Does this blow or what?~?  Here in the Houston area were are about to lower the speed limit in many areas from 70 to 55? Apparently this will fix the dirty air.

Sure seems to suck.
Do they really expect Texas drivers to slow down...yeah right...

They must not have learned anything the last time around.  Oh well, as long as it's not federal....

Do you think they will actually ENFORCE the 55 limit, because "I CANT DRIVE, 55"!!!!!!!!!!!!!!!

Actually, the speed limit already is 55 or 60 in every high density urban area I can think of. But as Chuck Norris said above, good luck enforcing it. I drive through Seattle doing 70 in a 60 zone all the time and never even get a second look from cops.

Ive been all over this from the getgo. They are pulling this communist shit in Fort Worth on HWY 35.

After my first inquirey via email, they sent me a BS graph showing the trend of vechicle emmisions (NO) lowering with increased speed. It was so useless Im not going to waste my time attaching it.  If you inquire to the people listed in this post, I'm sure they will send you one. Sheeples like graphs.

Here is some communique Between me and the TX DOT:

From: Susan Williams [mailto:[email protected]]
Sent: Tuesday, July 10, 2001 4:58 PM
To: Jason Olson-JOLSON1
Subject: RE: Request for Information


Sir:

The Texas Department of Transportation is pleased to respond to your enquiry
dated July 9, 2001, regarding the Environmental Speed Limits effects in
Tarrant County and the scientific research that they were based upon.

Mr. Wayne Young, Environmental Affairs, Austin, has developed a Mobile5a
chart that was approved by EPA, as a mobile source rate model.  Young
modeled and developed the chart for 2007, using the following Harris County
data:
Houston temperatures for July
Houston VMT mix (% VMT by 8 vehicles types--this is from TPP via TTI)
Houston vehicle age distribution (% cars are 1, 2, 3...25 years of age-this
is from VTR)
TNRCC SIP control measures to be in place by 2007
    reformulated gasoline
    vehicle inspection/maintenance
    Federal clean fleet vehicle
    Federal heavy duty vehicle requirements
Mobile5a takes considerable input data and results vary considerably based
when Texas data are compared to national defaults. Absolute numbers change
but the trends of what happens with speed changes remain the same.

The Mobile5a chart has been attached for you to study.  We appreciate your
contact with the Texas Department of Transportation and if you should
require additional information please contact us at (817) 370-6709.

Susan Williams
Public Information Officer
Fort Worth District
[email protected]





Susan (TX DOT),
Thank you for the prompt response and information.

I have evaluated the information present here and have noted that Mr. Youngs
experiments only take into account single vehicle emissions at 5MPH
increments from 40MPH to 65MPH. Surely, emissions from the tailpipe of
single vehicles under steady-state conditions is not an accurate
representation of real-life trends.

I seek additional information on emission trends that take into
consideration the:
# of traffic lanes
types of vechicles
different traffic densities (time of day)
"laminar flow" condition of traffic (frequent braking and re-accelerating,
will increase emissions)

Also, air quality samples should be recorded (along with weather conditions)
from the ambient air near the HWY, not directly from the tailpipe.  "Fudge
factors" representing government control factors should be left out.

Do you have contacts for my inquiries and rebuttals?

thank you,
Jason Olson

here is more........

Mr. Olson,
Thank you for your observations and comments about the Mobile model.  I will try to respond to some of your comments and refer you to EPA for additional details.

The EPA  mobile source emission rate model, Mobile5, attempts to replicate emissions from 8 vehicle types for vehicles 1-25 years old.  Emissions are estimated for
light duty gas vehicles (cars),
light duty gas trucks 1(pickups and SUVs weighing less than 6,000 lbs,
light duty gas trucks 2 (pickups and SUVs weighing 6,000 to 8,500 lbs),
heavy gas trucks (weighing over 8,500 lbs),
diesel cars,
light diesel trucks (pickups and SUVs less than 8,500 lbs),
heavy diesel vehicles (over 8,500 lbs) and
motorcycles

The model requires age date on each vehicle type (% vehicles that are 1,2,3...25 years old).  Emissions are estimated for each model year for each vehicle type.  These emission rates are then internally multiplied by the % of daily vehicle miles traveled for each model year and summed to create a fleet average for each vehicle type.  The fleet averages for each vehicle type are then multiplied by the % of daily vehicle miles traveled for each vehicle type and summed to create a composite fleet average.  The composite figures used in my chart represent an average of 25 model years for 8 vehicle types (200 combinations) instead of emissions from a single vehicle.  As you are aware, the 200 combinations do not cover all possible combinations of vehicle makes,  and engine and transmission types.

EPA uses vehicle inspection/maintenance data to estimate emissions for each model year and for most of the vehicle types (diesels and motorcycles are tested far less frequently than gasoline vehicles and have a less robust data set).  Inspection/maintenance data is based on the Federal Test Procedure, a 240 second test with numerous accelerations, decelerations, and idle periods to produce emissions for an average speed of 19.6 miles per hour.  The test does not include "hard" accelerations and has no speeds over 57 mph.  Since there is no historical data for future year emissions, EPA uses a "best-guess" approach for emissions in future years.

In theory, the Federal Test Procedure is a replication of rush hour commuting.  I agree with your comment that accelerations and decelerations increase emissions and would suggest that emissions during non-peak travel periods are probably overestimated using the EPA model.    EPA mandates that the Mobile model be used.

