (lowest) bid also be the company with first shot at any repair work that needs to be done.

Anybody else see where this plan will lead? Submit a lowball bid based on the crappiest materials you can get by with, knowing that you will get to come back to fix the inevitable issues down the road. (No pun intended)

Smoother, longer-lasting roads are out there, but unless our system is revamped I don't see us getting them anytime soon.

Ground Hog

Here in Connecticut they use it on secondary roads instead of the old oiling method or repaving. Major routes and highways get repaved. Now that I think about it, roads that the state takes care of don't use chip seal but town roads do. Every town decides what, when and how roads will be repaired.

Don in Austin

I don't have any problem with it at all running 28s.

Don in Austin

Jamesw2

https://www.bikesdirect.com/products/...us_al_xiii.htm

Note the specs on this bike as an example . . they have put a wider fork on the front for tire clearance and wa la you have a bike made for chip seal and rough city streets

As for me i went to 28's on the same bike (Corvus) but a different model year and different fork

On long rides of over 60 miles i use the touring bike with 35mm tires

Cyclebum

Have to wonder if you're talking about the same seal coat surface that I'm complaining about. I guess you are, as I've ridden the Hill Country where the rough aggregate is everywhere. Wider the tire, smoother and slower the ride. I run 38s on the TE and hate the stuff.

Werkin

I run 42s (47 actual) @38psi, and this road topping still beats me up through hands & feet. A Thudbuster isolates my bottom from the aggravation.

nkfrench 

The really big boulder chipseal is miserable to ride on. It sucks most of the fun and a lot of the speed out of riding. I've abandoned several favorite routes after the roads were repaved with the stuff.
I've talked to TXDOT and it's all about money. I pled with local TXDOT people that the road buzz has caused nerve damage in my hands. I've had to be off the bike for 2 weeks due to cyclist palsy.
Could they at least leave the road shoulders alone? The main roadway gets smoothed down by motorized traffic, but the shoulders just stay rough and fill with debris.
As above, there are some good educational materials and good efforts going with Texas bike advocacy groups.
My bike won't take a tire 28mm or wider. Nor do I want to give up my wonderful road bike.
After taking some long downhills in Parker County, I've had to stop and dismount until I got the feeling back in hands and feet -- and inspect the bike to make sure all the components were still firmly attached.
Night rides are the worst, the road buzz beats up the headlights and batteries.

Don in Austin

Maybe I have been lucky, but I went on a group ride where there was fresh chip seal and everybody complaining to where they changed the route the following week, and I just didn't see that much of a problem. One thing that does happen is that since my 28s fit with only 5mm or so of clearance, when it is fresh and sticky a chip will get caught between the tire and the front caliper and make a scratching noise. All I have to do is roll the bike backwards a couple of feet to dislodge it, but my fellow riders get freaked out. Maybe there is chip seal worse than I have encountered. I have ridden on it in Austin, outside of town, Fort Davis area, (well seasoned and packed) and they recently laid it down on my own street. Chip seal is way down the list of my complaints about cycling infrastructure. If it was ever a big problem I would just ride on the appropriate bike and tires.

Don in Austin

Cyclebum

I am now a member of Bike Texas, an advocacy organization based in Austin. Getting rid of rough aggregate chip seal in Texas is a minor part of their agenda, safety for cyclists being the main goal. They have made TDOT aware of cyclist's objections. My focus will be from a motorist standpoint and the noise level. Tire wear and reduced gas mileage are real, but minor.

I was told that after TDOT paved a popular cycling route with rough aggregate, there was such an uproar that they overlaid it with a smooth surface. There is hope, at least in the Austin area.

When I see objective proof that rough aggregate is safer and cheaper than pebble aggregate, I'll shut up. What little I've been able to discover so far is that there is no proof. Bike Texas also says TDOT has no proof, at least about the safety advantage. The fatality rate for Texas is 1.3 vs 1.1 nationally.

Seems that if the rough aggregate is so much safer and cheaper than pebble, every town in Texas would be using it. They don't.

michaelcycle

Chip seal, aka seal coat is not often used on city streets because it will not hold up to slow moving, tight turning traffic such as at intersections or driveways. Tire friction will shear the rock off the asphalt and you will be left with a pile of gravel and a shiny black spot. It is only appropriate on straight sections. However, I expect to see more of it on city streets with improved asphalt binders and tighter agency budgets.

