COMHAIRLE CONTAE ÁTHA CLIATH THEAS
SOUTH DUBLIN COUNTY COUNCIL

MEETING OF TERENURE-RATHFARNHAM AREA COMMITTEE (1)

Tuesday, June 10, 2008

HEADED ITEM NO. 3

Greenhills Road QBC

Report on options for bus priority on the Greenhills Road at the Bridge over the M50.

A number of options were assessed as follows 

• Option 1       Bus Lanes in Both Directions 
• Option 2       Bus Lane in Southbound Direction Only 
• Option 3       Bus Lane in Southbound Direction with bus gate in Northbound Direction 

Option 1 consists of constructing pedestrian and cycle facilities on either side of the existing road bridge. Three options were considered in order to achieve this as detailed below 

• Steel Trusses
  • Cost €850,000
• Cantilevered Structures
  • Cost €1,100,000
• Cable Stayed Bridges
  • Cost €1,550,000 

The above costs do not include: 

• Additional strengthening to the existing bridge in order to accommodate two additional lanes
• Traffic Management during construction
• Possible compensation payable to the M50 PPP Company 

Options 2 and 3 involve re-configuring the existing layout on the M50 road bridge, but do not require construction works to be carried out to the structure of the bridge

Options 1 to 3 were modelled using the Transyt software package. The results showed no significant change in average bus speeds when comparing the three options. 

Journey time surveys carried out by South Dublin County Council in April 2008, indicated that the maximum delay at the bridge was 26 seconds in the northbound direction and 1 minute in the southbound direction. 

It is therefore proposed to implement a bus lane in the southbound direction only, with the provision of infrastructure to facilitate the future implementation of a bus gate in the northbound direction should the need arise.