Privacy

Who runs the site

Pavement Interactive is published by HeadLight. Questions about this page, or a request to see or delete anything we hold about you, go to privacy@headlight.com.

When you read

We count visits with Fathom Analytics, which uses no cookies and keeps no personal data: we see which pages are read and roughly from which countries, never who read them. Our hosting keeps routine server logs, including IP addresses, for security and fault-finding, and does not use them to identify readers.

The site remembers two display choices in your own browser, never on our servers: whether the chapter list is open or minimized, and the All, Asphalt or Concrete switch on chapter pages. When you choose to print or save a calculation, the calculator also keeps what you typed in your browser for that visit, so it isn’t lost while you sign in. Clearing your browser’s site data forgets them.

Your free account for calculations

The calculators, their results and their working are free to use without an account. A free HeadLight account adds the printable calculation form, saved calculations and article alerts.

• Signing in. You sign in with a 6-digit code we email to you; there is no password. We keep your email address, and the name, organization and role you give the first time. Your name and organization print on your forms. While you are signed in, the site sets two cookies: one for the account pages, and one that holds nothing about you and only lets the site’s header say My calculations instead of Sign in.
• Saved calculations. When you save a calculation we keep the calculator and its version, the values you typed, the result we calculate from them, any specification limit you entered, the project details you type on its form (project, sample ID, source, date tested and technician) and the page you saved it from. Your last project, source and technician start your next form. Only you can open them. You can export them as a spreadsheet file.
• Article alerts. Saving a calculation from an article signs you up for alerts on that article: when the article is corrected after technical review, we send you one short email with what changed. You can turn alerts off, or remove one article, in your account.
• New calculators and articles. Only if you tick the box, which is unticked to start with: an email when new calculators and articles go up, about four times a year, and one click in any of them stops them. We keep your choice, the date you made it and the exact words of the box you ticked, and you can change it in your account at any time.
• Deleting. “Delete my account and data” in your account deletes your account, saved calculations, alerts and sign-ins at once. Forms you printed are yours.

We send these emails through our email service. We don’t sell your details or share them for anyone else’s marketing.

Videos

Videos are hosted on YouTube. Nothing loads from YouTube until you press play; then the video plays in YouTube’s privacy-enhanced mode, under Google’s privacy policy. “Watch on YouTube” takes you to YouTube itself.

When you write to us

• Report an error. We keep what you write and the article it is about. Your email is optional and used only to reply to you; it is deleted when the editors close the report.
• Register a course. We keep the course, the institution and your email to confirm the listing. Your program appears on the site only if you tick the box that allows it.
• Questions to engineering firms. A question sent from a firm’s listing in Find an engineer goes to that firm, which answers you directly.

We don’t sell or share what you send for marketing, and writing to us doesn’t add you to any mailing list.

Find an engineer

The directory lists firms, not people, from public state records: the state engineering board’s firm registrations and state transportation departments’ prequalified consultant lists. It shows a firm’s name, city and what it is licensed or prequalified for. A firm can ask to correct or remove its listing.

Editors and reviewers

Staff and invited reviewers sign in to the editor with Google. For them we keep their name, email, role and affiliation, and for reviewers their license number and when it was checked. The editor sets one sign-in cookie, needed to stay signed in. A reviewer’s name, affiliation and review date appear on the articles they review.

Where it is kept

The site and its data are hosted in the United States (Fly.io, with files in Tigris storage). Backups are encrypted and kept for up to twelve months, so a deleted account leaves the backups as they age out.

Changes to this page

If this changes, the new version is posted here with its date. Last updated October 31, 2026.