The LATIS modelling to date focuses largely on strategic patterns. However, through a sub-area analysis process it can also be used to represent local issues. The road network and travel patterns associated with the relevant geographical area can be extracted, creating a new smaller model known as a ‘sub-area model’.

A sub area model can then be supplemented by additional data, a disaggregation of the zoning system (ie increasing the number of zones to make the model more detailed) and a more detailed representation of the network (ie the adding of more local roads and modelled junctions).

The most notable examples of sub-area models created using TMfS are the Forth Regional Model (FRM), the Aberdeen Sub Area Model (ASAM) and the Dalkeith Sub-Area Model (DALSAM). All models were designed to appraise specific schemes (the Forth crossing, the Aberdeen Western Peripheral Route and the A68 Dalkeith Northern Bypass) and were subject to a number of enhancements to zones, data and networks to provide a more detailed representation of local travel patterns.

Such a model could be created to assess local schemes and has the potential to be highly valuable to model users.

Sub-areas can be extracted for the base-year and forecast year scenarios.

The travel demand associated with a sub-area can also be extracted from the LATIS models and input to other local models, such as microsimulation models. This process can provide an efficient mechanism to identify how travel patterns may change within a local area from the introduction of transport interventions located out with the local model coverage area.