New York City started to make changes to its 250,000 street signs Thursday in an effort to comply with new federal regulations.

All of the traffic signs in and around the five boroughs are written in uppercase letters, a feature that the Federal Highway Administration is no longer accepting.

According to the FHA, switching from uppercase letters to a combination of upper and lower will improve safety. Studies show drivers find it easier to read lower case signs, it says.

The city's Department of Transportation says it expects to have 11,000 of the city's quarter million signs changed by the end of this fiscal year. The cost for the changes is estimated at $27.5 million.

DOT officials say the city already replaces about 8,000 signs a year due to wear.

Municipalities across the country have until 2018 to make the changes.

The federal regulations also require a change in street sign's font to a specially designed typeface called Clearview.