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M7 - Naas/Newbridge Bypass Upgrade [Junction 9a now open]

  • 06-04-2012 5:30pm
    #1
    Registered Users Posts: 10,880 ✭✭✭✭ JupiterKid


    Following on from the suggestion of a poster, this thread has been set up to discuss the need for widening the M7.

    The section of the M7 IMO in immediate need (really a backlog need) for widening is the section from the Maudlins Interchange at Naas to the M9 interchange - basically the original 1983 Naas Bypass and half of the 1993 Newbridge Bypass. Is this likely to proceed in the near future?

    Would the central median be wide enough for widening to D3M here? I'm pretty sure it is wide enough on the Newbridge bypass section but I'm not so sure in the case of the Naas Bypass.

    Also, what bridges will need to be demolished and rebuilt? Or would it be more practical to drop the hard shoulder through the existing bridges?

    What about the proposal a few years back to build a new junction at on the Naas Bypass at Osberstown? Will it still go ahead?

    In the longer term, does anyone see a need to widen the M7 to the N7/M8 junction?
    Tagged:


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Comments

  • Banned (with Prison Access) Posts: 25,234 ✭✭✭✭ Sponge Bob


    It may be done in the next 10 years. They should also allow for west <> south movements at that junction or nearby ( a U turn arrangement 1 mile east perhaps) as part of the project.


  • Registered Users Posts: 7,476 ✭✭✭ ardmacha


    In the longer term, does anyone see a need to widen the M7 to the N7/M8 junction?

    No. Traffic volumes in the Portlaoise area are only about 20k/day.
    While the economy will recover, huge volume increases in a €2/litre era don't seem all that probable.


  • Closed Accounts Posts: 17,738 ✭✭✭✭ corktina


    there would be far more capacity if people would keep left! I don't think the traffic levels are particularly high even with the combined M7/8/9 and local traffic

    I doubt we will have any money for this for some years in any case, but it would be logical even if not top priority.


  • Registered Users Posts: 627 ✭✭✭ JeffK88


    There is a tender out for this stretch of road on etenders so its planned to make some kind of start to it in the coming 5 yrs i would guess. Thats if we don't default by that to time !


  • Registered Users Posts: 4,046 ✭✭✭ AugustusMinimus


    corktina wrote: »
    there would be far more capacity if people would keep left! I don't think the traffic levels are particularly high even with the combined M7/8/9 and local traffic

    I doubt we will have any money for this for some years in any case, but it would be logical even if not top priority.

    I'll add to this further.

    If you make this section of road 3 lane, it will be completely wasted by having middle lane hoggers essentially reverting it to being a 2 lane road.

    Proper policing of our motorways in terms of correct lane usage would go a massive way in adding capacity to the system.


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  • Closed Accounts Posts: 419 ✭✭ Dirigent


    +1 Until their is a liberal doling out of penalty points to the Middle Lane Morons you get on all 3 lane roads, there's no point in spending huge money in widening them.


  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 61,052 Mod ✭✭✭✭ L1011


    Proper policing of our motorways in terms of correct lane usage would go a massive way in adding capacity to the system.

    Except in this case, the road is at capacity regardless and there are huge delays caused every evening due to people who ARE using the correct lanes having to merge over to handle the reduction.


  • Banned (with Prison Access) Posts: 25,234 ✭✭✭✭ Sponge Bob


    Capacity for 2 lanes is 50k-60k a day and by that measure the M7 needs three lanes around and west of Naas while the M4 needs 3 lanes as far as Maynooth.

    Sure start with the M4, smaller job. :D


  • Registered Users Posts: 4,980 ✭✭✭ Chris_5339762


    What would the M11 need?? Apart of course from a massive rebuild of M50/M11 and some form of collector/distributor setup to avoid weaving with the Bray North junction.


  • Registered Users Posts: 27,296 ✭✭✭✭ _Kaiser_


    Just a thought...

    Before ye get too carried away complaining about "middle lane morons", consider this scenario:

    You join the M50 only to have to slow at the bottom of the ramp as the guy in front drops to between 60-80 km/h.

