84 Chapter 5 — Signals and Signs Pavement Markings Traffic Officers Under special circumstances, an officer may be directing the flow of traffic.  If so, obey the officer’s hand signals instead of the normal traffic signals or  signs. Most traffic officers signal drivers to stop by holding up one hand with  the palm facing the vehicle and giving a long blast on the whistle. The officer  signals drivers to start or to keep moving by motioning with the hand and  giving a series of short blasts on the whistle. At night, the traffic officer may  signal by using a flashlight. White and yellow pavement “markers” are reflective devices used in the  pavement to improve the visibility of marking lines at night when the road is  wet. Red markers indicate wrong-way movements for motorists. In some areas,  blue reflective pavement markers on roadways indicate the location of nearby  fire hydrants or water supplies for fire-fighting units. center lane is reserved exclusively for two-way left-turn movements in both  directions. The two-way left-turn lane must not be used for passing another  vehicle or for the purpose of merging into traffic. The marking for this type of  lane is shown by the diagram below. Yellow lines separate travel lanes moving in opposite directions. White lines  separate travel lanes moving in the same direction. A yellow  skipped  or  broken  line  is used as the center line on a two-lane, two-way road where passing with  care is permitted in both directions. When continuous, double, solid, yellow  lines are the center lines, you cannot cross them to pass in either direction. On  a two-lane road, passing with care is permitted if the skipped-yellow line is in  your lane. Single, solid, white lines are used as right-edge lines along the roadway and  for guiding traffic traveling in the same direction. Single, solid, yellow lines  are used as left-edge lines on divided highways. If you see the reverse, you are  traveling in the wrong direction. On certain multi-lane highways, a special 