ITEM CMDT7
CABINET MEMBER FOR TRANSPORT – 24 APRIL 2008
DOWNS RD/A40 WITNEY – PROPOSED AT-GRADE ROUNDABOUT
Report by Head of Transport
Introduction
1. This report seeks approval to design and submit a planning application for an at-grade roundabout at the A40/Downs Rd junction in Witney (Annex 1) (download as .pdf file). The report outlines the background to this proposal, the justification for this type of junction and how the scheme would be funded.
Background
2. The need for a junction at this location was set out in a report to the Executive on 16 June 2004 (Annex 2) (download as .doc file). In summary, the main purpose of the new junction would be to provide access for A40 traffic wishing to access the Downs Road industrial area. At present, the lack of a junction in this vicinity means that HGV’s access the area via less suitable routes such as residential roads in west Witney, through Minster Lovell village and along the Burford Road. A new junction would therefore result in a redistribution of traffic movements, in turn delivering a number of knock on benefits across the town in terms of improvements to road safety, congestion, air quality and the street environment.
3. Although the need for the junction was established and agreed at the June 2004 Executive, the study work conducted at the time did not reach a definitive conclusion regarding the type of junction that should be implemented. It was agreed that this would be determined following further assessment work.
Evaluation of Different Options
4. Four different options for this junction have been considered:
· Option 1 - No A40/Downs Road junction (this was used as a base from which to compare the effectiveness of other options); · Option 2 - at-grade roundabout; · Option 3 - grade-separated (east facing slips only); and · Option 4 - grade-separated (all movements).
5. Halcrow were commissioned in 2004 to carry out an evaluation of the above options. Their report concluded that Options 2 and 4 both provide satisfactory solutions in traffic terms. Option 3 was considered to be less suitable as it only catered for traffic travelling to/from the east, with traffic coming from the west still having to travel through Minster Lovell or the Ducklington Lane junction. Oxfordshire Highways have also done some work using more recent traffic data to verify these results and initial indications have suggested that the Halcrow evaluation still stands true, with both options 2 and 4 performing similarly well.
6. Preliminary designs were drawn up for the two preferred options (2 and 4) as part of the Halcrow work in 2004 and a road safety audit was carried out in 2007 based on these designs. The road safety assessment showed that there is in fact minimal difference between the two options. The analysis showed that at the junction itself, an at-grade roundabout could introduce an extra 2-3 accidents per year compared to the grade separated (all movements) option. However it was noted that the accident rates would depend on the detail of the junction design and that the potential for these accidents could therefore be reduced through careful consideration to safety issues at this stage.
7. Since the junction would result in a wider redistribution of traffic flows, the road safety audit also looked at the impacts on the road network around the junction. This evaluation showed no differences between Options 2 and 4.
Cost implications
8. The cost of each option was assessed in 2003 and these estimates have been factored up to November 2007 prices. For all options, the costs include the widening of Downs Road from Range Road to the new junction (including the provision of a new cycle track) to better facilitate HGV movements in both directions. The estimates also include the cost of carrying out an Environmental Impact Assessment (EIA), design and supervision, landscaping, land, utilities, traffic management and a 25% contingency. The table below shows the current cost estimates.
9. There is currently £3.4 million of developer contributions secured towards this scheme. This means that only Option 2 is deliverable as it is the only option that could be fully funded.
Timescales
10. A full Environmental Impact Assessment (EIA) would be needed for this scheme as the area it covers is likely to be larger than 1 hectare in total. The EIA would take at least a year (to allow for a full ecological cycle) and would have to be completed before a planning application could be submitted. An indicative programme for an at-grade roundabout is shown at Annex 3 (download as .xls file).
11. In summary, this programme shows that an at-grade roundabout would take approximately 3 years and 3 months from project initiation to completion (or 2 years if the land required is owned by a collaborative developer). This compares to 4 years and 6 months for a grade-separated junction (reduced to 3 years if the land is owned by a collaborative developer).
Officer comments
12. The at-grade and grade-separated (full movements) options offer the best solutions at this junction, for both movements at the junction and on traffic flows in the wider area. They allow for all movements and will reduce pressure on the A415/Ducklington junction as well as the B4477/A40 junction.
13. The safety audit shows minimal differences between the two options and specifies that the accident rates could be minimised through careful design at the detailed design stage.
14. Based on the funds currently available, the at-grade roundabout option is the only viable option at present. The costs are based on an indicative design carried out in 2003 so detailed design work will be required in order to refine this estimate.
15. The at-grade roundabout offers the shortest implementation period and therefore would offer a fully operational junction at least a year before a grade-separated junction.
How the project supports LTP2 objectives
16. The at-grade roundabout will contribute to the LTP2 objectives by reducing congestion at the A40/Ducklington Rd junction and other junctions around the town; improve accessibility to services and jobs at the industrial parks at west Witney; improve road safety by removing large numbers of HGV’s from residential roads and could help improve air quality and the street environment by reducing the number of HGV’s travelling through the air quality management area in the centre of Witney.
Financial and Staff Implications
17. As this project relies on developer contributions there are a number of implications that need to be considered. Please see the section above entitled ‘Cost implications’ (bullet points 8-9).
RECOMMENDATION
The Cabinet Member for Transport is RECOMMENDED to:
(a) approve the principle of an at-grade roundabout at the A40/Downs Road junction;
(b) authorise officers to progress the scheme to the detailed design stage and to submit a planning application for the scheme, subject to the provision of a satisfactory Environmental Impact Assessment.
Steve Howell Head of Transport Environment & Economy
Background papers: Nil
Contact Officer: Cathy Browning, Tel 01865 810415
April 2008
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