Common WCAG 2.1 AA Pitfalls in Engineering PDFs

The PDF Problem

Engineering PDFs are the single most common point of failure in municipal contractor accessibility audits. Site plans, CAD exports, structural drawings, and specification documents are routinely published without any accessibility metadata.

Under the new DOJ Title II rule, every PDF you submit as part of a public project must be accessible to assistive technology users.

Top 3 Failure Points

1. Missing Alternative Text on Diagrams

Standard OCR cannot interpret engineering schematics. A site plan showing grading contours, utility runs, and ADA-compliant pathways requires human-quality descriptive text that explains what the drawing communicates — not just what shapes are present.

AI-powered tools can now generate draft alt-text for complex engineering imagery, dramatically reducing the manual effort required.

2. Broken Reading Order

When PDFs are exported from CAD or design software, the logical reading order is often scrambled. Screen readers will jump between text blocks in an unpredictable sequence, making the document incomprehensible.

Fix this by tagging the PDF structure and setting an explicit reading order that follows the document's visual flow.

3. Untagged Tables and Data

Specification tables, material schedules, and cost breakdowns must have proper table headers and data cell associations. Without these tags, a screen reader presents the data as a flat stream of text with no structure.

Building Your Defense

Document every remediation step you take. A timestamped audit log showing your "good faith effort" to make documents accessible is your strongest defense against both municipal auditors and plaintiff attorneys.