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New speed limit soon?

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uncle sam
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Re: New speed limit soon?

Postby uncle sam » April 20th, 2017, 7:17 pm

I thought the purpose for speed limits were for better handling/ control and stopping.. never heard of road engineering .. hmm ok

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Re: New speed limit soon?

Postby kamakazi » April 20th, 2017, 7:23 pm

Engineered for a particular speed is referring to the design speed of the road.
The design speed dictates the geometric features of the road e.g superelevation, horizontal and vertical curves, visibility.
In easier terms
Superelevation - the banking on the turn
Vertical curves - the transition through hills and valleys
Horizontal curves - the transition through left and right turns


It also takes into consideration comfort of driver and passengers.

This is the reason why roads with higher speed limits are straighter and flatter than roads with lower speed limits.


Now actual speed limits can be set differently from design speed... that takes into consideration even more factors; but it is the place where the engineering starts and definitely isn't rubbish

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Re: New speed limit soon?

Postby Slartibartfast » April 21st, 2017, 9:30 am

Nissan12 wrote:
Slartibartfast wrote:
sMASH wrote:i thought the roads aren't engineered to be safe above 80kmph?

could really remember a lot of words read about the engineering.
Please tell me, exactly how do you "engineer" a road for a certain speed limit? Once you can answer that you will see why anybody that mentions that as a point against a higher speed limit is speaking utter rubbish. If you want to talk about safe highway speeds given the current wearing surface due to weathering, wear and tear and faulty construction then that is a different point and would only be applicable to specific locations of the highway inspected for such. Otherwise, please stop the spread of misinformation. It makes it worse for us


All physics (but hopefully some civil engineers here will chime in) horizontal curves and cross fall to counter centripetal and centrifugal forces, vertical curves for visibility and stopping distance based on speed.... Yeah, not just making a foundation and paving it...
Exactly. Design speed of a highway has mostly to do with its geometry as outlined in AASHTO Policy on Geometric Design of Highways. If you get your hands on it and you are able to understand the geometric requirements you would see that the majority of our highways are either already designed for speeds above 80km/hr or can easily be upgraded to that it is. Some locations may need to have reduced speed limits of 80km/hr (I'm thinking like the bend by Gasparillo flyover)

Here is some info to further the discussions. Below are design criteria for freeways taken directly out of AASHTO - A POLICY on GEOMETRIC DESIGN of HIGHWAYS and STREETS 2001. I used the worst case scenarios where I could and kept it as simple as possible for ease of reference.

Consider the sight distance design criteria. You need to be able to see far ahead enough to notice dangers and stop in time. The values below take into account reaction time and stopping distance to give a total required sight distance.

According to AASHTO - A POLICY on GEOMETRIC DESIGN of HIGHWAYS and STREETS 2001 - Exhibit 3-1 and 3-2.
Sight distance for a car at 80km/hr is 130m
Sight distance for a car at 10km/hr is 185m
Sight distance for a truck at 90km/hr on a 9% downgrade is 187m
(Makes sense for Heavy-T trucks to have a slightly lower speed limit)

For horizontal alignment taking into consideration the G forces on the car
According to AASHTO - A POLICY on GEOMETRIC DESIGN of HIGHWAYS and STREETS 2001 - Exhibit 3-14
Rounded Turning Radius for Vehicle traveling at 80km/hr with 4% superelevation (cross slope) = 280m
Rounded Turning Radius for Vehicle traveling at 100km/hr with 4% superelevation (cross slope) = 490m


I'll stop there for now but note that there is a lot more to the picture. Like how vertical curves affect sight distance. How grade and grade length affect truck speed and how truck speed affects traffic as well as how grade length affects truck braking.

All I want is for people to stop making uninformed statements like "Our highways nuh design for dat" to dismiss valid arguments. I'll leave you all with this

AASHTO - A POLICY on GEOMETRIC DESIGN of HIGHWAYS and STREETS 2001 wrote:SPEED

The speed of vehicles on a road or highway depends,
in addition to capabilities of the drivers and their vehicles, upon four general conditions: the
physical characteristics of the highway and the amount of roadside interference, the weather, the
presence of other vehicles, and the speed limitations (established either by law or by traffic
control devices)....