    Meanwhile there's a truck rapidly bearing down on you at 80-90 in the left lane (lets call it lane 1) that you're trying to merge into

    So you finally get into Lane 1, and the guy in front of you has now accelerated to maybe 80 so you look to Lane 2 - there they're doing maybe 80-90

    Into Lane 2 (the middle lane) and by now you're approaching the next exit. Suddenly all hell seems to break loose as drivers start braking/cutting across each other and weaving from Lane 3-1/0 (0 being the exit/off-ramp) or from 1-2 to get around these people - so you move to Lane 3

    Here at least you only have to worry about 1 lane of idiots to your left (well, that and the inevitable A4/BMW driver trying to get into your back seat.. or increasingly 20-30 year old women in hatchbacks) so you stay put as you pass the exit and the chaos starts again on the far side.

    When you consider that we live in a country where we have ads on the TV trying to teach people things that they should know before they ever get behind the wheel of a car - and that are really not much more than common sense - then the above muppetry isn't surprising really, but personally - and especially given the lack of enforcement beyond camping out on dual-carriageways to catch people doing 5km over an arbitrary (often nonsensical) limit - I'll always put the safety of myself, any passengers and my car first, and if that means driving between lanes 2 and 3 in the above scenario then that's what I'll do.


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  • Closed Accounts Posts: 17,738 ✭✭✭✭ corktina


    The whole problem is the result of years of allowing people to just sit into a car without lessons or a proper license. Most Irish Drivers don't know you should be planning ahead as far as you can see and only look at the bit of road in front of their bonnet.


  • Closed Accounts Posts: 1,735 Irish and Proud


    corktina wrote: »
    The whole problem is the result of years of allowing people to just sit into a car without lessons or a proper license. Most Irish Drivers don't know you should be planning ahead as far as you can see and only look at the bit of road in front of their bonnet.

    I see your point - as a newly qualified driver, it goes without saying that you should always plan ahead - such is particularly pertinent on motorways. I frequently wonder if all motorists qualified before the widespread introduction of motorways should be made do a theory test with particularly stringent questions concerning motorways. Line discipline would be a particular concern for me.

    Regards!


  • Closed Accounts Posts: 4,057 ✭✭✭ Tragedy


    How many people in this thread saying 3 lanes is pointless because of middle lane hoggers - have actually driven the M7 at peak times? Or even the m50? All three lanes are full, not just the two closest to the median.

    In peak traffic people seem to use the lanes better.


  • Registered Users Posts: 7,464 ✭✭✭ munchkin_utd


    the peak traffic count on this road is 3000 vehicles in one direction (so citybound in the morning, countrybound in the evening)

    Per minute thats 50cars per second passing a point, or 25 vehicles per lane.
    Or each vehicle is 2.4 seconds apart.
    The safe distance between vehicles is approx 2 seconds so this road is approching its limit, but hasnt reached it.

    So essentially, for the current traffic levels there is not an urgent need for an extra lane on the 2 lane section of the M7 at Naas.

    Traffic jams could be reduced by dynamic traffic management, i.e. reduce the limit to 60 or 80km/h thus reducing the braking distances and allowing more cars fit on the road safely (also reduces jams as theres less braking at lower speeds and thus the chain effect that causes unexplainable jams)

    The utterly inadequate interchange to the M9 which makes the whole section up to the interchange completely disfunctional is another question.


  • Registered Users Posts: 7,464 ✭✭✭ munchkin_utd


    further to my post above proving theres no need for an upgrade based on traffic levels, I've done some calculations on what effect a (dynamic) speed limit would have to your journey time on the 14km section between Naas and the M9 interchange
    speed km/h duration min
    60 14
    80 10.5
    100 8.4
    120 7
    After an upgrade like the m50 with narrower lanes you would probably see a max of 100km/h so thats the reference of what the NEW road could deliver. The days of 120km/h will be over if the new road is built!

    Should the current road get a dynamic limit at peak times of 80kmh you loose only 2min on a crowded but well managed 2 lane compared to a faster flowing 100km/h 3lane over the 14km.

