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Ramp metering

  • 29-05-2014 4:34pm
    #1
    L1011
    Registered Users, Registered Users 2 Posts: 71,190 ✭✭✭✭


    The ramp meters at the Port Tunnel are actually in use this evening - doing about three or vehicles per change rather than the standard 1 done abroad

    Is this abnormal or have the NRA started doing this regularly? Ramp meters would help on the N4 inbound and probably other roads (N40 and maybe M50) if they do a rollout.


Comments

  • #2
    Carawaystick
    Registered Users, Registered Users 2 Posts: 8,779 ✭✭✭Carawaystick


    I have no idea what ramp meters are.


  • #3
    L1011
    Registered Users, Registered Users 2 Posts: 71,190 ✭✭✭✭L1011


    Carawaystick wrote: »
    I have no idea what ramp meters are.

    Would have thought it was a well known term in road technology:

    http://en.wikipedia.org/wiki/Ramp_meter

    Allows a controlled number of vehicles to enter at each onramp per time period to allow better spacing, higher speeds and hopefully fewer crashes due to less chance of people slamming on / reaching the end of a ramp and not getting in etc.

    I've seen them used on a pure timer system, as in one green per 20 seconds, or on a system which seems to determine long enough gaps in Lane 1

    The Port Tunnel junction on the M50/old M1 is the only place in Ireland with them as far as I know - they generally sit on either green or flashing orange at all times; last night was the first time I ever saw them actually in use. In other countries they usually get turned off entirely when out of use to reduce confusion.


  • #4
    Iwannahurl
    Closed Accounts Posts: 8,156 ✭✭✭Iwannahurl


    Ramp metering is just one method to maximise throughput on existing infrastructure.

    https://www.youtube.com/watch?v=CX_Krxq5eUI


    https://www.youtube.com/watch?v=8G7ViTTuwno


  • #5
    AugustusMinimus
    Registered Users, Registered Users 2 Posts: 4,564 ✭✭✭AugustusMinimus


    One huge issue on multi lanes roads which causes traffic is speed variances between different drivers.

    Some go well under the limit while some go well over the limit. Some vehicles are electronically limited to 90kph (lorries). Traffic would flow much better if everyone was doing the same speed. It would lead to a more compact usage of each lane and it would avoid phantom tailbacks which are caused by people braking coming up behind slower drivers.

    Another huge issue is simply poor road planning by the NRA and county councils. From about the 1960s onwards, the grid layout of cities has largely been replaced by huge housing estates which might only have 1 entrance and exit onto a road. This leads to very low useable road density to get from point A to point B and leads to huge tailbacks at various critical junctions at rush hours.


  • #6
    Iwannahurl
    Closed Accounts Posts: 8,156 ✭✭✭Iwannahurl


    AugustusMinimus wrote: »
    Another huge issue is simply poor road planning by the NRA and county councils. From about the 1960s onwards, the grid layout of cities has largely been replaced by huge housing estates which might only have 1 entrance and exit onto a road. This leads to very low useable road density to get from point A to point B and leads to huge tailbacks at various critical junctions at rush hours.


    A favourite subject of mine, but I won't indulge in this thread... :)


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  • #7
    Schadenfreudia
    Banned (with Prison Access) Posts: 6,995 ✭✭✭Schadenfreudia


    AugustusMinimus wrote: »

    Another huge issue is simply poor road planning by the NRA and county councils. From about the 1960s onwards, the grid layout of cities has largely been replaced by huge housing estates which might only have 1 entrance and exit onto a road. This leads to very low useable road density to get from point A to point B and leads to huge tailbacks at various critical junctions at rush hours.

    Surely that has nothing to do with the NRA? They didn't even exist in the 60s, 70s, 80s and most of the 90s.


  • #8
    AugustusMinimus
    Registered Users, Registered Users 2 Posts: 4,564 ✭✭✭AugustusMinimus


    Schadenfreudia wrote: »
    Surely that has nothing to do with the NRA? They didn't even exist in the 60s, 70s, 80s and most of the 90s.

    On the whole its mainly County Council and City Corporation's fault. However, of late the NRA has made some very strange errors in the development of the national road network which has meant that traffic has had to travel greater distances or accessed local road network to perform certain manoeuvres.

    M7/M8 junction being a case in point. M8 North to M7 West or M7 East to M8 South is not possible with this junction. The Rossbrien interchange of the M7 and the M20 is also a disaster.

    Plenty more out there I could go through too.


