West Way Community Concern – Annex to Comments on the Additional Documentation (2014-09-08) for Planning Application P13/V2733/FUL Traffic and transport Impacts – September 2014 amendments Top Line Flaws in the Transport Assessment (TA) submitted with the December 2013 Planning Application as a result of questions raised by Oxfordshire County Council (The Local Transport Authority) and the Highways Agency led to some fundamental changes being made to the design of the TA. But both Transport Assessments that have been produced for the proposed development are fundamentally flawed. Both underestimate the amount of traffic that will be associated with the development on local roads. Both produce very similar results, which happen to show levels of traffic that will not cause problems, but which show enough patronage to make the proposed centre viable. The amount of traffic that is forecast from the very local area is totally implausible (which has the effect of making traffic coming from a distance seem less). Given these two flawed Transport Assessments it is not credible that a sound assessment could be made which would show the development to not create traffic problems. Introduction Two Transport Assessments have now been undertaken using different methodologies, with the second claiming to address issues in the first. They both come to remarkably similar conclusions, but both have many flaws. This appears to point to a deliberate attempt to use complex models to confuse readers, and manipulating assumptions in order to produce results that show the proposal to be viable but not producing excessive traffic. Both have shown a serious lack of local knowledge, with the second merely addressing the most prominent issues raised by the County Council Highways Department and Highways Agency. That the two assessments are both implausible is further evidence that this proposal cannot work without large increases in traffic. Annex 1 contains a short guide to the traffic forecasting elements of a Transport Assessment. Further Annexes, each with a short summary, provide further explanation of the points made below. Comparison of the two West Way assessments This section compares the TA provided with the initial application with that provided in the September 2014 amendment. A sentence describes an aspect of the initial one, while the bullet point shows how it has been altered. (The initial TA) Used different estimates of traffic generated by the development to suit its arguments; • The new version uses only the lower set of data which is for mixed weekdays. Using Fridays (which is what TAs generally assess as a weekday gives figures about 15% higher); (see Annex 2 – Trip Generation) 1 Assumed people would travel from areas that suited its traffic forecasts rather than where patronage would be most likely to be generated from. • The methodology has been altered in response to criticism, but 36-41% of VEHICLE trips are now forecast from a zone of 2803 people who live within about 500m of the site – many times more than is plausible; (See “Annex 3 – The Gravity Model”) Failed to recognise the existence of Westminster Way as the preferred route from the A34 to Botley. • Some account has been taken but it underestimates the amount, partly due to the above, and partly due to ignoring that satnavs send people along Westminster Way and that non local people will soon learn of the shortcut (see Annex 4 – Routes used to reach the site) Assumed that people will use routes that are not credible (e.g. driving through central Oxford from Cowley and Headington). • These have been adapted but still make implausible assumptions, such as the percentage of Cumnor traffic using Cumnor Hill and the A420 to reach the site; The Cowley issue still remains but is less important since so few are now forecast to come from Cowley – seemingly designed to reduce the proportion using the ring road and Botley Road. (see Annex 4 – Routes used to reach the site) Made assumptions about people using the centre who are already ‘passing by’ that are too high given local geography, while assuming that all trips to the current centre are all specially made to go there. • These have been altered, but are just as unlikely – the same proportion of people passing by who will stop is used as for Waitrose on Botley Road, even though much more patronage there is likely to be from passing trade, due to the congested nature of the Botley Road; again, only supermarket funded research from dissimilar locations is quoted. (See Annex 5 – “Diverted and Pass-By traffic) Failed to look beyond very local junctions in terms of traffic diverting (missing out the possibility of traffic diverting from the A34). • This is still true, and ignores the possibility that traffic will come on along Westminster Way, before heading North again; (See Annex 5 – “Diverted and Pass-By traffic) Assumed that people will link their shopping trips to such an exaggerated extent that the total trips to all shops turns out as less than those to the supermarket on its own. • Minor changes have been made but the total trips to the entire centre is still quite often less than that expected for the supermarket alone; They quote supermarket funded research from areas that are not like Botley, while ignoring other research. (See Annex 6 – “Secondary Linked Trips”) Used a survey to show how much traffic uses the current centre, but ignored the possibility that people drive straight through without stopping, and stop to drop children off for school but do not use the centre. • Not changed, but a recent survey by West Way Community Concern shows at least 19% of traffic in the morning peak is not using the centre. (see separate report “Errors in June 2013 traffic survey 25-09-2014”) 2 Made assumptions about how many trips should be added to the current situation due to unused office space, that are exaggerated. • Not changed; (These two points mean that traffic using the current site is overestimated, which has the effect of making the proposed development look as though it is adding less traffic than it actually will do). (see initial objection) Showed parking levels to be close to, but below, capacity. • This has been completely changed using lower trip generation rates, and assumptions that include those working at the site (amounting to 97 vehicles throughout the day) will park off- site – presumably in the surrounding streets; (see Annex 7 – Parking) Was optimistic about parking levels off site saying there would not be a problem, but with no evidence put forward. • Now uses a large area to assess ‘parking stress’ and concludes that 390 vehicles would need to be parked within 400m to cause 90% parking stress. The 97 expected employees cars (at any one time) and other parking could mean stress could be reached in the 200m radius normally use very much sooner; (see Annex 7 – Parking) . The real effect would be likely to be to large increases on most roads in the area, but with especially large increases on Westminster Way from the A34, and much greater congestion on the already congested West Way, Botley Road and A420 link from Botley Road to the A34. Westminster Way is in an Air Quality Management Area and that the extra traffic and likely congestion would add to emissions and pollution levels there. 3 Annex 1 - A Layperson’s Guide to Transport Assessment traffic calculations There is an entire industry devoted to writing Transport Assessments (TAs). They are commissioned by developers who want to see their development built. In order to gain planning permission they need to show that the traffic impacts will not be ‘severe’, so developers won’t want to pay for a TA that doesn’t back up their case. ‘Severe’ impacts usually occur where noticeable congestion will happen, and that assessment of congestion (or delays at junctions) is the very last stage of the analysis. So if congestion is predicted consultants will sometimes go back in the process to alter the figures until the ‘correct’ result is produced. Hence, in a sense, the tail often wags the dog. For the traffic prediction part of a TA, consultants will usually initially conduct what they feel is a fair assessment of how much traffic will be produced by the development, where it will come from and how it will be distributed across local roads, and then work out what that means for congestion at junctions. It is a multi stage process, for which there is no standard procedure. For most smaller developments it will be found that there will be few problems caused, but if there is any doubt, or if congestion is shown to the likely, the consultants have plenty of scope to play around with the figures and assumptions to make it look as though there will be no problem. It has been said that transport assessment has the complexity of rocket science but the accuracy of a circus cannon. There is plenty of jargon which is not always used in the same way, and even most transport professionals baulk at the thought of unpicking the details of how a TA has been done and whether it is correct or fair. The inherent inaccuracy of prediction coupled with the knowledge that most people (including Local Authority staff and Planning Committee members) will not feel able to challenge what is written, ensures that consultants have got used to getting away with showing that some major developments will have little traffic impact. In many cases they’re right – traffic to some developments will be largely due to people who are passing by anyway – a petrol station is an obvious example! Most new developments do not generate entirely new journeys but change the day to day travel patterns that people are making already.