Anchor ads are not supported on this page.

4S Ranch Allied Gardens Alpine Baja Balboa Park Bankers Hill Barrio Logan Bay Ho Bay Park Black Mountain Ranch Blossom Valley Bonita Bonsall Borrego Springs Boulevard Campo Cardiff-by-the-Sea Carlsbad Carmel Mountain Carmel Valley Chollas View Chula Vista City College City Heights Clairemont College Area Coronado CSU San Marcos Cuyamaca College Del Cerro Del Mar Descanso Downtown San Diego Eastlake East Village El Cajon Emerald Hills Encanto Encinitas Escondido Fallbrook Fletcher Hills Golden Hill Grant Hill Grantville Grossmont College Guatay Harbor Island Hillcrest Imperial Beach Imperial Valley Jacumba Jamacha-Lomita Jamul Julian Kearny Mesa Kensington La Jolla Lakeside La Mesa Lemon Grove Leucadia Liberty Station Lincoln Acres Lincoln Park Linda Vista Little Italy Logan Heights Mesa College Midway District MiraCosta College Miramar Miramar College Mira Mesa Mission Beach Mission Hills Mission Valley Mountain View Mount Hope Mount Laguna National City Nestor Normal Heights North Park Oak Park Ocean Beach Oceanside Old Town Otay Mesa Pacific Beach Pala Palomar College Palomar Mountain Paradise Hills Pauma Valley Pine Valley Point Loma Point Loma Nazarene Potrero Poway Rainbow Ramona Rancho Bernardo Rancho Penasquitos Rancho San Diego Rancho Santa Fe Rolando San Carlos San Marcos San Onofre Santa Ysabel Santee San Ysidro Scripps Ranch SDSU Serra Mesa Shelltown Shelter Island Sherman Heights Skyline Solana Beach Sorrento Valley Southcrest South Park Southwestern College Spring Valley Stockton Talmadge Temecula Tierrasanta Tijuana UCSD University City University Heights USD Valencia Park Valley Center Vista Warner Springs

Tail-light red

Hey Matt:

Why are nearly all automobile tail lights the exact same shade of red? Does it have a name?

Sponsored
Sponsored

-- Matt, on 805 southbound

Commuter-coma Red. Panic-stop Red. Screeeech! Red. Look Out! Red. Hey, You Jerk, You'd Better Have Insurance! Red. There are lots of good possibilities. But since we're dealing with engineers, not poets or lipstick manufacturers, the color is called SAE J578c. Well, actually it's called Red, but the specific red is defined in the Society of Automotive Engineers standard number J578c. It all begins with the feds, as if I had to tell you that.

All brake lights and tail lights are some shade of red because the National Highway Traffic Safety Commission sez they have to be. But rather than leave the definition of red up to our imaginations-- no, you can't put cool, flamingo-pink brake lights on your classic Thunderbird-- they give us Standard 108, Part 571 of the Federal Motor Vehicle Safety Standards and Regulations. And Part 571 sez the red brake lights must meet the requirements of SAE J578c. And SAE J578c sez the red in question is that particular shade defined as "red" on the CIE 1931 2-degree Observer Chromaticity Coordinates chart. The chart maps out the visible light spectrum by wavelength and intensity, like a deconstructed rainbow.

Basically, the feds want the brake lights to be a color we all can agree is "red" and to be bright enough to be visible for a certain distance in order to "enhance the conspicuity of motor vehicles on public roads." Well, if you're anything like me (though of course you're not) right now you'll be leaping out of your chair and yelling, "Conspicuity? There's no such word as conspicuity!" Then you'll go to the dictionary and find out you're wrong.

So anyway, where were we. Oh yeah. The chromaticity chart. It shows what that government-approved light will look like. The strength of the light source in the tail-light housing and the red acrylic resin lens must combine to meet J587c standards as measured from outside the housing. Ergo, we all end up looking pretty much the same from behind.

