Employees or students late for work or school because of delays in New York City’s public transportation system can get notes from the transit agency to give to their bosses. Anyone can request a delay verification letter over the phone, and an official note will arrive in the mail within two weeks.

NYC Transit says it mails more than 34,000 a year.

One catch: The letters verify the exact time and length of the delay, not just the date. So if you’re going to stretch that 10-minute power outage into a half-hour coffee break, you’ll need some other evidence to back up your story.

Phone and “snail mail” not your preferred method of getting a letter? Don’t fret — NYC Transit is working on an online system that can accept Internet requests and automatically e-mail your boss the excuse letters.