N3 realignment - South Africa

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booshank
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N3 realignment - South Africa

Post by booshank »

Here's a big scheme that is expected to start in 2013 and take three and a half years to complete: the realignment of about 110km of the N3 between Warden and Keeversfontein.

This will eliminate the last non-grade separated part of the N3 on the whole route between Johannesburg and Durban (Johannesburg-Villiers and Keeversfontein to Durban is freeway while Villiers to Warden has been built as one carriageway of a future freeway with overbridges etc built to accommodate the second one).

The reason for the realignment is that the existing road suffers from excessive gradients and poor alignment standards especially at Van Reenens Pass where it crosses the Drakensberg. This coupled with the unusually high proportion of heavy vehicles using the road (around a third) makes it an accident black spot. For the steepest 7km of the pass vehicles of 16t or more are restricted to lane one as a safety measure and with a speed limit of 60km/h (other vehicles 80km/h). Although the road has been widened to S4, the mountainous terrain makes it impossible to improve the gradients or tight curves.

The N3TC consortium that has a 30-year concession on this section of road has a contractual obligation to open an alternative route within 6 months of traffic volumes at Van Reenen reaching 13 900 ADT. Given recent ADT figures, it is predicted work will need to start in 2013 to open in 2017.

Their plan is to realign the N3 through De Beers Pass to a much higher standard - a design speed of 120km/h, gradients of no more than 5% and curves with a radius of no less than 700m (with 1200m desirable).

More information can be found here: Final Scoping Report – 8 February 2011

There's also a biker's video of Van Reenens Pass on Youtube that shows the gradients and large numbers of heavy vehicles: http://www.youtube.com/watch?v=5dQiVaVzFiM
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Re: N3 realignment - South Africa

Post by Vierwielen »

An interesting project.

As a child, I lived in Colenso and the N3 passed through the town, linking Durban and Johannesburg via Ladysmith, Newcastle and Standerton, bupassing the Orange Free State completely, crossing to the Drakensberg via a circuitous route at Majuba.

During my teens, the route via Ladysmith to Johneesburg was rerouted via van Reenens pass and then followed the current route via Harrismith and Warden. This route was renamed the N3 in recent years.

The new route will run between the two routes and by the time it is finished, very little of of original Durban-Johannesburg route will be anywhere near the new route - most of it will be 10 km or more from the original route.
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Re: N3 realignment - South Africa

Post by booshank »

Was that when part of the present N3 was numbered N16, as in this map: The Tourist in South Africa 1965-66? Incidentally, this probably explains why there is now no N16.

I think the old N3 route at Colenso is now numbered as the R103 as normally when a national road is significantly realigned the old alignment is renumbered as a regional road 100 higher, which is quite a neat convention.

This proposed De Beers pass realignment will be a very major project to build a freeway through the Drakensberg - nothing like it has been done in South Africa yet.
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Re: N3 realignment - South Africa

Post by signol »

Good, the last section of single carriageway is to go! Last year we drove up to the FS from Durban, up Van Reenan's pass and down Oliveershoek Pass. Spectacular, but plenty of slow trucks climbing up it, and no room to enlarge there.

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Vierwielen
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Re: N3 realignment - South Africa

Post by Vierwielen »

booshank wrote:Was that when part of the present N3 was numbered N16, as in this map: The Tourist in South Africa 1965-66? Incidentally, this probably explains why there is now no N16.

I think the old N3 route at Colenso is now numbered as the R103 as normally when a national road is significantly realigned the old alignment is renumbered as a regional road 100 higher, which is quite a neat convention.

This proposed De Beers pass realignment will be a very major project to build a freeway through the Drakensberg - nothing like it has been done in South Africa yet.
That is certainly the map that I recognised. Our family left Colenso in 1968 and I left South Africa in 1978.
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Re: N3 realignment - South Africa

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signol wrote:Good, the last section of single carriageway is to go!
Actually it looks like single carriageway will remain between Villiers and Warden, albeit grade separated S4.