Chip seal vs. hot mix overlay is not really a valid comparison. They serve a different purpose and the cost of construction is dramatically different. Seal coat is a preventive maintenance measure and overlay is more of a rehab.

The reason chip seal is considered a safety improvement is due primarily to wet weather skid resistance. Crushed rock is used rather than smooth gravel for this and other reasons.

Large aggregate is more durable, and it allows more asphalt to be applied to the roadway surface which improves the length of time before the next required maintenance.

There are mountains of research and evidence proving the economy and safety of using seal coat as a preventive maintenance. You just won’t win any argument against it. If you knew all the facts and were in control of a budget yourself, you would probably recommend an aggressive seal coat program to preserve our state's roads. That’s why TxDOT does it.

If I were going to try to improve the situation for cyclist, I would NOT try to argue for the elimination of seal coat, because it won't happen. What I would do is ask your highway engineers (they work for you, the tax payer) to consider using a smaller aggregate for the shoulders. I think it would make sense for cyclist and engineers. For the main driving lanes I would use high rate of asphalt and a large, durable aggregate. For the shoulders, I would use a lower rate of asphalt and a smaller aggregate. In TxDOT lingo that would be grade 4 (roughly 3/8" rock) for main lanes and grade 5 (roughly 1/4" or smaller) for shoulders. Smaller rock and less asphalt = lower cost. More complicated construction and materials = higher costs. The two together could average out?

There is a safety argument for this as well. I often see cyclist riding the smooth wheel path to avoid the rougher but safer shoulders. It would obviously be better for everyone to get the cyclist onto the shoulder. (I’m talking highways, not city streets)

I used to ride a loop that included bits of state highway with terribly rough seal coat, and other sections of county roads that had chip seal with smaller aggregate. The county road section was chip seal, but was very smooth and comfortable. Seal coat isn't the problem, it's the size of the rock.
Hope that helps.

Cyclebum

michaelcycle, your remarks, well informed, logical, and nuanced, are well received. Thanks. More here than I've learned from a couple of visits with TDOT engineers. Are you one by chance?

I especially like your argument for fine aggregate use on shoulders. A 3 mile stretch of state highway near where I live, with a smooth shoulder paralleling course chip seal, was recently resealed. They covered all with the course aggregate. Guess it was easier than not, tho the shoulder was in good condition.

A lot of what TDOT does is a mystery to a layman. This includes why they chose 3 or 4 different types of material for a short stretch of highway. US 59, a major highway from Houston north, is variously paved with concrete, asphalt, fine and course aggregate, sometimes different material in adjacent lanes.

Do you by chance have any reference links to objective data showing course aggregate surfacing to be safer than fine, or concrete, or asphalt? Sure, the gripping characteristics are
probably better, but does this really translate into an actual reduction in the accident rate?

As I become better educated on this relative to TDOT, I want to reexamine my impression that the use of course aggregate is pretty limited in other states.

Thanks.

michaelcycle

Chip seal will often be applied to the full width of theroadway to ensure that the entire surface is waterproofed. It is a case by casedecision. The shoulder may not show visible wear or cracking, but an oldoxidized asphalt will allow water to penetrate. It is essential to preventwater penetration into the subgrade to prolong life. Pavement deteriorationoften starts at the edge and works its way in. I'm sure you've driven roadswith a steep drop off at the edge of pavement. Sealing shoulders is a long termstrategy to prevent these dangerous edge conditions.

All a chip seal does is waterproof, that's the goal. Thereis little or no structural improvement. To improve the structure, a hot mixpavement would have to be constructed. So, imagine a road with an overall widthof 32' (12' lanes, 4' shoulders) with an oxidized surface, minor crackingthroughout, and some minor rutting and cracking in the wheel path. A commonsolution is to chip seal the entire roadbed (32') to provide waterproofing andthen overlay the driving lanes (24') to address rutting/cracking. Pretty goodsolution, and you'll see it all over the state. Driving lanes end up smoothbecause they needed structural enhancement. Shoulders end up with chip sealbecause they don't need more pavement structure, they need waterproofing.

That’s the basic thought process.

