HQDC vs 2+2

AugustusMinimus

Just wondering if anyone has the average cost per km of HQDC vs 2+2

I know that outside of some remaining schemes such as the M20, the majority of new road builds going forward will be 2+2. Are they value of money instead of just building HQDC?

The main difference as I see them.

No breakdown lane / hard shoulder. HQDC much safer in this respect.
Corner radii can be tighter on 2+2
Flyover bridges are less expensive
Less land take for 2+2

Personal view is that all inter urbans including N24 and N25 should be HQDC from the off.

roadmaster

AugustusMinimus wrote: »

Just wondering if anyone has the average cost per km of HQDC vs 2+2

I know that outside of some remaining schemes such as the M20, the majority of new road builds going forward will be 2+2. Are they value of money instead of just building HQDC?

The main difference as I see them.

No breakdown lane / hard shoulder. HQDC much safer in this respect.
Corner radii can be tighter on 2+2
Flyover bridges are less expensive
Less land take for 2+2

Personal view is that all inter urbans including N24 and N25 should be HQDC from the off.

Good Document below on type 2. It says it only cost 10% extra. Cant find any costs for HQDC.

http://www.tiipublications.ie/library/DN-GEO-03059-01.pdf

Now these costs are as rough as you get and for various reasons such as ground conditions and structures are not fair to compare

The original N18 HQDC Ennis Bypass in 2007 cost 190 million for 14km which gives you 13.7 million per Km
The Dromod Type 2 DC Bypass in 2008 cost 84.2 million for 10km which gives you 8.4 million per Km

Id probably take the above with a bag of salt but they where the closest jobs that i could compare

marno21

roadmaster wrote: »

Good Document below on type 2. It says it only cost 10% extra. Cant find any costs for HQDC.

http://www.tiipublications.ie/library/DN-GEO-03059-01.pdf

Now these costs are as rough as you get and for various reasons such as ground conditions and structures are not fair to compare

The original N18 HQDC Ennis Bypass in 2007 cost 190 million for 14km which gives you 13.7 million per Km
The Dromod Type 2 DC Bypass in 2008 cost 84.2 million for 10km which gives you 8.4 million per Km

Id probably take the above with a bag of salt but they where the closest jobs that i could compare

Does that cost for the Ennis bypass include the cost of the N85 section which is quite significant ?

marno21

Firstly, there is a 30% increase in landtake for Type 1 vs Type 2.

Secondly, all junctions on Type 1 are grade separated whereas (unfortunately) roundabout junctions are common on Type 2

Type 1 has a 120km/h design speed vs a 100km/h design speed for a Type 2. This can mean more earthworks to provide gentler curves and less steep gradients.

It's a case by case basis as to what the cost increase is

When 2+2 was introduced as a standard it was planned to have 200km+ of it built by now. Not the minor sections of N3/N4/N17/N21/N69 we have built

roadmaster

I am not a 100% sure but i think you are correct it did include the N85 from what i remember. But like i said in the post above and you have also mentioned it is very hard to compare due to so many variables. At the same time around 2007 Siac and wills completed there section of 20 km of the than N6 HQDC for 90 million which works out at 4.5 million per Km

Carawaystick

Doesn it not depend on the amount of roads that cross the mainline? for hqdc, they are all gs, but for 2+2 they are at grade?