I can't really see the sense in building that section to that standard. S4 is not especially safe for the high speeds encouraged by long straight roads and grade separation. If the road is ever upgraded it is likely to be to D2 with hard shoulders (the standard of the freeways either side of it). The existing carriageway is therefore wider than is needed for one carriageway of the planned end-state, so the design isn't even a logical first step from that perspective.

It would have made more sense to build the road to D2, either with a narrow central reservation and concrete barrier, or as two widely separated carriageways. Either option would have only been slightly more expensive than the current layout, and would have been far closer to 'complete' (there would have been the option to add hard shoulders at a later stage if necessary).

It sounds like the new upgrade will be built to divided highway standard, which is a positive move.
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Re: N3 realignment - South Africa

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jackal wrote:
signol wrote:Good, the last section of single carriageway is to go!
Actually it looks like single carriageway will remain between Villiers and Warden, albeit grade separated S4.

I can't really see the sense in building that section to that standard. S4 is not especially safe for the high speeds encouraged by long straight roads and grade separation. If the road is ever upgraded it is likely to be to D2 with hard shoulders (the standard of the freeways either side of it). The existing carriageway is therefore wider than is needed for one carriageway of the planned end-state, so the design isn't even a logical first step from that perspective.

It would have made more sense to build the road to D2, either with a narrow central reservation and concrete barrier, or as two widely separated carriageways. Either option would have only been slightly more expensive than the current layout, and would have been far closer to 'complete' (there would have been the option to add hard shoulders at a later stage if necessary).

It sounds like the new upgrade will be built to divided highway standard, which is a positive move.
I'm not sure what the thinking behind building such single-carriageway grade separated roads is, but they are not especially uncommon and usually like this example they have room left for the other carriageway. However the official term is the tautological-sounding "undivided dual carriageway" for roads with two lanes in each direction separated by a rumble-strip.

I was also thinking that it will be wider than necessary if it is dualled, but the document speaks of predictions of three lanes per direction being necessary by 2035, which perhaps has something to do with it.

On the other hand, many S2 roads without grade separation also have 120 km/h speed limits where traffic is light and in open country with good alignments. I don't think this should be inherently much more dangerous than the 60 mph NSL on roads in the UK that are usually busier and with poorer forward visibility, alignment etc.
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Re: N3 realignment - South Africa

Post by signol »

In other areas of SA, thinking specifically of the N2 north of Durban, S4 has been remodelled into D2 with a narrow central reservation with cable barriers. Could this be the type of improvement envisaged here?

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Re: N3 realignment - South Africa

Post by Vierwielen »

jackal wrote:
signol wrote:Good, the last section of single carriageway is to go!
Actually it looks like single carriageway will remain between Villiers and Warden, albeit grade separated S4.

I can't really see the sense in building that section to that standard. S4 is not especially safe for the high speeds encouraged by long straight roads and grade separation. If the road is ever upgraded it is likely to be to D2 with hard shoulders (the standard of the freeways either side of it). The existing carriageway is therefore wider than is needed for one carriageway of the planned end-state, so the design isn't even a logical first step from that perspective.

It would have made more sense to build the road to D2, either with a narrow central reservation and concrete barrier, or as two widely separated carriageways. Either option would have only been slightly more expensive than the current layout, and would have been far closer to 'complete' (there would have been the option to add hard shoulders at a later stage if necessary).

It sounds like the new upgrade will be built to divided highway standard, which is a positive move.
When I was last in South Africa, many roads were single carriageway in either direction, but with a VERY large hard shoulder. Pedestrians, donkey carts and cyclists used the hard shoulder and motorists would move over onto the hard shoulder to allow another vehicle to pass.

I might be wrong, but this style of construction, which was certainly widely used in 1997, two years after the fall of Apartheid, might well have been designed to allow the army to travel three abreast in case of emergency, and still leave one lane open for on-coing traffic. Only the two central lanes would have full standard foundations with the hard shoulders having a much lower standard, thereby reducing costs. (This is only my theory and I have no means of substantiating it).
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Re: N3 realignment - South Africa

Post by jackal »

South African shoulders, of varying degrees of hardness, are a huge topic in themselves, as they seem to be much more common and varied than in other countries.

