Our ref.: 1466/90/MC/jmc

Date: 21 September 2007

Moira Gibb
Chief Executive
London Borough of Camden

Dear Ms Gibb

Little Green Street – Construction Access Method Statement

We have been retained by the residents of Little Green Street to advise them in
relation to the Constructional Methodology Statement (CMS) for the development of the former British Railway Staff Club site, which was prepared by PTP Architects in relation to Appeal Decision APP/X5210/A/02/1097183 and submitted to you last month.

We have consistently advised throughout that the use of Little Green Street as a construction access must be assessed not just in narrow highways engineering terms but in light of much wider issues that are to do with the scale and character of the street and its importance as part of the conservation area. It must be recognised that the street is in reality a shared surface that is used frequently by many people. Their safety and particularly the safe access for residents to their homes will be compromised by the proposal to use Little Green Street as a construction access.  National guidance classifies the street as being able to accommodate only occasional private cars.

We have reviewed the Constructional Methodology Statement and advise that it doesn't address traffic and highways issues in the following respects:

1. Predicted Construction Traffic
The programme for proposed works is based on the number of predicted vehicle trips set out in Appendix 11.  However, when the report refers to ‘number of trips’, it does not make it clear whether it means a one or two-way journey to the site. Table 5 predicts an average vehicle flow of 4 per hour over a six-hour period, five days a week for the duration of the demolition, excavation and concrete phase of the works. This is incorrect and is nearly double this figure.

The figures in Table 5 have been based on the number of vehicle loads required to dispose of the excavation and demolition material, however one vehicle load will usually generate two trips (in and out) on Little Green Street. This is confirmed by the revised traffic calculation included in the Pavement Evaluation Report (Appendix 2), which calculates the maximum number of vehicle trips on Little Green Street to be 13610 for the demolition, excavation and concrete phase. This equates to 7 trips per hour (40 per day) on Little Green Street for the 68-week programme.

The 68-week programme was derived from the assumption of 20 trips per day or 100 trips per week. This was applied to the number of trips quoted in the schedules in Appendix 11, (i.e. 6805 trips ÷ 100 trips/week = 68 weeks).

This is not correct, since the actual number of trips (13610) is nearly double this, as explained above. Therefore, either the construction programme should be doubled, or the impact on Little Green Street is double the number of trips that the CMS makes out.

Although the CMS states that Banksmen will control Little Green Street, the higher frequency of construction vehicles means that vehicles entering and exiting will frequently try to access Little Green Street at the same time; there is no facility for vehicles to wait on Highgate Road or reverse back into the queuing lane so they will have to reverse on Little Green Street, which is unacceptable.

 
2. Vehicle Tracking
The only vehicle tracking included in the CMS is for a 6.5t vehicle entering Little Green St from Highgate Road. Vehicle tracking must be undertaken for all of the proposed construction vehicles entering and leaving the site from Highgate Road. The concrete batching plant is of particular concern since this would have to be delivered directly onto the site on the back of a lorry that is very significantly larger than the 6.5t vehicle.

The left-turn out of Little Green Street onto Highgate Road is the most constrained manoeuvre and construction vehicles are likely to swing out into the oncoming traffic, which raises safety concerns particularly when considered with the traffic management system that is proposed.  The problem applies to the frequent vehicles, not just the exceptional vehicles proposed.  On this basis alone, the proposal is unacceptable.

3. Temporary Traffic Management Scheme for Highgate Road
The temporary lane widths of 3.4m on Highgate Road (shown on drawing CS-025562/001A, Appendix 3 of the CMS) cannot be achieved. Highgate Road is at most 10.0m wide, reducing to 9.4m locally in places. According to chapter 8 of the traffic signs manual (Traffic Safety Measures and Signs for Road Works and Temporary Situations Part 1: Design, 2006), the desirable minimum lane width is 3.25m therefore where there are three lanes and two water-filled barriers (0.5m wide), the desirable minimum width required is 10.75m, which cannot be achieved.

An absolute minimum lane width of 3.0m is quoted in the guidance, however this is not appropriate where the road is used regularly by large lorries, buses and cyclists and particularly where there are turning vehicles as is the case here.  The narrow lanes will result in disturbance to, and displacement of the barriers by large vehicles and the likelihood is that Highgate Road will become chaotic as a result.

The strategy is for ‘low loaders’ to stop and off-load on Highgate Road. The CMS does not include any vehicle tracking drawings to demonstrate that there is sufficient space for the vehicles to off-load and access Little Green Street without conflicting with the running lanes on Highgate Road.  We have looked at this and consider that there is a major problem with this proposal.

The wider issues alone make Little Green Street unsuitable for the construction access. In addition, if the programme is to be maintained, the volume and frequency of construction traffic on Little Green Street is actually double that quoted in the CMS, which exacerbates safety issues for the residents and pedestrians that currently use the street.  These have not been addressed in the CMS. Therefore we do not believe that it is appropriate to use Little Green Street as the construction access for the scale of development proposed.

We cannot see how an acceptable, safe and workable solution can be achieved. We believe that the problems associated with construction access to the site in effect mean that it is not possible to construct the development that has planning permission.  Some other access route needs to be found or else a completely different proposal needs to be considered for the site.

Yours sincerely


Michael Coombs
Senior Partner

Alan Baxter & Associates LLP

75 Cowcross Street
London
EC1M 6EL

Tel 020 7250 1555
Fax 020 7250 3022