Traffic signals are normally found in intersections and other areas where traffic is heavy or there is a high level of risk that different roadway users will cross paths. They are also used to inform users about the roadway that they are approaching or to let them know that they are entering an area with special dangers or restrictions, such as a school zone, construction area or toll area.
Drivers, pedestrians, and bicycle riders must obey these signals, except when an officer is directing traffic. Stop on the stop line if your car is nearest the signal. Some signals change only when a car is at the stop line. If traffic signals are out of order, treat the light as if it was a four-way stop sign.
Traffic Lights
Traffic lights have two advantages over signs. First, because they are illuminated and mounted higher than most signs, they are easier to see from a distance, especially if it is dark or the weather is bad. Second, because they are often timed or linked to sensors in the roadway, they can be programmed to adjust to the changing flow of traffic.
Most traffic lights use the same red-yellow-green color sequence, arranged vertically or horizontally, so that drivers who are color blind or who cannot see part of the signal can still observe them. Lights can be solid, flashing or illuminated arrows.
Red Light – The traffic signal
You must come to a full stop at a red light. You cannot proceed until the light turns green. A flashing red light works like a STOP sign. Come to a complete stop and then proceed when it is safe or you have the right-of-way.
A yellow light warns drivers to slow down. When you see a solid (steady) yellow light it is a warning that green or red will be exhibited immediately thereafter.
A green light means to proceed if safe. If you have been stopped at a red light, make sure that you first look to your left, then to your right, and then to your left again to check for any vehicles or pedestrians that might still be in the intersection. If you are already moving when you approach a green light, continue to move through it with caution. When you see a green light, especially if you have noticed that it has been green for a while, be prepared for the “stale” green light to turn yellow and then red.
Flashing Yellow and Red Light Signals
A flashing red light means the same thing as a STOP SIGN. It is used at dangerous intersections. A flashing yellow light is a caution signal. It is used at, or just before dangerous intersections, or to alert you to a warning sign such as a school crossing or sharp curve. When a yellow light is illuminated with rapid intermittent flashes, drivers of vehicles may proceed through the intersection or past such a signal only with caution. This does not apply at railroad-highway grade crossings. If the yellow light is flashing, slow down, give the right-of-way to other traffic and proceed with caution. Flashing yellow lights often appear by themselves in dangerous parts of a roadway or before an upcoming intersection or hazardous area. If you see a light that appears to be orange or amber in color, you should treat it as a yellow light.
Arrow Lights
Red Arrow: You cannot go in the direction indicated until the light changes to green
Yellow Arrow: When you see a solid (steady) yellow arrow light it is a warning that a green or red arrow light will be exhibited immediately thereafter. If the yellow arrow is flashing, slow down, give the right-of-way to other traffic and proceed with caution.
Green Arrow: A green arrow light means to proceed if safe. If you have been stopped at a red arrow light, make sure that you first look to your left, then to your right, and then to your left again to check for any vehicles or pedestrians that might still be in the intersection. If you are already moving when you approach a green arrow light, continue to move through it with caution. When you see a green arrow light, especially if you have noticed that it has been green for a while, be prepared for the “stale” green arrow light to turn yellow and then red.
Lane-Use Signals
Reversible lanes are designed to allow traffic on high-density commuter roadways to go in one direction at certain times of the day and in the opposite direction at other times of the day. Overhead lane-use signals indicate whether it is clear for you to use the lane or whether the lane is open only to oncoming traffic.
Lane Signals are used:
- To show that a toll booth is open or closed
- To show which lanes are opened or closed
- When the direction of the low of traffic changes during the day.
Red X: A solid RED X indicates that it is open to oncoming traffic. Stay out of this lane! If you accidentally get stuck in a lane with a red X, immediately pull into an adjoining lane with a yellow X or downward-pointing green arrow as soon as it is safe to do so. If this is impossible and there is an open road or driveway off to the side of the road, turn left and go into it as soon as you can to avoid a head on collision.
Steady Yellow X: A steady YELLOW X indicates the driver should safely vacate the lane because the lane is about to be opened to oncoming traffic. Move over as soon as you can do so safely to a lane with a downward-pointing green arrow.
Flashing Yellow X: A flashing YELLOW X indicates the lane is to be used with caution, for left turn movements only.
Green Arrow Pointed Downward: You may drive in a lane indicated which is open to traffic going in your direction.
Busy sections of some freeways also have lane-use signals to warn drivers of problems ahead, such as merging traffic from on-ramps or lane closing because of a collision or construction. If you see a green signal, usually a downward pointing arrow or X, it means that the lane is clear ahead. If the signal is red, it means that the lane ends, is blocked or closed, or has heavy traffic merging into it. As soon as it is safe to do so, move over into a clear lane.
On-Ramp Meters
In and around cities where there is a lot of rush-hour traffic, many freeway on-ramps have special signals to control the number of vehicles merging into the freeway at one time. Similar in appearance to stop lights, on-ramp meters usually have red and green lights (some also have yellow) and allow one or more vehicles in each onramp lane to proceed at intervals. On-ramp meters operate only at peak traffic hours. Otherwise they are turned off to allow cars direct freeway entry when traffic is light.
Warning Signals
Special traffic signals are some times used at school or construction zones and near fire stations and hospitals. These signals usually flash yellow, but in some cases, they may turn to a steady yellow followed by a steady red when pedestrians or emergency vehicles are passing. Some roadways have permanently flashing yellow lights to warn drivers of an approaching curve or exit, dangerous intersection, dividing freeway, or any other place requiring vehicles to slow down.
Variable Message Signs
Many highways have special electronic signs that provide up-to-date information about lane and exit closings, delays, collisions, weather problems, carpooling, and other important items that affect driving conditions. These signs are usually posted in areas with high-density commuter traffic or where bad weather is common. Variable message signs or panels with electronic arrows can also be set up by construction or maintenance crews to help direct traffic or warn drivers of problems on the roadway ahead.
Pedestrian Signals
Pedestrian signals are designed for intersections with pedestrian traffic. Most are mounted just below traffic signals. Pedestrians are allowed to cross when they face a green or white WALK signal or the symbol of a person walking. When they face a flashing orange or red DON’T WALK signal or the symbol of a raised hand, they must wait oat the curb if they have not yet started to cross the street, or they should clear the intersection if they are still in it.
Sometimes pedestrian signals must be activated by hand with special buttons. Do not assume that a pedestrian who approaches a green light at an intersection and is too late to activate the WALK signal will stop. Also, be aware that pedestrians may ignore a DON’T WALK signal or not realize it is on and try to cross in front of you.
Hand Signals for Directing Traffic
Sometimes signal lights malfunction or traffic becomes so heavy at an intersection that police or traffic control officers are called in to direct traffic. This is common at sporting events, concerts, and theme parks where the parking lot entrances and exits merge into the main roadway. Holding the hand up, palm facing outward is the signal to stop. Waving one arm forward is the signal to proceed. Hand signals always take priority over signs and traffic signals.
Fact: Drivers are more likely to be severely injured or killed in a crash at an intersection involving running a red light than any other type of crash.