  • #9
    Iwannahurl
    Closed Accounts Posts: 8,156 ✭✭✭Iwannahurl


    Schadenfreudia wrote: »
    Surely that has nothing to do with the NRA? They didn't even exist in the 60s, 70s, 80s and most of the 90s.


    This is the sort of thing the NRA was doing in the first decade of the 21st Century:

    http://www.meathchronicle.ie/news/meathsouth/articles/2008/11/26/33578-angry-residents-say-new-roundabout-cuts-them-off-from-dunshaughlin/print

    http://www.boards.ie/vbulletin/showthread.php?p=65633751


  • #10
    Schadenfreudia
    Banned (with Prison Access) Posts: 6,995 ✭✭✭Schadenfreudia


    Iwannahurl wrote: »
    This is the sort of thing the NRA was doing in the first decade of the 21st Century:

    Hardly hanging offences!

    As for the M7/M8 junction the junction numbers on the M8 suggest they have planned for an M8-west turn.

    All very minor quibbles.


  • #11
    SeanW
    Registered Users, Registered Users 2 Posts: 9,172 ✭✭✭SeanW


    Schadenfreudia wrote: »
    Hardly hanging offences!
    The poster in question obviously feels differently :pac:
    As for the M7/M8 junction the junction numbers on the M8 suggest they have planned for an M8-west turn.
    Yes, it was not built because then you could have people using the M7/M8 for a South > West or West > South move and not paying the toll. Or it might have been a planning issue. The issue might be revisited when the toll contract ends.


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  • #12
    veryangryman
    Registered Users, Registered Users 2 Posts: 5,660 ✭✭✭veryangryman


    SeanW wrote: »

    Yes, it was not built because then you could have people using the M7/M8 for a South > West or West > South move and not paying the toll. Or it might have been a planning issue. The issue might be revisited when the toll contract ends.

    Doubt its the former. The M7-M9 untolled junction has the same issue for M9 north to M7 west traffic


  • #13
    SpaceTime
    Closed Accounts Posts: 9,088 ✭✭✭SpaceTime


    AugustusMinimus wrote: »
    One huge issue on multi lanes roads which causes traffic is speed variances between different drivers.

    Some go well under the limit while some go well over the limit. Some vehicles are electronically limited to 90kph (lorries). Traffic would flow much better if everyone was doing the same speed. It would lead to a more compact usage of each lane and it would avoid phantom tailbacks which are caused by people braking coming up behind slower drivers.

    Another huge issue is simply poor road planning by the NRA and county councils. From about the 1960s onwards, the grid layout of cities has largely been replaced by huge housing estates which might only have 1 entrance and exit onto a road. This leads to very low useable road density to get from point A to point B and leads to huge tailbacks at various critical junctions at rush hours.

    In some of the developments around Cork City that sprung up in the 2000s I've actually heard residents OBJECT to having them interconnected because this would 'put children at risk' and 'devalue my house' by connecting it to a cheaper estate or that it will 'encourage teenagers to hang around' etc etc etc

    Planning here = pandering to the Hyacinth Bucket mentality.

    The result : no urban landscape created, just a load of disjoined housing estates. In some cases you'd shops in the middle of one estate which are inaccessible from the estate next-door without a really long walk.

    It's nothing to do with the NRA though, it's just local authority pandering to snobbery and lacking any vision of what an urban space is.
    AugustusMinimus wrote: »
    On the whole its mainly County Council and City Corporation's fault. However, of late the NRA has made some very strange errors in the development of the national road network which has meant that traffic has had to travel greater distances or accessed local road network to perform certain manoeuvres.

    M7/M8 junction being a case in point. M8 North to M7 West or M7 East to M8 South is not possible with this junction. The Rossbrien interchange of the M7 and the M20 is also a disaster.

    Plenty more out there I could go through too.

    The M7-M8 junction should have also had a flyover to allow traffic to loop back onto the other side without having to drive to Portlaoise.

    They just didn't contemplate that anyone would be driving other than to and from Dublin/Cork/Limerick. Sure what would you be going any other direction for!?

    I think the fundamental mistake made was that the M7/M8 split should have happened much further south which would have created a viable Cork-Limerick motorway route.

    I also kinda wonder with the existing setup, would you not be better building a Motorway from Mitchelstown to Limerick rather than going the old N20 route? Obviously this would annoy Mallow and Charleville though which are probably worth serving by motorway en route if possible.

    I just think it was a shame the M7/M8 setup didn't serve the purpose of that link in the first place.


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