The scope of the TA is determined by the over-riding need to demonstrate how the transport demands of a particular development can be met within the base and future transport network. This should take into account infrastructure, transport services, transport capacity constraints and how the impact of the development can be mitigated. 

In addition to the above, a key consideration is to assess the conformity of proposals with policy. Therefore the TA should set out how the development complies with relevant transport policies. The London Plan, the Mayor's Spatial Development Strategy published in 2011, is the key policy document that referred planning applications are assessed against by TfL, alongside the Mayor's Transport Strategy. Depending on the site, there may also be site-specific planning policy documents such as Supplementary Planning Documents which need to be taken in account alongside London Plan and Local Plan (formerly Local Development Framework) policies.

There are a number of other relevant policy and guidance documents that should be taken into account.

Traffic Management Act

Of particular note is the Traffic Management Act (TMA) 2004. The TMA places a Network Management Duty on local traffic authorities, including TfL, with objective to secure the expeditious movement of traffic, including pedestrians. Therefore TfL has the role of proactively safeguarding the operation of the TLRN and SRN. The TMA requires that all London boroughs must notify TfL if they are proposing to "exercise any power under the Highways Act or Road Traffic Regulation Act in a way which will affect, or be likely to affect a GLA strategic road."

Planning permission does not discharge the requirements under the Traffic Management Act 2004. Separate formal notifications and approval are needed for both the permanent highway schemes and any temporary highway works required during the construction phase of the development. Therefore, while the TMA process is separate from applying for planning permission, it is critical that there is alignment between the statutory planning process and statutory highway approval process.

It is essential for applicants to consider the implications of TfL's Network Management Duty in transport assessments and discuss this with TfL Borough Planning as early as possible. This is to ensure that the highway assessment, modelling and mitigation that is approved at planning stage is capable of approval at TMA stage.