What is a 15-Minute City? Walkability Scores Explained for UK Architecture Sites

Define the purposes of the assessment: access to food shopping, education, health care, public transport, work, green space or other services relevant to the brief. Record opening hours, eligibility and capacity where these affect practical access. A school entrance nearby does not prove a place is available.

Consider different users and journey conditions. A single assumed walking speed will not represent every age, mobility need, gradient or weather condition. Explain the assumptions rather than presenting a catchment edge as an exact universal travel time.

Transport for London’s WebCAT guidance explains that PTAL combines walk time to the transport network and service wait times. It is useful evidence about access to public transport in London. It does not directly measure all amenities, pedestrian quality, step-free journeys or spare transport capacity.

Do not describe an Atlasly composite access score as an official TfL PTAL unless the source and method establish that equivalence. Outside London, identify the authority’s relevant method and actual service evidence rather than inventing a nationwide equivalent PTAL.

The London Plan 2021, policies D2 and D3, links development capacity to context, design and supporting infrastructure. The previous article incorrectly presented an old PTAL density matrix as a current 2021 rule and included unsupported dwelling-per-hectare bands. That table has been removed.

PTAL can inform the assessment, but it does not automatically grant a density, height or parking outcome. Test design options against the adopted plan, local policies, access to services and infrastructure capacity. Record the applicable policy and the actual supporting evidence.

Check entrances, crossings, paths, gradients, barriers and any access restrictions on the important routes. Compare the mapped route with a site visit and current local information. Mark assumed links and missing data.

Record the routing network, calculation date, speed assumptions and destination source. An isochrone generated from incomplete paths can give a precise-looking but misleading result. Present route improvements as proposals requiring feasibility and delivery checks, not as benefits already secured.

Compare entrance positions, pedestrian connections, crossing needs, cycle provision and servicing conflicts. Prioritise inclusive routes and legible public space. A shared surface is not automatically an accessibility improvement; assess the needs of disabled users and the applicable design guidance.

Use Atlasly walkability context as an early evidence aid where available, and retain the limitations with the output. The useful conclusion explains the destinations and journeys supported by the evidence, what remains uncertain and which interventions would need agreement and delivery.