Traffic

The Council state:

‘During the busiest periods it (Sainsburys Horfield) is likely to lead to queues in both directions along the full length of Filton Avenue between Gloucester Road and Muller Road’. And without mitigation ‘it could lead to additional queuing on the A38 Gloucester Road. At the busiest times this could extend potentially several hundred metres in both directions. The increased likelihood of traffic using alternative routes, delays to bus journeys and potential delays to emergency services with extended queuing in both directions’.

• Junctions in the area will be pushed to 143% of their rated capacity with this development. (Govt. guidelines for junction capacity in urban area give a design limit of 85%). (DMRB Vol.6 pt.2 sec.6)

Development Control North Committee recently objected to a housing development PT12/1930/O on the basis of junctions being pushed to 95% capacity stating ‘Given that the normal maximum design RFC is 85% this is not considered acceptable’
Paragraph 4.17 DEVELOPMENT CONTROL (NORTH) COMMITTEE 15 January 2014
ITEM NO.1

• The development could not be effectively modeled as their software does not work well with this level of conjestion.

• Pavements are to be thinned to create extra queuing capacity both sides of Churchways Avenue.

‘there will be prolonged ‘peak’ effects’ – this means traffic jams that start well before rush hour and end long after rush hour.

It cannot be convincingly asserted that this is not the description of a severe traffic impact. It would be a dereliction of duty to the public and residents on these streets to dismiss such an impact that makes them unable to leave or return to their homes due to traffic gridlock for significant periods of every working day.

Planning policy M1 states: development should: (iii) avoid the introduction of traffic of excessive volume, size or weight on to unsuitable highways or into residential and other environmentally sensitive areas.

However, in his summary the Council’s officer manages to state that in his consideration of this development ‘There is insufficient evidence to conclude that there would be a severe impact on the surrounding road network’.

TRASHorfield believe this conclusion is irreconcilable with the evidence that the Transport Development Management Team submit.

So what is the Council’s argument to justify this conclusion?

The Council’s officer writes ‘’It is noted that this impact may be offset by the following driver behaviour characteristics’. But that ‘It is not possible to quantify these, although the applicant has suggested a 10% reduction in vehicles to account for a wider strategic alternative route choice’.

It must surely be recognised that if it is the duty of an officer to avoid a severe impact through development control  and a proposal is predicted to create a severe impact, then a dutiful officer would not accept some unquantifiable and untested ‘hunch’ as argument that the severity will be 10% less severe. The acceptance of the stated ‘unquantifiable’ mitigation is inexplicable – why model the traffic at all?

Various driver behaviours are then suggested that may reduce the severity; such as rat-running, change in journey time, or not making the journey at all.

But it is predictable congestion that causes drivers to change their behaviour. The case officer therefore accepts that this development cannot be accommodated with available highways and junction management techniques without traffic jams of such regularity and scale that drivers routinely take other roads around this section of Filton Avenue. The case officer is therefore admitting that the only option they have is to allow the traffic system find a new equilibrium. This response is not acceptable when the option to refuse the proposal is available and policy guides the officer to prevent the cause of the traffic increase by recommendation for refusal. Instead the officer relies on anti-social and dangerous driving behaviours that convert presently calm residential streets into rat-runs.
This ‘driver behaviour’ argument displays a reckless disregard for the concept of ‘highways planning’ and the interests of residents along these roads. It allows arterial roads to be removed from civic purpose due to the interests of a private company. This argument uses the phenomena of ‘rat-running’ as transport policy. One diversionary route is Downend Road, past two schools (Ashley Down Primary School Board of Governors have objected to this application.) Another is the already narrow and dangerous Churchways Avenue. The full effects of displaced traffic have not been modeled due to limited data and cost, as acknowledged by BCC.

It should be realised by the officer that if it is the severity of the traffic that limits the congestion then as one effect serves to reduce the traffic the argument simultaneously fills the capacity it has created. The officer should account for the circularity of this argument and simply state the traffic will be so severe that only its severity limits how severe it is – or simply state that the demand for road space with this development significantly outstrips supply and therefore the impact will be severe and the development should not be permitted.

With a 572 space car park, Sainsbury’s know that people will NOT walk. On Saturday 12 January, a survey was carried out at the much smaller Golden Hill Tescos: 85% of visits were by car. The applicants claim 75% of journeys will be made by car, this is highly unrealistic.

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