A walking audit is an assessment of the walkability or pedestrian access of an external environment. Walking audits are often undertaken in street environments to consider and promote the needs of pedestrians as a form of transport. They can be undertaken by a range of different stakeholders including: A walking audit is an assessment of the walkability or pedestrian access of an external environment. Walking audits are often undertaken in street environments to consider and promote the needs of pedestrians as a form of transport. They can be undertaken by a range of different stakeholders including: Walking audits often collect both quantitative and qualitative data on the walking environment. The Pedestrian Environment Review System (PERS) is the most developed and widely used walking audit tool available.PERS is “a systematic process to assess the pedestrian environment within a framework that promotes objectivity”. The environment is reviewed from the end user perspective of a vulnerable pedestrian. PERS consists of: A PERS walking audit collects both quantitative and qualitative data on six types of facility in the street environment: Each facility is rated on a seven-point scale (-3 to +3) for different parameters such as effective width, dropped kerbs, permeability, or personal security. PERS also rates disabled peoples access. These PERS ratings are linked to Red/Amber/Green (RAG) colour-coding. The PERS software allows users to analyse and display walkability data using GIS maps, charts and quick win recommendation lists. PERS was originally developed in 2001 by TRL and London Borough of Bromley. The software tool (PERS 1) was designed to allow transport professionals and community groups to quickly and cost-effectively assess and rate the walkability of local streets and recommend improvements for pedestrians. This version of the tool assessed Links, Crossings, and Routes. In 2005 Transport for London and TRL co-developed PERS 2 which expanded the original system to include Public Transport Waiting Areas (PTWA), Public Spaces and Interchange Spaces. In 2009 transport for London and TRL further developed the tool into PERS 3 which included a built-in GIS mapping tool and the ability to add photographs and georeferences of quick wins (low cost, easy to implement physical improvements). PERS 3 also has the added functionality of automatically generate quick-win recommendation work lists for Highway work crews. The PERS tool has been used by organisations all over the world and has been used extensively in London to assess over 200 km of the street network. Research undertaken by the Commission for Architecture and the Built Environment (CABE) have used the PERS walking audit method to show:'how we can calculate the extra financial value that good street design contributes, over average or poor design'. The study found a direct link between an increase in PERS scores (and therefore an increase in the quality of a street for pedestrians) and residential house prices. The study demonstrates how PERS can be used to show how:'clear financial benefits can be calculated from investing in better quality street design'.