page_title: Traffic-light signalling and operation
section_title: Warnings of traffic light ahead
hierarchical_section_title: Traffic-light signalling and operation / Warnings of traffic light ahead
caption_attribution_description: English: This is a flashing warning sign that alternately flashes the amber lights when the traffic signal around the corner is showing a red or amber signal. It continues to flash briefly after the traffic light turns green to allow traffic to start moving. This example can be found on westbound Miller Road leading up to Cornell Road in Portland, Oregon and is accompanied by a 'signal ahead' sign.
context_page_description: The use of traffic lights to control the movement of traffic differs regionally and internationally in certain respects. Note that the color phase commonly known as "yellow" is often referred to, especially in official usage, as "amber"; for consistency this article uses "yellow" throughout.
caption: One example of a preemptive traffic signal warning sign
exif: {"Image Make": "Canon", "Image Model": "Canon PowerShot SD300", "Image Orientation": "Horizontal (normal)", "Image XResolution": "180", "Image YResolution": "180", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2005:03:16 10:54:18", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "196", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "180", "Thumbnail YResolution": "180", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "5108", "Thumbnail JPEGInterchangeFormatLength": "4895", "EXIF ExposureTime": "1/250", "EXIF FNumber": "49/10", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2005:03:16 10:54:18", "EXIF DateTimeDigitized": "2005:03:16 10:54:18", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "5", "EXIF ShutterSpeedValue": "255/32", "EXIF ApertureValue": "147/32", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "147/32", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, auto mode", "EXIF FocalLength": "87/5", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1600", "EXIF ExifImageLength": "1200", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "Interoperability RelatedImageWidth": "1600", "Interoperability RelatedImageLength": "1200", "EXIF InteroperabilityOffset": "2142", "EXIF FocalPlaneXResolution": "50000/7", "EXIF FocalPlaneYResolution": "50000/7", "EXIF FocalPlaneResolutionUnit": "2", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard"}