Design Speed
Design speed is a selected speed used to determine the various geometric design features of
the roadway. The assumed design speed should be a logical one with respect to the topography,
anticipated operating speed, the adjacent land use, and the functional classification of highway....

The selected design speed should be consistent with the speeds that drivers are likely to
expect on a given highway facility. Where a reason for limiting speed is obvious, drivers are more
apt to accept lower speed operation than where there is no apparent reason. A highway of higher
functional classification may justify a higher design speed than a lesser classified facility in
similar topography, particularly where the savings in vehicle operation and other operating costs
are sufficient to offset the increased costs of right-of-way and construction. A low design speed,
however, should not be selected where the topography is such that drivers are likely to travel at
high speeds. Drivers do not adjust their speeds to the importance of the highway, but to their
perception of the physical limitations of the highway and its traffic.
...

Where the physical features of the highway are the principal speed controls and where most
drivers choose to operate near the speed limit, a design speed of 120 km/h [75 mph] would serve
a very high percentage of drivers....

...On many freeways, particularly in suburban and rural areas, a design speed of 100 km/h
[60 mph] or higher can be provided with little additional cost above that required for a design speed of 80 km/h [50 mph]....

...Isolated features designed for higher speeds would not necessarily encourage drivers to
speed up, although a succession of such features might. In such cases, the entire section of
highway should be designed for a higher speed.
A substantial length of tangent between sections
of curved alignment is also likely to encourage high-speed operation. In such situations, a higher
design speed should be selected for all geometric features, particularly sight distance on crest
vertical curves and across the inside of horizontal curves....

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Re: New speed limit soon?

Postby Slartibartfast » April 21st, 2017, 9:39 am

kamakazi wrote:Now actual speed limits can be set differently from design speed... that takes into consideration even more factors; but it is the place where the engineering starts and definitely isn't rubbish
People that want to keep the 80km/hr speed limit need to ask themselves what the purpose of a speed limit is. Answer is road safety. They need to then ask, how do they know how fast can one drive while still being safe. Answer is, engineering design or evaluation. Sadly, most don't make it to the second part. People that want the speed limit raised are just asking for an honest and fair evaluation. Having a road designed for 120km/hr and a speed limit of only 80km/hr and strictly enforcing the speed limit seems like a quick and easy way to basically tax the population further for no reason. I say no reason because someone driving at 90km/hr on a road designed for 120km/hr is still driving safely and yet being punished as though they are not.

Somebody please tell me if I not making sense.

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Re: New speed limit soon?

Postby crazybalhead » April 21st, 2017, 9:41 am

Slartibartfast wrote:
Nissan12 wrote:
Slartibartfast wrote:
sMASH wrote:i thought the roads aren't engineered to be safe above 80kmph?

could really remember a lot of words read about the engineering.
Please tell me, exactly how do you "engineer" a road for a certain speed limit? Once you can answer that you will see why anybody that mentions that as a point against a higher speed limit is speaking utter rubbish. If you want to talk about safe highway speeds given the current wearing surface due to weathering, wear and tear and faulty construction then that is a different point and would only be applicable to specific locations of the highway inspected for such. Otherwise, please stop the spread of misinformation. It makes it worse for us


All physics (but hopefully some civil engineers here will chime in) horizontal curves and cross fall to counter centripetal and centrifugal forces, vertical curves for visibility and stopping distance based on speed.... Yeah, not just making a foundation and paving it...
Exactly. Design speed of a highway has mostly to do with its geometry as outlined in AASHTO Policy on Geometric Design of Highways. If you get your hands on it and you are able to understand the geometric requirements you would see that the majority of our highways are either already designed for speeds above 80km/hr or can easily be upgraded to that it is. Some locations may need to have reduced speed limits of 80km/hr (I'm thinking like the bend by Gasparillo flyover)

Here is some info to further the discussions. Below are design criteria for freeways taken directly out of AASHTO - A POLICY on GEOMETRIC DESIGN of HIGHWAYS and STREETS 2001. I used the worst case scenarios where I could and kept it as simple as possible for ease of reference.