    Should the current road get a dynamic limit at peak times of 60kmh you loose only 4min 40sec on a crowded efficient 2 lane compared to a 100km/h 3lane.


  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 61,052 Mod ✭✭✭✭ L1011


    The utterly inadequate interchange to the M9 which makes the whole section up to the interchange completely disfunctional is another question.

    If you think that interchange is what's causing the problems; its clear you don't actually know the road...

    A VSL would be pissing money down the drain as it would need widening a tiny amount of time later *anyway*.


  • Registered Users Posts: 8,781 ✭✭✭ Carawaystick


    the peak traffic count on this road is 3000 vehicles in one direction (so citybound in the morning, countrybound in the evening)

    Per minute thats 50cars per second passing a point, or 25 vehicles per lane.
    Or each vehicle is 2.4 seconds apart.
    The safe distance between vehicles is approx 2 seconds so this road is approching its limit, but hasnt reached it.

    So essentially, for the current traffic levels there is not an urgent need for an extra lane on the 2 lane section of the M7 at Naas.

    Traffic jams could be reduced by dynamic traffic management, i.e. reduce the limit to 60 or 80km/h thus reducing the braking distances and allowing more cars fit on the road safely (also reduces jams as theres less braking at lower speeds and thus the chain effect that causes unexplainable jams)

    The utterly inadequate interchange to the M9 which makes the whole section up to the interchange completely disfunctional is another question.

    I think there are several flaws in your theory, but it's not fatal.
    First the peak traffic is sampled per hour, not per second or min like you use earlier. I'd bet the traffic is sampled in a clock face fashion, so you have 3000 vehicles from 5-6 pm and from 6-7pm ( say)
    but the peak is the hour from 5:30 to 6:30 when you could have 4000, and only a 1000 in the half hours from 5-5:30 and 6:30 - 7
    You don't have the data to see the actual flow, or the nra haven't published it

    Then you change between vehicles and cars. Articulated lorries will take more time to pass a point, and will require a greater breaking distance, and are limited in speed compared to cars.
    Another point is that coaches are now allowed overtake on Motorways but restricted to 100 ( I think this is the law, it's definitely the practise!)

    Lastly you neglect the effect of standing waves forming, which in heavy traffic are self sustaining, and cause delays long after the incident creating the standing waves has passed by.

    Even with obeyed lower limits( and the temporary ones on the M50 and M1 are completely ignored), if you have a distracted driver breaking hard and slowing down will set up the beginnings of a standing wave.

    I saw an american guy with a site about traffic standing waves and promoting smooth driving with a java explanation about this.

    On the other hand advances in driver assistance systems such as adaptive cruise control, which have spread down from luxury cars like Lexii to top end Fords and in 15-20 years will be much more widespread, and should help increase the theoretical throughput and might reduce the safe inter vehicle time from the 2 second rule.
    Similarly camera systems will reduce lane excursions and increase safety reducing accident frequency by some amount, in the future, reducing excessive delays caused by crashes and rubbernecking.


  • Registered Users Posts: 846 ✭✭✭ regedit


    I live in Kildare and travel this route 6 days a week. It's s a real problem every evening, especially Fridays. To me, the Naas to Newbridge section has been at capacity for some time now and it is painful to think that a few years ago, they resurfaced and widened the road when for very little money, they could have added a third lane. It has become the norm that when traffic at around the ball is particularly heavy, cars turn into Naas and at the ball roundabout take the slip-road and join the M7 again.
    The other mjor problem is lack of driving tradition/culture in this country. I had a family member ask me a few years ago when N7 was upgrade to three lanes 'Isn't it the case that the left ('slow') lane is designated for trucks and buses'. So, loads of people on the road when it is clear they should not be there.


