2 Study methodology
The starting point for this study is the well-established understanding of the potential community impacts of road traffic. These have been evaluated and managed for many years, leading to the development of established policy and guidance for dealing with road traffic impacts in Scotland.
In order to evaluate the potential impacts of traffic associated with unconventional oil and gas development in Scotland, we have firstly set out the policy and regulatory controls on road traffic associated with new development in general, and UOG in particular. We have then investigated the likely scale of material quantities and traffic changes associated with UOG activities in Scotland. This was carried out on a site-specific basis, and then combined with scenarios for shale gas development in Scotland developed as part of the assessment of economic impacts.  We have considered these impacts in the context of traffic statistics for Scotland, and typical traffic impacts of comparable developments.
We have considered evidence for the community impacts associated with road transportation in general, and with UOG-related traffic in particular, and assessed the extent to which the community impacts resulting from transportation due to UOG development can be avoided or mitigated.
Based on this analysis, we have drawn conclusions regarding the potential impacts and made recommendations for measures which would be needed to mitigate impacts, and areas where further research would be useful.
2.2 Material movements by process stage
The principal activities giving rise to transportation requirements (including movement of personnel) can be summarised as follows: 
1. Well pad and road construction equipment/materials
2. Drilling rig
3. Drilling fluid and materials
4. Drilling equipment (casing, drill pipe, etc.)
5. Completion rig
6. Completion fluid and materials
7. Completion equipment (pipe, wellhead)
8. Hydraulic fracture equipment (pump trucks, tanks)
9. Hydraulic fracture water
10. Hydraulic fracture sand
11. Removal of waste water and other waste materials
In order to evaluate material movements associated with UOG development, we have used reports produced by New York State,  the Tyndall Centre  and the Institute of Directors  as a starting point. These evaluations were also highlighted by consultees as key references. We have undertaken a literature review to identify any changes which may have occurred over the period since these studies and our own analyses , were conducted. Information on material volumes is closely linked to information on traffic flows associated with the quantities of material moved. For example, the Tyndall Centre report provides an analysis of expected flowback fluid and produced water quantities. This is used to develop the estimates of flowback water removal shown in Table 2.
These key references are focused mainly on shale gas developments. We have also reviewed and analysed the activities associated with coal bed methane to characterise the sources of truck movements. In this case, the water requirement for hydraulic fracturing is likely to be significantly lower, but the requirement for treatment and potentially removal of potentially contaminated produced water can be expected to extend throughout the lifetime of the well. We have researched the published literature in relation to coal bed methane development and also consider environmental statements and Transport Assessment reports submitted in support of planning applications for coal bed methane development in Scotland.
If UOG development goes ahead, there would be variability in the plant, equipment and materials which are required to be transported to/from individual sites, and the resultant traffic movements. This variability would be related to the size and nature of a well pad site ( e.g. existence of sloping terrain; previous use; number of wells), and to the extent of drilling and fracturing to be carried out. The quantity of flowback fluid and produced water would be variable and cannot be predicted with confidence. Consequently, the approach adopted in this study has been to identify a likely range of material quantities and traffic movements, based on limited experience of UOG development in Scotland and England, and more extensive experience in the USA.
The outcome of this approach was a schedule of activities associated with UOG development, covering both shale gas and coal bed methane. Each activity would have an estimated range of potential activity. The timing of each activity in the process development has been highlighted and a visual representation of this timeline developed. Each activity has been presented on the basis of "per well" or "per well pad" as appropriate, and we have also provided an indicative range for development of UOG resources in Scotland as a whole.
2.3 Likely scale of traffic changes
The likely scale of traffic changes needs to be understood for the four stages of unconventional oil and gas development: (1) exploration, (2) appraisal, (3) production and (4) decommissioning / restoration.
The scale of the impacts for an individual development can be broken down into the following characteristics which must be considered for each stage of the development:
- Total traffic volumes for each stage and broken down into activity or material to be transported (plant, aggregates, hazardous materials, construction materials, extracted products etc)
- Total HGV volumes for each stage
- Traffic (total and HGV) volumes broken down into monthly, weekly and daily movements
- Details on the types of vehicle that would be used for each task (weight, length, width etc) including details of any abnormal loads
- The typical programme for each stage of the development
The information that we have reviewed includes:
- Analyses of the road traffic impacts of UOG development including the Ricardo evaluations for the European Commission and CCAN; , the Tyndall Centre report;  the Institute of Directors report;  the Independent Expert Scientific Panel report on Unconventional Oil and Gas  .
- Any more recently published evidence on transportation impacts of UOG development.
In addition to the above, we have reviewed how traffic volumes and impacts might vary depending on location. We have reviewed case study information and published research in order to characterise the potential differences in traffic impacts depending on location.
From the information gathered, the parameters that contribute to determining the traffic impacts of Unconventional Oil and Gas developments were summarised. We have commented upon the likelihood of any strategic or local impacts, and how any such impacts would be managed, taking account of the standard of the road network and the setting of the development.
2.4 Case studies
A number of case studies were evaluated to provide information on a range of potentially relevant development types:
- Review of the traffic impact during exploratory drilling and hydraulic fracturing, Preese Hall, Weeton, Lancashire;
- Review of EIA and planning appeal information for Roseacre Wood, Lancashire;
- Review of air quality impacts of traffic resulting from proposed Roseacre Wood development;
- Review of EIA undertaken in relation to the coalbed methane site at Letham Moss Falkirk;
- Review of EIA work undertaken for Earlseat windfarm in Scotland;
- Review of EIA work undertaken for Rusha Surface Mine in West Lothian;
- Review of EIA work undertaken for Tomfyne Quarry in North Lanarkshire;
- Review of transportation impacts associated with UOG development at rural sites in Western North Dakota;  and
- Review of transportation impacts associated with UOG development at urban sites in Tarrant and Johnson Counties, Fort Worth, Texas. 
The case studies are set out in Appendix 1.