[HIGHWAY_PATROL]

Originally Posted by Turbohead

Actually they moved on from speed breakers to the current continuous rumble strips since many cars got rear ended by stopping quickly.

IMO, they've tried everything possible. The current solution given there, IMO, is more than sufficient to warn users to be careful. However, I'm not sure why these trucks continue to lose control. Are our trucks so badly overloaded and under maintained?

As I see it, the only way to save lives in the present situation is to limit the speed of vehicles in that stretch.

I think speed breakers are more effective than rumble strips for that. They could have used more tact in placing the speed breakers to avoid cars getting rear-ended.

If, as you say, even speed breakers are not effective, then perhaps they should only have a single lane for the entire stretch and see if that helps to save lives. Until ofcourse, a better solution is put in place.

It's really heart wrenching to see innocent lives being lost.

[HighOnSpeed]

What a terrible accident! I hate driving through here. And, driving through the Thoppur section is an absolutely nightmare during the holidays, especially during the night. I can easily recollect several close calls and road rage incidents. Almost all the lanes are hogged up by ultra-slow moving trucks(can't blame them though). What really puts me off are those extremely impatient drivers who take the shoulders and abruptly cut through the moving traffic incessantly without any sort of lane discipline. And those rumblers on the curves need to go ASAP! It's so easy losing traction on those if your vehicle is hitting them at high speeds. Of course all the mishaps can be easily mitigated if everyone just followed the speed limits, but we all know that is very unlikely. An alternate route/bypass would do some good.

[Jonathan Arpith]

I believe most of the accidents are due to loaded trucks not sticking to gear 1/2, and not sticking to their lane. So just an (out o the box) idea to control the accidents:
Hire 100 drivers as pilots for the section. Like how pilots are used in shipping around ports/congested waterways.
All trucks will then be driven by the pilot from Toll gate to Thoppur town. The pilots should be trained so that they will only drive in the left lane and only in gear 2.
Buses will then ferry a group of pilots from the bottom to the top. Assuming 2 shifts, the yearly cost would probably be around Rs 10 Crore (Max). As per a news report the toll booth collection was Rs 15.86 Cr per Km (average yearly collection between 2010 and 2021). So this should not be a big expense.

Long term solution would be to build a better alignment.

[RGK]

Originally Posted by binand

Maybe you don't understand the topography here. Salem is at an altitude of ~275m above sea level. Dharmapuri is at ~475m.
There is no one mountain that you can tunnel through and get back to the Salem altitude on the "other side". The Thoppur ghat is not a road that climbs up a mountain on one side and descends on the other.

Noted. I was attempting to explain this one. Used my drawing skills ?!! to understand better. 1. Salem - 275 MSL
2. Ghat starting point. 3. Ghat ending point.

Disclaimer: I'm not a geologist or an infra specialist. Just my POV.

[svsantosh]

Originally Posted by RGK

...a tunnel can maintain the same altitude throughout and even go straight (if possible) ...

Originally Posted by RGK

Noted. I was attempting to explain this one. Used my drawing skills ?!! to understand better. 1. Salem - 275 MSL
2. Ghat starting point. 3. Ghat ending point.

The discussion was around your words 'Same Altitude' - as you can see from your drawing when you move from 275MSL to 475MSL there sure is an incline to deal with - so the 'same altitude' is ruled out.

As to the 'straight' word; I think I understand what you are meaning; bore from base of Thoppur straight to the toll gate (near about) on the top, see my pic, is that what you mean? How much ever impractical and expensive it may be, i feel it will put a great stress on the brakes while coming down, and also load on engine/GB will be too high.

[RGK]

Originally Posted by svsantosh

so the 'same altitude' is ruled out.

Santosh, My POV is to maintain the same altitude from the start to the end of the tunnel. Also, the tunnel can be more than one.

1. The tunnel (can be straight if possible) will be under the Dharmapuri MSL naturally and need to be adjusted on the open highway after completely exiting the ghat zone.
   
2. The inclination need to be very minimal and lengthy.
   
3. After the tunnel exit, the road may look like an open underpass due to the ~200m variance (ghat zone & MSL difference), and can be adjusted after a few kilometers (point no 2).

[ph03n!x]

Originally Posted by RGK

Santosh, My POV is to maintain the same altitude from the start to the end of the tunnel.

...

Not possible, mate. The tunnel will have to be at an inclination coz there is no climb-down after this ghat - the roads become flat-ish till Krishnagiri toll which is about 75 KM away. It is like climbing on to a table-top.

What the tunnel can do is reduce the inclination by increasing/ reducing the inclination in steps - but there is no way this terrain can have a flat tunnel with negligible inclination.