  • Registered Users Posts: 7,476 ✭✭✭ ardmacha


    Lastly you neglect the effect of standing waves forming, which in heavy traffic are self sustaining, and cause delays long after the incident creating the standing waves has passed by.

    http://www.traffic-simulation.de/


  • Moderators, Science, Health & Environment Moderators Posts: 4,406 Mod ✭✭✭✭ spacetweek


    corktina wrote: »
    there would be far more capacity if people would keep left! I don't think the traffic levels are particularly high even with the combined M7/8/9 and local traffic
    Nah, they are. Click here and use the prev button to get to 2010 figures.
    Lewistown (north of M7/M9 junction): 58k vehicles
    Naas Bypass : 55k vehicles


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  • Registered Users Posts: 18,364 ✭✭✭✭ road_high


    The filter/merge for the M9 on/off the M7 are very inadequate and basically you inevitably get stuck behind some nervous driver as you join the M9 southwards from the M7. This causes traffic to back up and slow for miles as it has a kind of domino like effect.


  • Closed Accounts Posts: 1,735 Irish and Proud


    mfitzy wrote: »
    The filter/merge for the M9 on/off the M7 are very inadequate and basically you inevitably get stuck behind some nervous driver as you join the M9 southwards from the M7. This causes traffic to back up and slow for miles as it has a kind of domino like effect.

    There was a tender notice back in February concerning the construction of an additional lane at the M7/M9 merge.

    Regards!


  • Moderators, Science, Health & Environment Moderators Posts: 4,406 Mod ✭✭✭✭ spacetweek


    There was a tender notice back in February concerning the construction of an additional lane at the M7/M9 merge.

    Regards!
    This lane is now complete.


  • Banned (with Prison Access) Posts: 27 ✭✭✭ Spurtacus


    I commute Carlow to Naas everyday so I'm well familiar with the road.
    It definitely hits capacity on Monday mornings northbound & Friday evenings southbound for obvious reasons.

    Outside this the main issue is the outer lane essentially being full, nobody pulls back in after overtaking as you'll soon be behind a truck doing 90kph & you're trapped.
    People get pissed off not being able to pull out & eventually burst out into tiny gaps.
    This causes brake lights in the overtaking lane which feeds back through the domino effect, 1km back the outside lane is stopped & the inside lane begins undertaking.

    It's a gas stretch of road.


  • Banned (with Prison Access) Posts: 378 ✭✭ Quickelles


    Spurtacus wrote: »


    Outside this the main issue is the outer lane essentially being full, nobody pulls back in after overtaking as you'll soon be behind a truck doing 90kph & you're trapped.

    They should do what they do in Germany (maybe elsewhere??) and restrict trucks to the inside lane over this stretch.


  • Closed Accounts Posts: 68 ✭✭✭ pipie


    I believe a lot of the heavy traffic at peak times is due to relativity small exits slips where traffic is almost out the main lanes, people try to slow down to slot into the exit a gradual slow down on the lanes behind occurs.

    So...IMO as well as real policing of lane hoggers and the addition of a third lane - Large multi lane slips should also be considered.
    Basically - getting traffic off the moterway as quickly as possible is bound to lead to freer motoring lanes..


  • Registered Users Posts: 7,476 ✭✭✭ ardmacha


    They should do what they do in Germany (maybe elsewhere??) and restrict trucks to the inside lane over this stretch
    .

    Trucks are restricted to the left lane, they just don't enforce it (as usual).


  • Banned (with Prison Access) Posts: 378 ✭✭ Quickelles


    ardmacha wrote: »
    .

    Trucks are restricted to the left lane, they just don't enforce it (as usual).

    I think on some stretches in Germany (from memory) trucks overtaking at all is banned - they can't move into the overtaking lane at all.

    That's not the law here.


  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 61,052 Mod ✭✭✭✭ L1011


    Quickelles wrote: »
    I think on some stretches in Germany (from memory) trucks overtaking at all is banned - they can't move into the overtaking lane at all.

    That's not the law here.

    It is the law here. Trucks cannot use the outermost lane of a motorway since 1997:

    http://www.irishstatutebook.ie/1997/en/si/0182.html#zzsi182y1997a33

    amended for increased motorway speed limit:

    http://www.irishstatutebook.ie/2012/en/si/0074.html

    One thing of note is that the coach speed limit on motorways is now 100, so they are allowed in the outermost lane.


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  • Registered Users Posts: 7,476 ✭✭✭ ardmacha


    That's not the law here.

    Sadly, many truck drives seem as ill-informed about the law as you.


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