I have seen the wide hard shoulders you describe, but a kind of wide gravel shoulder seems to be more common, at least now. I wondered if this was provided for the high levels of walkers one sees next to (or on!) South African trunk roads, but perhaps it has a military purpose. In some cases it might even be a deteriorated version of the weak-foundationed hard shoulder you mention.
booshank wrote:I was also thinking that it will be wider than necessary if it is dualled, but the document speaks of predictions of three lanes per direction being necessary by 2035, which perhaps has something to do with it.
This seems sensible until one considers a further point: if volumes in 2035 would need a D3M, surely volumes before that would need something better than S4?

It also makes it hard to make sense of the adjoining sections of D2M (which lack space for extra lanes on the bridges), unless these are significantly older.
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Re: N3 realignment - South Africa

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jackal wrote:I wondered if this was provided for the high levels of walkers one sees next to (or on!) South African trunk roads, but perhaps it has a military purpose. In some cases it might even be a deteriorated version of the weak-foundationed hard shoulder you mention.
Could well be - there are a lot of pedestrians even in places they are banned from, for example walking alongside or crossing freeways. They have the same restrictions on pedestrians as UK motorways, but many people ignore the laws especially near informal settlements (squatter camps). It is common to see fences and barriers erected alongside roads have had holes cut in them to allow people to cross even where pedestrian bridges are nearby. I have even seen a hole burrowed under the concrete crash barrier in the middle of the N2 between Cape Town and Somerset West.

It also makes it hard to make sense of the adjoining sections of D2M (which lack space for extra lanes on the bridges), unless these are significantly older.
I think there is space for extra lanes where bridges cross the freeway (in the vegetated median), but AFAIK it is not common practice to build bridges that carry the freeway carriageways themselves wider than necessary to allow for future widening - instead they are widened when the freeway is widened. You can see this here where the Kuils River Freeway is being widened by filling in the gap that used to exist between the individual bridges that carried the carriageways. If you look underneath you can see the third element to the bridge that has just been built, similar but not identical to the older outer pair.

You are right that those sections are much older though - as far as I know construction started in 1971 and all or at least most of the freeway sections were finished in the 1970s. The scoping report speaks of the proposed De Beers Pass alignment being planned to be built in the 1970s too but put on hold in 1974. This makes me think that the whole thing from Johannesburg to Durban was originally going to be built as freeway in the 70s, but was left incomplete because of the economic crisis at the time. The Villiers-Warden S4 section is newer, around 10-15 years old I think.
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Re: N3 realignment - South Africa

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I've had a little look into this and construction of the N3 freeway has been a lengthy, stop-start affair. The first section, in the outskirts of Durban, was built in 1954 as a by modern standards sub-standard freeway (probably the first in South Africa).

In 1971 work started with the intention of upgrading/realigning the whole road to freeway standard between Johannesburg and Durban. By 1977 construction had reached from Durban north to Exit 194 (R74) and from Johannesburg south to Heidelberg. After that, economic problems halted work.

In 1987 another 50-odd km were built north from the R74 to the present temporary terminus where the road returns to the old alignment, and in 1988 the 1950s alignment in Durban was bypassed (the old road was demoted to M13) by the Mariannhill toll road. In one place, the old and new roads are right next to each other.

Then there was another long wait till 2008 when the section from Heidelberg south to Villiers was built.

Hopefully by its 50th anniversary (2021) the whole of the original 1971 scheme will be realised!
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Re: N3 realignment - South Africa

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booshank wrote:I've had a little look into this and construction of the N3 freeway has been a lengthy, stop-start affair. The first section, in the outskirts of Durban, was built in 1954 as a by modern standards sub-standard freeway (probably the first in South Africa).

In 1971 work started with the intention of upgrading/realigning the whole road to freeway standard between Johannesburg and Durban. By 1977 construction had reached from Durban north to Exit 194 (R74) and from Johannesburg south to Heidelberg. After that, economic problems halted work.

In 1987 another 50-odd km were built north from the R74 to the present temporary terminus where the road returns to the old alignment, and in 1988 the 1950s alignment in Durban was bypassed (the old road was demoted to M13) by the Mariannhill toll road. In one place, the old and new roads are right next to each other.