[venkyhere]

i think the fundamental problem with thoppur descent is that it's in TN. That's why it's becoming an engg problem. Had it been KA, they would have installed 10-12 monster (circa 2000s mysore road) concrete humps downhill and be done with it.

[Fawlty]

What about having one more toll plaza where the slope ends? Fix speed limit of 30-40Kmph. Any vehicle that crosses the 2nd toll within a set-time, say inside 10 minutes, will get penalized with 10x toll on the 2nd toll plaza.
Needless to say there should be no tea shops, restaurants, conveniences, places of worship, etc along the way.

[binand]

Originally Posted by RGK

Santosh, My POV is to maintain the same altitude from the start to the end of the tunnel. Also, the tunnel can be more than one.

1. The tunnel (can be straight if possible) will be under the Dharmapuri MSL naturally and need to be adjusted on the open highway after completely exiting the ghat zone.
2. The inclination need to be very minimal and lengthy.
3. After the tunnel exit, the road may look like an open underpass due to the ~200m variance (ghat zone & MSL difference), and can be adjusted after a few kilometers (point no 2).

If I'm not mistaken what you're actually advocating is to build the road so that it climbs the 200m elevation difference over a distance of something like 25 km (from Thoppur to Dharmapuri), drilling through or cutting open the mountain based on local conditions - instead of the current road that makes this 200m climb over just 6 km?

There is no "completely exiting the ghat zone". It is a climb all the way till Hosur/Bangalore. Please, please look at the terrain view. I've even linked to it below.

https://maps.app.goo.gl/M6DeEnwm9CBB4V3QA

[svsantosh]

Originally Posted by RGK

Santosh, My POV is to maintain the same altitude from the start to the end of the tunnel. Also, the tunnel can be more than one.

Either I am not able to understand your POV or My understanding of the word 'Altitude' needs a check.

Per your POV a tunnel from 275MSL to 275MSL will need a solution to lift the cars from under the mountain, no?

[discoverwild]

Originally Posted by RGK

Noted. I was attempting to explain this one. Used my drawing skills ?!! to understand better. 1. Salem - 275 MSL
2. Ghat starting point. 3. Ghat ending point.

Originally Posted by svsantosh

The discussion was around your words 'Same Altitude' - as you can see from your drawing when you move from 275MSL to 475MSL there sure is an incline to deal with - so the 'same altitude' is ruled out.

Originally Posted by venkyhere

i think the fundamental problem with thoppur descent is that it's in TN. That's why it's becoming an engg problem.

Originally Posted by ph03n!x

What the tunnel can do is reduce the inclination by increasing/ reducing the inclination in steps - but there is no way this terrain can have a flat tunnel with negligible inclination.

Originally Posted by Fawlty

Needless to say there should be no tea shops, restaurants, conveniences, places of worship, etc along the way.

Originally Posted by binand

There is no "completely exiting the ghat zone". It is a climb all the way till Hosur/Bangalore. Please, please look at the terrain view. I've even linked to it below.

Originally Posted by sarathlal

Rumbler strips are more often counter productive. If vehicles slow down to 25-35 mph speeds, these strips will rattle the hell out of the vehicle, so most of the times, motorists tend to speed up to 'fly' over them if they see one.

Tagging the people who were discussing the Thoppur Ghat section with updates from the Government. This was shared by one of the party handles.

The Government has proposed and sanctioned an elevated road as follows:

"Realignment of #Thoppur ghat for which the tender bid is finalised and work for new elevated 4 lane from Dharmapuri -Thoppur ghat road start to entry of Salem district for 6.6 kms with a butterfly crossroads flyover at the Dharmapuri/mettur junction to start soon at 756 crores."

This flyover extends past the Thoppur-Metttur-Bhavani intersection where the road elevation is higher after the bridge which was the spot of the accident.

[venkyhere]

Originally Posted by discoverwild

Tagging the people who were discussing the Thoppur Ghat section with updates from the Government. This was shared by one of the party handles.

The Government has proposed and sanctioned an elevated road as follows:

"Realignment of #Thoppur ghat for which the tender bid is finalised and work for new elevated 4 lane from Dharmapuri -Thoppur ghat road start to entry of Salem district for 6.6 kms with a butterfly crossroads flyover at the Dharmapuri/mettur junction to start soon at 756 crores."

This flyover extends past the Thoppur-Metttur-Bhavani intersection where the road elevation is higher after the bridge which was the spot of the accident.

