Transport for London – TEXT LEGIBILITY STANDARD 2023

Description

This TfL Text Legibility Standard (Issue 3) sets rules to ensure clear, accessible typography across all printed and digital TfL outputs. The corporate typeface is Johnston 100 (Headings: Medium; Body: Light at 12pt or below, Regular above 12pt). Minimum point sizes are determined by expected viewing distance and are mandatory for standard poster and leaflet formats. Informed by RNIB guidance, the typographic policy requires mixed case, left-aligned (ragged right) text, restricted centring for short poster copy, no justification, no vertical/angled text, no italics, no tracking, and no first-line indents; emphasis should use weight changes. Line length must not exceed 70 characters; creative typefaces are only allowed for campaign headlines (not body or calls to action). Contrast must meet WCAG AA: 4.5:1 for normal text (<18pt) and 3:1 for large text (≥18pt); TfL recommends tools like WebAIM’s Contrast Checker and reserves final approval with the Graphics team. For sizes not listed or queries, contact corporatedesign@tfl.gov.uk.