Then there was another long wait till 2008 when the section from Heidelberg south to Villiers was built.

Hopefully by its 50th anniversary (2021) the whole of the original 1971 scheme will be realised!
In the late 1950's the only sections of dual carriageway were between Durban and Pietermaritzburg. The N3 itself went via Newcastel and Majuba and did not touch the Free State and I think that part of the Transavall sector might have been all-weather - I certainly remember seeing roadworks for quite a long distnace which suggsted to me that it was getting tarmac.

During the 1960's I remeber the building of the Pietermaritzburg bypass and the dualling up to Mooi River (I used to hitch-hike along that section between home and university). At the same time the N3 was rerouted through the Free State and down van Reenen's Pass.

We moved from Natal in 1969 and I left SA in 1978 so I have not followed developments since then.
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Re: N3 realignment - South Africa

Post by booshank »

Sorry, I forgot that part of what is now the N3 used to be numbered N16 and also I did not know that the Pietermaritzburg bypass was built in the 1960s as I am not old enough to remember and have been trying to piece it together from various maps and other publications and date plaques.

Here's a 1965 map:-

http://farm6.static.flickr.com/5181/555 ... 1eaf_b.jpg

As you can see there has been a lot of renumbering, some of it for unclear reasons eg the present N7 being numbered N11 in 1965, with the modern N11 on the other side of the country. Others make more sense as rationalisations such as merging the old N13 into the N12. Some numbers have been recycled but there is now no N16. It also makes me wonder whether the other missing number (N15) was ever used.
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Re: N3 realignment - South Africa

Post by booshank »

As a little aside, this probably also explains a small but puzzling anomaly in road numbering in the Cape. There, the R101 branches off the R102 at Bellville when you might expect it to be the other way round as the lower number should take priority.

However, the 1965 map shows what is now the southern end of the N1 numbered N9. Presumably when the present N1 alignment was built in the Cape (then numbered N9) the old alignment was numbered R109. R102 would have taken priority over R109, but when *9 was changed to *1 the western end of that regional road was not swapped over to reflect the new priority.
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Re: N3 realignment - South Africa

Post by signol »

booshank wrote:(the old road was demoted to M13) by the Mariannhill toll road. In one place, the old and new roads are right next to each other.
I've just come back from visiting the in-laws, they live on Oxford Rd (scroll to the left of the Google map link) sandwiched between the 2 freeways.

On a previous visit, we took a stroll through the nature reserve, which can't have been that important as they built a huge freeway viaduct through the middle of it:

Image

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Re: N3 realignment - South Africa

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signol wrote:
booshank wrote:(the old road was demoted to M13) by the Mariannhill toll road. In one place, the old and new roads are right next to each other.
I've just come back from visiting the in-laws, they live on Oxford Rd (scroll to the left of the Google map link) sandwiched between the 2 freeways.

On a previous visit, we took a stroll through the nature reserve, which can't have been that important as they built a huge freeway viaduct through the middle of it:

Image

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Great photo, thanks for sharing! I guess that must be under here
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Re: N3 realignment - South Africa

Post by Vierwielen »

booshank wrote: On a previous visit, we took a stroll through the nature reserve, which can't have been that important as they built a huge freeway viaduct through the middle of it:

Image
The nature reserve might well have been a long narrow one following the river valley. It did very little damage to the ecostructure - of course I don't know how much damage was done while it was being built, but in sub-tropical areas, places like that recover quite quickly.
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Re: N3 realignment - South Africa

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booshank wrote:
Great photo, thanks for sharing! I guess that must be under here
That's the spot.
Here is the entrance to the nature reserve.

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Re: N3 realignment - South Africa

Post by signol »

I'm currently out in SA again, here are a couple of pictures of the old N3 (current M13) around Pinetown heading inland. You can see why it was bypassed, with narrow curves on a steep hill, short sliproads and plenty of frontages.

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Fields Hill climbing out of Pinetown
Fields Hill climbing out of Pinetown
Through Kloof
Through Kloof
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