CHICAGO, Feb. 20, 2014 /PRNewswire/ --From escaped zebras to must-see TV, employers share some of the most unique excuses they've heard from tardy employees in a new CareerBuilder study. The study also finds that nearly one quarter (23 percent) of employees admit to being tardy at least once a month on average, with 15 percent admitting to arriving late at least once a week. The national survey was conducted online by Harris Poll on behalf of CareerBuilder from November 6 to December 2, 2013, and included a representative sample of 3,008 full-time, private sector workers and 2,201 hiring managers and human resource professionals across industries and company sizes. Running a little late could have big repercussions. One in three (35 percent) employers have fired an employee for tardiness, and 48 percent of employers expect their employees to be on time every day. Thirty-four percent say they allow employees to be late every once in a while, as long as tardiness doesn't become a pattern, and 18 percent don't care how their employees manage their time, just that they get their work done well. "Most employers understand that occasionally things pop up and cause employees to be behind schedule. The trouble comes when tardiness becomes a habit," said Rosemary Haefner, vice president of Human Resources at CareerBuilder. "Employees who are often late should consider regularly checking the weather forecast for their commute, setting up alerts from any public transportation they use, or getting more done the night before so they're not rushed in the morning." Employees tend to run into some roadblocks more often than others. Traffic remains the most common reason employees say they're late (39 percent), followed by lack of sleep (19 percent), problems with public transportation (8 percent), bad weather (7 percent) and dropping the kids off at daycare or school (6 percent).