Road engineering

jrar

So, there's been a LOT of road building in this country over the last 15-20 years especially with regard to the motorway network.

I had reason to drive last night on the N7 from junction 8 eastbound and a large section of the M50 - ALL of the overhead gantries warned of "Caution - Surface Water" and yes, it was a wet and windy night so there was a lot of spray etc.

It occurred to me that given how new the roads were in relative terms, and how we live in a country that gets a regular rainfall pretty much all year round, is it an engineering deficit that these roads seem to drain so poorly, and that pools of water giving rise to possible aquaplaning risks ?

Yes, I expect a cloudburst to create a problem with driving conditions via traffic spray, but even average falls of rain (for Ireland) seem to present problems. It might be exacerbated this time of year via leaf fall and drains not being cleared in a timely/regular manner (which is more of an operational/maintenance thing), but I can't help thinking that there appears to be engineering/drainage issues to begin with

loyatemu

it's very noticeable where you from one section of motorway to another, e.g from Bray Bypass M11 (which has all the drainage properties of a field beside the Shannon) and the M50, which is much better.

dave 27

I was driving on this stretch and there was a number of spots that were very flooded and at one point by the red cow before you turn to the northbound lane my whole windscreen was covered for about 2-3 seconds which was very scary.

There is something seriously flawed if this i what we are getting on new motorways

They swapped from using a rougher surface material/finish when they upgraded the M50 from 2lanes to 3. The old surface drained much better. You can see this quite easily on the M11, the new section is smooooooth and quiet and the old section before/after much rougher, and the difference in water dispersion is huge.

jrar

Is it an either or situation - surely the engineering teams within the NRA/councils etc. have the ability to provide both i.e. smoother/quieter roads that still drain efficiently during spells of wet weather ??

The rainfall amount last Sunday was not by any means exceptional, so it doesn't augur well for either this coming Winter, or for harsher /wetter weather events which we're being regularly warned we can expect as a result of climate change etc.

L1011

Newer low noise surfaces are demanded by people living near roads so they're not going to go away

They're using stone mastic asphalt on the M50 at least, as opposed to (I believe) dense graded asphalt on older motorways.


SMA is significantly more durable and a little quieter. The quietest road surface is porous asphalt but it's a lot less durable.


https://www.kilsaran.ie/project/m50-m11-junction-pavement-scheme/

jrar

Appreciate the side discussion on quietness and smoothness of surfaces, but per my original post, I'm still mystified as to why so many of our new motorways seem to drain so poorly ? (and I'm speaking entirely as an ordinary Joe without any engineering experience etc.)

Is it a camber/surface issue ? ....or not having enough culvert/storm drains ?..... or have we ended up building motorways across areas more prone to flooding ?

I know EVERY road has issues at times of heavy rain / cloudbursts but it just seems to be particularly bad on a lot of our motorways

It's because they're using a different road surface that's both quieter and harder wearing, as was pointed out (partially) in 3 posts