Consider the sight distance design criteria. You need to be able to see far ahead enough to notice dangers and stop in time. The values below take into account reaction time and stopping distance to give a total required sight distance.

According to AASHTO - A POLICY on GEOMETRIC DESIGN of HIGHWAYS and STREETS 2001 - Exhibit 3-1 and 3-2.
Sight distance for a car at 80km/hr is 130m
Sight distance for a car at 10km/hr is 185m
Sight distance for a truck at 90km/hr on a 9% downgrade is 187m
(Makes sense for Heavy-T trucks to have a slightly lower speed limit)

For horizontal alignment taking into consideration the G forces on the car
According to AASHTO - A POLICY on GEOMETRIC DESIGN of HIGHWAYS and STREETS 2001 - Exhibit 3-14
Rounded Turning Radius for Vehicle traveling at 80km/hr with 4% superelevation (cross slope) = 280m
Rounded Turning Radius for Vehicle traveling at 100km/hr with 4% superelevation (cross slope) = 490m


I'll stop there for now but note that there is a lot more to the picture. Like how vertical curves affect sight distance. How grade and grade length affect truck speed and how truck speed affects traffic as well as how grade length affects truck braking.

All I want is for people to stop making uninformed statements like "Our highways nuh design for dat" to dismiss valid arguments. I'll leave you all with this

AASHTO - A POLICY on GEOMETRIC DESIGN of HIGHWAYS and STREETS 2001 wrote:SPEED

The speed of vehicles on a road or highway depends,
in addition to capabilities of the drivers and their vehicles, upon four general conditions: the
physical characteristics of the highway and the amount of roadside interference, the weather, the
presence of other vehicles, and the speed limitations (established either by law or by traffic
control devices)....

Design Speed
Design speed is a selected speed used to determine the various geometric design features of
the roadway. The assumed design speed should be a logical one with respect to the topography,
anticipated operating speed, the adjacent land use, and the functional classification of highway....

The selected design speed should be consistent with the speeds that drivers are likely to
expect on a given highway facility. Where a reason for limiting speed is obvious, drivers are more
apt to accept lower speed operation than where there is no apparent reason. A highway of higher
functional classification may justify a higher design speed than a lesser classified facility in
similar topography, particularly where the savings in vehicle operation and other operating costs
are sufficient to offset the increased costs of right-of-way and construction. A low design speed,
however, should not be selected where the topography is such that drivers are likely to travel at
high speeds. Drivers do not adjust their speeds to the importance of the highway, but to their
perception of the physical limitations of the highway and its traffic.
...

Where the physical features of the highway are the principal speed controls and where most
drivers choose to operate near the speed limit, a design speed of 120 km/h [75 mph] would serve
a very high percentage of drivers....

...On many freeways, particularly in suburban and rural areas, a design speed of 100 km/h
[60 mph] or higher can be provided with little additional cost above that required for a design speed of 80 km/h [50 mph]....

...Isolated features designed for higher speeds would not necessarily encourage drivers to
speed up, although a succession of such features might. In such cases, the entire section of
highway should be designed for a higher speed.
A substantial length of tangent between sections
of curved alignment is also likely to encourage high-speed operation. In such situations, a higher
design speed should be selected for all geometric features, particularly sight distance on crest
vertical curves and across the inside of horizontal curves....



DANNN!!!! You not supposed to be concentrating on the fiddly bits around fjords?

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Re: New speed limit soon?

Postby kamakazi » April 21st, 2017, 9:51 am

Aren't you forgetting in engineering there is something called "factor of safety"

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Re: New speed limit soon?

Postby JF.K » April 21st, 2017, 10:17 am

I think the point sMASH was initially making is that the government and people in "power" were making statements that the "Engineering of the Roads" was the reasoning behind they not raising the 80km/hr speed limit.

Now all of a sudden they considering to raise it. It appears as though they were just BS people all the time (obviously).
And most likely the Syrians and their children getting pull over too much so a shot was called.

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Re: New speed limit soon?