TxDOT provides a considerable amount of speed, highway volume, and emission data to TNRCC for developing emission inventories.  Future year speeds are based on national highway volume/capacity ratios and use hourly vehicles per hour per lane to estimate hourly speeds and roadway emissions.  We also conduct traffic count studies to determine the % of different vehicle types for facility types such as freeways, ramps, arterial and collector roads.  Due the number of roadways involved, we are unable to provide detailed counts for each road and provide averages for facility types.  We feel that these are representative for a metropolitan area but realize that they may not be exact for any particular roadway.

If you wish additional information on Mobile 5, I suggest this website:  
[url]http://www.epa.gov/otaq/m5.htm[/url]

If you would like more details on TNRCC model efforts and monitor placement , I suggest you try:
pbreiten @tnrcc.state.tx.us

Thanks to the Clean Air Act and Houston's non-attainment of ozone level caps, we are being forced into this BS.  

Some of the non-published causes include the Harris County Toll Road system, the controlled access (signal light on entrance ramps)highways and peak load power plants.  Peak load power plants are the primary point source polluter while the others give rise to the base pollution.

I'm not joking here guys, every time I look at the historicals for ozone alert hours, I see the precursors for ozone (HC and NOX) max out from 4-6 AM.  The ozone peaks at 12:00 to 4:00 PM as expected.  

The peak load plants are generating loads of NOX in the early morning hours to power the normal morning wake-up demand.  Then the highways become packed and with the stop-start inefficiencies of most cars, its no surprise we have ozone in the afternoon.

Slowing down will have NO measurable effect.  Mark my words because the new limit will be in effect by May of 2002 and by July we will hit 3 days out of attainment.  Boy will we be pfuct then.

and more yet......


Mr. Young,

I would first like to think you for providing me with some information about the Mobile model.

My goal here is to get a idea of the experimental method and results. I am not trying to be a pain in anyone's side and fully appreciate you taking the time to answer my questions.

The model does not
"The test does not include "hard" accelerations and has no speeds over 57 mph.  
My main argument is that in more order to accurately design a model of localized vehicle emissions one must consider:

1) Develope a model of average vehicle emmission / speed. This seems to have been accomplished using the Mobile5 model as descibed below. I offer that better models could be produced outside the laboratory with mobile "sniffers" placed on vechicles actually driving through the test section under different speed limits (which would apply to ALL other vechicles in the experiment).

2) Develope models for these varibles:

A) Hwy efficiency per set speed limit (# of vechicles LEAVING a section of test HWY - the number of vechicles entering a test section of HWY per a given period of time)

B) avg. vechicle velocity per time (INSTANTANIOUS vechicle speed at any time (t) inside the section of test HWY)

C) avg. vechicle acceleration per time (INSTANTANIOUS vechicle acceleration (or braking) at any given time (t) inside the section of HWY)

D) Hwy efficiency per set speed limit (# of vechicles LEAVING a section of test HWY - the number of vechicles ENTERING a test section of HWY per a given period of time)

All of the variable stated will vary with the HWY volume, which will obviously vary with the time of day. To simplify the experiment, one could use a counter to monitor HWY Efficiency (A) per set speed limit for peak and off-peak periods.


Jason Olson


_______________________________________
no resonse......


-Boom

that would be on the smaller two lane suburban streets  right
cixi

75 remains the speed limit in AZ.

It appears to affect several counties.  I hope it's not going to be lowered for Intrastate traffic, that will never work.  All of you who don't live in Texas please realize our counties are often bigger than your state.  We drive a lot here and 55 is toooooo ssslllloooooowwwwwww........

cixi,

negative, Houston is on the EPAs shit list and Fort Worth is failing ozone requirements.
The government is threatening to withhold all state HWY funds if the two cities do not start to comply to the standards or atleast show some improvement.

The bird brains in local government are grabbing at straws to reduce emmisions.  Former Gov GWB told the EPA to get phucked a few years ago when the EPA tried stepping in.  GWB fought the lower emmision requirements for vechicles. The gov basically wanted about 25% of these cities civilian's vechicles off the road.

It is true that a lower speed (not lower spped in general, there is a "sweet spot") will produce lower emmisions.  However, I was trying to point out there are more variables involved.  One must look at the HWY and the population of vechicles. I believe there are two inverse trends that relate to vechile emmissions; the congestedness of the hwy and the ave speed of the vechicles.


-Boom

All of this EPA stuff is a bunch of bullshit. If you want to get down to it, then look for the dollar signs $$$. Since the speed limit has been raised, the number of speeding tickets written on Texas highways has dropped considerably. Just ask the DPS for the data on that and see what they say.

First they opposed the speed limit changes because the highways would become death traps. This mysteriously never happened as the death rate stayed the same. Now, it seems we are polluting too much.

Think I would get a ticket for driving an electric car 70mph in a 55mph zone? You bet your sweet ass I would.


Thank the Lord I have a [b]FREE[/b] attorney....

Speeding tickets are a tax on people who like to drive fast

Speaking of $$$
Somewhere I have statistics that show a a substantial coorelation between a cities economy and the relative movement (speed) of it's roadway infrastructure.

In short; 70MPH=better ecomomy

Better for both the government and the people.

High speed limits [i]and[/i] the right to carry. Is this state great or what?

Interesting.  New Jersey(known for its air quality) is about to raise the speed limits on some of the interstate type roads from 55 to 65.  About three years ago, the first few sections were raised from 55 to 65 amid crys of impending doom.  After three years, very little changed in the ways of death or even accident rates.  Of four major stretches of road, one went up, one unchanged & two went down.  All of the changes were statistically insignificant.

Pretty soon, I'll be legal driving at 65 almost all the way to work.

Have to get a faster car.  This old Sub' has a hard time at 70.

AR50troll,
having lived in Sugar Land and Missouri City what does it matter what the speed limit is ?
Ain't nobody paying attention anyway.
[:K]