Thank you for this update.
Whenever I've read/watched news about an accident coming down the thoppur ghat,
(1) it's a truck, loaded, most probably overloaded.
(2) it's always in the zone indicated by the orange arrows in the below pic (currently there are a series of rumblers that we can see in satellite view)
(3) There are two giant back to back "S" curves (elevation drop is a lot) immediately before this orange zone. Currently the second S (the tail of which can be seen in below pic) is littered throughout with rumblers, just like the ones the orange arrows are pointing at.

So the issue is almost surely brake fade (if we eliminate stupidity like riding down in neutral, despite all the loudspeakers and rumblers) , and it's exacerbated by overloading. However, the root cause is not the zone shown in these pics but the two S's preceding it, occurring back-to-back, without allowing the brakes to be let off for even a few seconds.

And the catalyst that exposes the above root cause and creates a perfect accident scenario, is, ironically, the 'solution' implemented here, in the form of those rumblers in the zone shown by the orange arrows. These rumblers will cause smaller vehicles to slow down (they have weaker suspension and smaller wheels afterall, and they aren't carrying several Tonnes to have their brakes faded while coming down the two S's, so they will all have had enough of the epileptic-fit like shaking their cars underwent through the last 'S', and to not repeat those fits through these orange zone rumblers) where they all hit their brakes in this orange zone --> so here is established a situation where a loaded truck who has cooked his brakes through the two S's is coming down and wants to simply coast through these orange arrows, but is forced to apply brakes again. And during this condition, not only does he have cooked brakes, his cargo is still carrying a laterally outward momentum from the just finishing second S curve's tail, because he hasn't got enough time to 'straighten' and tidy everything up. This is like a perfect storm - ineffective brakes and momentum with a lateral component, the ideal scenario for a jackknife.

IMHO, the easiest and cheapest solution will be to build a truck-only "flyover" that ramps up and then comes down (essentially a 'runaway truck ramp') and rejoins the existing path a bit further down the line. The downramp of this separate flyover, can be extended for however long it needs to be, perhaps all the way until after the Mettur turnoff. This way, the exit of the second S can be less stressful for the truck and the driver, there is no immediate need to hit the brakes again, and the lateral momentum of his cargo can gradually ease back into the forward direction, while climbing up this new flyover/ramp. No vehicles other than trucks on this 'flyover'/runaway-ramp either.

I don't understand why the solution has to be 6.6km long and incur so many crores; which will not just cost the exchequer a lot, but also cause huge delays during the construction phase, owing to the length and scale of such a project.

[discoverwild]

Originally Posted by venkyhere

it's a truck, loaded, most probably overloaded.

99% of the trucks running in the country are overloaded. The few that are not are those long haulers carrying cars and windmills.

(2) it's always in the zone indicated by the orange arrows in the below pic (currently there are a series of rumblers that we can see in satellite view)

Have been driving this route for the last 33 years. Before the 4-laning was introduced and it was a single carriage way, the accidents used to happen at the S-curves. The 4-laning moved the accident spot further down.

IMHO, the easiest and cheapest solution will be to build a truck-only "flyover" that ramps up and then comes down

A simple solution is to separate cars and bikes into a single lane and create a separate 2-3 lane for trucks and buses along the entire downward slope.

The current temporary barricades are insufficient and both cars and trucks intermingle at various points causing trucks to brake more often than required, leading to brake fade.

I don't understand why the solution has to be 6.6km long and incur so many crores; which will not just cost the exchequer a lot, but also cause huge delays during the construction phase, owing to the length and scale of such a project.

Simpler solutions are cheaper and do not evince interest from politicians because the "percentages" are miniscule. That's why we have grand plans of a 60 hkm tunnel project in Bangalore costing 60,000 Crores, rather than enhancing public transport costing a few 100 Crores. It's the same across all parts of the country.

[itwasntme]

Originally Posted by discoverwild

The Government has proposed and sanctioned an elevated road as follows:

"Realignment of #Thoppur ghat for which the tender bid is finalised and work for new elevated 4 lane from Dharmapuri -Thoppur ghat road start to entry of Salem district for 6.6 kms with a butterfly crossroads flyover at the Dharmapuri/mettur junction to start soon at 756 crores."

Better late then never, and I am glad to see this:

• It will provide a more modern alignment + a gentler grade.
• From the plans, it also looks like it will not replace the current alignment but be an all-new elevated one, with the advantage that there will be two separate routes through that section.
• Again, the impact of a greenfield alignment will be much less on existing traffic than a brownfield one.
• Once complete, traffic management can be improved with possible segregation over-sized traffic.
• It will also somewhat 'future-proof' that section which already cannot handle peak holiday / weekend traffic.
• Remove that dangerous Thoppur town crossroads (if I recollect correctly).

At the end of the day, we are talking about a relatively small hilly section to be modernized. NHAI has done 100x times more across India.