Postby Slartibartfast » April 21st, 2017, 4:50 pm

crazybalhead wrote:DANNN!!!! You not supposed to be concentrating on the fiddly bits around fjords?
That's was perfected in Earth Mark 2

kamakazi wrote:Aren't you forgetting in engineering there is something called "factor of safety"
Nope. My point is that there's a whole lot of gum bumping with no information to back it up. I just want to hear what info they based this 80 km/hr speed limit on. Like JF.K said

JF.K wrote:I think the point sMASH was initially making is that the government and people in "power" were making statements that the "Engineering of the Roads" was the reasoning behind they not raising the 80km/hr speed limit.

Now all of a sudden they considering to raise it. It appears as though they were just BS people all the time (obviously).
And most likely the Syrians and their children getting pull over too much so a shot was called.
They quoting "Engineering of the Roads" as a reason with absolutely no information. I want to see the reasoning behind their statements.

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Re: New speed limit soon?

Postby De Dragon » April 21st, 2017, 5:31 pm

Slartibartfast wrote:
crazybalhead wrote:DANNN!!!! You not supposed to be concentrating on the fiddly bits around fjords?
That's was perfected in Earth Mark 2

kamakazi wrote:Aren't you forgetting in engineering there is something called "factor of safety"
Nope. My point is that there's a whole lot of gum bumping with no information to back it up. I just want to hear what info they based this 80 km/hr speed limit on. Like JF.K said

JF.K wrote:I think the point sMASH was initially making is that the government and people in "power" were making statements that the "Engineering of the Roads" was the reasoning behind they not raising the 80km/hr speed limit.

Now all of a sudden they considering to raise it. It appears as though they were just BS people all the time (obviously).
And most likely the Syrians and their children getting pull over too much so a shot was called.
They quoting "Engineering of the Roads" as a reason with absolutely no information. I want to see the reasoning behind their statements.

You sir, are setting yourself up for a lot of disappointment :lol: The Gov't threw out a set of useless quotes and hoped that "engineering" in the BS answer would calm down their base. They didn't ,a nd usually do not, count on someone actually knowing that they are talking cacaholery and calling them out on it.

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Re: New speed limit soon?

Postby Morpheus » April 21st, 2017, 8:23 pm

They could design till they drop down. Once these natives doh obey other road laws besides just the speed limit, it will still be chaos IMHO...

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Re: New speed limit soon?

Postby sMASH » April 21st, 2017, 8:42 pm

De Dragon wrote:
Slartibartfast wrote:
crazybalhead wrote:DANNN!!!! You not supposed to be concentrating on the fiddly bits around fjords?
That's was perfected in Earth Mark 2

kamakazi wrote:Aren't you forgetting in engineering there is something called "factor of safety"
Nope. My point is that there's a whole lot of gum bumping with no information to back it up. I just want to hear what info they based this 80 km/hr speed limit on. Like JF.K said

JF.K wrote:I think the point sMASH was initially making is that the government and people in "power" were making statements that the "Engineering of the Roads" was the reasoning behind they not raising the 80km/hr speed limit.

Now all of a sudden they considering to raise it. It appears as though they were just BS people all the time (obviously).
And most likely the Syrians and their children getting pull over too much so a shot was called.
They quoting "Engineering of the Roads" as a reason with absolutely no information. I want to see the reasoning behind their statements.

You sir, are setting yourself up for a lot of disappointment :lol: The Gov't threw out a set of useless quotes and hoped that "engineering" in the BS answer would calm down their base. They didn't ,a nd usually do not, count on someone actually knowing that they are talking cacaholery and calling them out on it.



is like a turbine with a mechanical trip speed of 5200 rpm, and every body forced to abide by it. then one day in a meeting, it was decided that 6100 rpm is the actual mechanical trip.....

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Re: New speed limit soon?

Postby nick639v2 » April 24th, 2017, 3:55 pm


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Re: New speed limit soon?

Postby uncle sam » April 24th, 2017, 4:22 pm

level fyaz given... In her defense it prob felt like 80 in the benz lol

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Re: New speed limit soon?

