RE: BABA27 Concepts. I am a retired chartered civil engineer and transport planner who prior to retirement worked for WSCC Highways.
I was the lead officer representing WSCC in partnership with the then Highways Agency on the early development of improvements for the A27 Chichester bypass in conjunction with an integrated transport plan for Chichester. I was also involved in the early development of the Chichester and area transport model.
In retirement I live in Parklands Estate and I am a highways technical adviser to Parkland Resident Association. As such I attended all the BABA27 forums.
Living in Parklands I have no NIMBY bias towards any of the two ‘concepts’ now being considered. My following subjective views on these are based on 40 years’ experience designing and building numerous major road schemes.
The mitigated north concept gives:
The best long term solution
The best opportunity for a longer term integration of future land use planning and future major transport improvements (i.e. joined up land use /transport planning).
With a junction on the A286 (whatever design) it will;
Intercept longer distance N-S traffic who still wish to access the A27 (east or west)
Attract local traffic from the north side of Chichester who also wish to travel east or west along the A27.
Enable redirection of many HGVs away from the local city roads to access the existing A27 or the industrial estates next to the existing bypass.
Significantly reduce through-traffic on local roads (e.g. Orchard Street/other sections of the ring road and rat-running traffic through Parklands.
By reducing traffic on local roads it will:
Free up road space and enable the development of more sustainable transport such as walking, cycling and public transport.
Enable meaningful traffic management measures to be implemented.
A northern concept could also:
Enable a new direct private road connection to the Goodwood Estate for use on major event days. This would reduce the traffic impact of such events on the local city roads.
The environmental impact of the northern concept can be substantially mitigated by modern highway design techniques. A target of a net environmental gain is possible.
There will be minimum disruption of public utility apparatus and every opportunity for laying new apparatus for future needs.
The on-line full south concept
In comparison this will:
Have a limited life span before it is once more at full capacity;
Take much longer to construct;
Have unacceptable traffic delays during construction resulting in much rat-running through the local city roads;
Have limited opportunity for long term integration of future major development (integrated land use/transport);
Not fully separate local and through traffic (many local trips use sections of the bypass to get from one junction to another);
Incur significant disruption of public utility apparatus, the cost of which will be very high and likely to be underestimated;
With underpasses, incur significant ground water problems during and after construction as it is in the flood plain;
Have an unacceptable impact on the Chichester Canal if an underpass at the Stockbridge junction is built. A lowering of the canal using locks will result in a severe restriction of recreational activities emanating from the basin. It will also result in significant loss of valuable water from the basin;
Have a significant adverse environmental impact on local residents during and after construction.
I hope that any final ‘concept’ preference by WSCC and CDC will be based on a long term vision for Chichester. I also hope that Highways England make a final decision based on the wider Chichester perspective and not just on improving east/west movement on the A27 trunk road.