Some pedestrian signals integrate a countdown timer, showing how many seconds are remaining for the clearing phase. In the United States, San Francisco was the first major city to install countdown signals to replace older pedestrian modules, doing so on a trial basis starting in March 2001. The United States MUTCD added a countdown signal as an optional feature to its 2003 edition; if included, the countdown digits would be Portland Orange, the same color as the "Upraised Hand" indication. The MUTCD's 2009 edition changed countdown timers to a mandatory feature on pedestrian signals at all signalized intersections with pedestrian clearance intervals ("flashing upraised hand" phases) longer than seven seconds. With the MUTCD guideline allotting at least one second to cross , this indicates that countdown timers are supposed to be installed on roads wider than . The countdown is not supposed to be displayed during the pedestrian "walk" interval ("steady walking person" phase),