Postby amd-dude » April 24th, 2017, 6:44 pm

Can't blame her, in my 320, 220km feels normal and planted.

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Re: New speed limit soon?

Postby viedcht » April 24th, 2017, 6:57 pm

^On Trinidad highways?

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Re: New speed limit soon?

Postby Strugglerzinc » April 24th, 2017, 7:10 pm

Not like she gonna get charged more for going faster. Make the best of it.

If i get caught, may as well make it 160+.

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Re: New speed limit soon?

Postby greggle71 » April 24th, 2017, 7:42 pm

Lucky she didn't get charge for dangerous driving

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Re: New speed limit soon?

Postby Strugglerzinc » April 24th, 2017, 9:09 pm

At least the police know the difference between speeding and dangerous driving. You must be one of those who drive 80 on the right lane.

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Re: New speed limit soon?

Postby kamakazi » April 25th, 2017, 10:42 am

Thank you woman... Cause if is the same $1000 charge for going 90 vs 190kph.... If you breaking the law... Might as well go all out.

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Re: New speed limit soon?

Postby Slartibartfast » April 25th, 2017, 1:18 pm

Well when you trying to negotiate a new speed limit you have to start high. So she basically showing that our roads could handle 210 km/hr. Now it's up to them to show why we need to keep it at 80. :lol:

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Re: New speed limit soon?

Postby amd-dude » April 25th, 2017, 2:09 pm

Or we could implement different speed limits for different cars, tiida and ad wagon is 80km, better jap cars like lexus and toyota could go 100-120 and the germans can do 200+ and no truck/backhoe/bus on the highway, gih dem a next lane.

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Re: New speed limit soon?

Postby bluesclues » April 25th, 2017, 8:39 pm

Wah you mean better jap cars? U tryin to say a lexus better than a tiida? Boy rock so eh..

LOL

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Re: New speed limit soon?

Postby Monkey Man » April 28th, 2017, 6:56 am

bluesclues wrote:Wah you mean better jap cars? U tryin to say a lexus better than a tiida? Boy rock so eh..

LOL


ent dai d fry chikken place?

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Re: New speed limit soon?

Postby christopherwilliams2 » April 29th, 2017, 7:30 am

so....any update on this?
or money still haffi mek on the speed traps?

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Re: New speed limit soon?

Postby drchaos » April 30th, 2017, 9:18 am

Nah meh boy Rohan say it will take some time! Changing laws takes more time than enforcing ones that already exist.

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Re: New speed limit soon?

Postby christopherwilliams2 » May 7th, 2017, 2:24 pm

drchaos wrote:Nah meh boy Rohan say it will take some time! Changing laws takes more time than enforcing ones that already exist.


alright cool :|

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Re: New speed limit soon?

Postby Allergic2BunnyEars » May 7th, 2017, 2:32 pm

Speed trap is a revenue maker. They not gonna change speed limits I feel. Same way they throw out talk of taxing turbo cars. Yes sometimes government engages in ole talk and y'all eat it up and beat up with every line. Sad.

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Re: New speed limit soon?

Postby AutoSport » May 7th, 2017, 5:15 pm

FALSE NEWS.
THIS WAS DENIED BY THE AUTHORITIES.

But seriously, how much different is what used to be with stopwatches and a police with a newspaper and another risking his life to stop the speedster.

To a whole big SUV on top a flyover, a 100 drivers flashing lights in the oncoming opposite side of the highway, plenty police vehicles down the road from the camera man, everybody slowing down, and still have a police man in the centre of the road with a '"walkie talkie" looking for the speedster.

Really!

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Re: New speed limit soon?

Postby j.o.e » May 7th, 2017, 7:14 pm

Nah dem fellas getting better. New method is two cars working in tandem. One with the speed gun, one patrolling up ahead that pulls you over. Happened to me on Easter weekend. So rather than one big road block they pull over individual cars. No chance for the other side to notice and flash lights.

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Re: New speed limit soon?

Postby hustla_ambition101 » May 7th, 2017, 7:40 pm

Somebody needs to exit from under their rock......ttps adapting....slowly but surely

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