This is a very old report, but may be what you are lookingfor:
https://library.ctr.utexas.edu/digitized/TexasArchive/thdresearch/133-3F_TxDOT.pdf


Search for transportation research here:
(keyword search for “surface texture safety” or similar)
https://library.ctr.utexas.edu/dbtw-wpd/textbase/websearchcat.htm
https://tti.tamu.edu/research/
https://www.trb.org/Main/Home.aspx

michaelcycle

Chip seal will often be applied to the full width of theroadway to ensure that the entire surface is waterproofed. It is a case by casedecision. The shoulder may not show visible wear or cracking, but an oldoxidized asphalt will allow water to penetrate. It is essential to preventwater penetration into the subgrade to prolong life. Pavement deteriorationoften starts at the edge and works its way in. I'm sure you've driven roadswith a steep drop off at the edge of pavement. Sealing shoulders is a long termstrategy to prevent these dangerous edge conditions.

All a chip seal does is waterproof, that's the goal. Thereis little or no structural improvement. To improve the structure, a hot mixpavement would have to be constructed. So, imagine a road with an overall widthof 32' (12' lanes, 4' shoulders) with an oxidized surface, minor crackingthroughout, and some minor rutting and cracking in the wheel path. A commonsolution is to chip seal the entire roadbed (32') to provide waterproofing andthen overlay the driving lanes (24') to address rutting/cracking. Pretty goodsolution, and you'll see it all over the state. Driving lanes end up smoothbecause they needed structural enhancement. Shoulders end up with chip sealbecause they don't need more pavement structure, they need waterproofing.

That’s the basic thought process.

This is a very old report, but may be what you are lookingfor:
https://library.ctr.utexas.edu/digitized/TexasArchive/thdresearch/133-3F_TxDOT.pdf


Search for transportation research here:
(keyword search for “surface texture safety” or similar)
https://library.ctr.utexas.edu/dbtw-wpd/textbase/websearchcat.htm
https://tti.tamu.edu/research/
https://www.trb.org/Main/Home.aspx

ausfix

You probably know the answer. Worrying about the comfort of cyclists is low on the priority list of our wonderful part-time legislators.

mtbikerinpa

They use chipseal processes a lot in PA also and I have lost a couple flats to the smaller grade since it is sharp. I even had one car wreck in my car due to sliding off a turn in light rain(aka "marbles effect"). The only saving grace is that we get some heavy rain storms every couple weeks(boo), so the loose gets rinsed pretty well. Needless to say they do it enough that it makes non-shielded tires other than knobby mtb tires a risk. Even with urban shielded tires I do end up sometimes at destination with a few mini stones embedded in the outer layer.

Around here I attributed it to the extensive use of Amish horses and iron wheel Amish equipment(both of which make a very recessed right wheel track).

Cyclebum

OK. It seems to be well established that course aggregate seal coat is the safest driving surface when skid resistance is factored. This is logical and proven with at least one in depth study referenced above. Far be it for me to argue for unsafe Texas highways, no matter how irritating they are to ride and drive on. Thanks again michaelcycle for your help.

Still wondering why I've never had a significant problem with course aggregate seal coat in any other state I've ridden or driven in. Either my memory is worse than I think it is, or most other states' highways are just not as safe as Texas highways and need more frequent maintenance. They best get with the program.

RoyIII

I just put 28s on a bike and they do smooth it out

Don in Austin

My experience.

You can demand that the road conform to your bike -- good luck with that! Far easier to make the bike conform to the road.

Don in Austin

Cyclebum

Yeah, a Surly Troll with 2" tires would conform.

Why Texas driver don't protest this noisy stuff more is a mystery.

Monoborracho

I have son who is an engineer with TxDOT. The cost difference between seal coat "chip seal" and smooth hot top asphalt would drop your jaw to the ground. You will see more and more of it everywhere.

Think bigger tires with lower pressure.

Condorita

Urban applications around here (Southern California) tend toward slurry seal to extend the life of the roadway between pavings. I have, however, even seen Cal-Trans chip seal, but the only time was down on I-8 between El Centro and Yuma. Chip seals, with a topping fog seal, are quite common in the agricultural areas, particularly in the Central Valley, but on the secondary roads. "Crack seal" is popular at all levels of highway/road maintenance. (I was drawn into this discussion by the subject header; I'm a professional in the petroleum-products transportation industry.)