Here's something you might be interested in.
Submit a free classified
or view all
Previous article

Gonzo Report: Save Ferris brings a clapping crowd to the Belly Up

Maybe the band was a bigger deal than I had remembered
Next Article

Bluefin are Back! – Dolphin Scores on San Diego Bay Halibut, and Corvina Too

Turn in Your White Seabass Heads – Birds are Angler’s Friends

Hey Matt:

Why are nearly all automobile tail lights the exact same shade of red? Does it have a name?

Sponsored
Sponsored

-- Matt, on 805 southbound

Commuter-coma Red. Panic-stop Red. Screeeech! Red. Look Out! Red. Hey, You Jerk, You'd Better Have Insurance! Red. There are lots of good possibilities. But since we're dealing with engineers, not poets or lipstick manufacturers, the color is called SAE J578c. Well, actually it's called Red, but the specific red is defined in the Society of Automotive Engineers standard number J578c. It all begins with the feds, as if I had to tell you that.

All brake lights and tail lights are some shade of red because the National Highway Traffic Safety Commission sez they have to be. But rather than leave the definition of red up to our imaginations-- no, you can't put cool, flamingo-pink brake lights on your classic Thunderbird-- they give us Standard 108, Part 571 of the Federal Motor Vehicle Safety Standards and Regulations. And Part 571 sez the red brake lights must meet the requirements of SAE J578c. And SAE J578c sez the red in question is that particular shade defined as "red" on the CIE 1931 2-degree Observer Chromaticity Coordinates chart. The chart maps out the visible light spectrum by wavelength and intensity, like a deconstructed rainbow.

Basically, the feds want the brake lights to be a color we all can agree is "red" and to be bright enough to be visible for a certain distance in order to "enhance the conspicuity of motor vehicles on public roads." Well, if you're anything like me (though of course you're not) right now you'll be leaping out of your chair and yelling, "Conspicuity? There's no such word as conspicuity!" Then you'll go to the dictionary and find out you're wrong.

So anyway, where were we. Oh yeah. The chromaticity chart. It shows what that government-approved light will look like. The strength of the light source in the tail-light housing and the red acrylic resin lens must combine to meet J587c standards as measured from outside the housing. Ergo, we all end up looking pretty much the same from behind.

Comments
Sponsored
Here's something you might be interested in.
Submit a free classified
or view all
Previous article

Maoli, St. Jordi’s Day & San Diego Book Crawl, Encinitas Spring Street Fair

Events April 25-April 27, 2024
Next Article

Normal Heights transplants

The couple next door were next: a thick stack of no-fault eviction papers were left taped to their door.
Comments
Ask a Hipster — Advice you didn't know you needed Big Screen — Movie commentary Blurt — Music's inside track Booze News — San Diego spirits Classical Music — Immortal beauty Classifieds — Free and easy Cover Stories — Front-page features Drinks All Around — Bartenders' drink recipes Excerpts — Literary and spiritual excerpts Feast! — Food & drink reviews Feature Stories — Local news & stories Fishing Report — What’s getting hooked from ship and shore From the Archives — Spotlight on the past Golden Dreams — Talk of the town The Gonzo Report — Making the musical scene, or at least reporting from it Letters — Our inbox Movies@Home — Local movie buffs share favorites Movie Reviews — Our critics' picks and pans Musician Interviews — Up close with local artists Neighborhood News from Stringers — Hyperlocal news News Ticker — News & politics Obermeyer — San Diego politics illustrated Outdoors — Weekly changes in flora and fauna Overheard in San Diego — Eavesdropping illustrated Poetry — The old and the new Reader Travel — Travel section built by travelers Reading — The hunt for intellectuals Roam-O-Rama — SoCal's best hiking/biking trails San Diego Beer — Inside San Diego suds SD on the QT — Almost factual news Sheep and Goats — Places of worship Special Issues — The best of Street Style — San Diego streets have style Surf Diego — Real stories from those braving the waves Theater — On stage in San Diego this week Tin Fork — Silver spoon alternative Under the Radar — Matt Potter's undercover work Unforgettable — Long-ago San Diego Unreal Estate — San Diego's priciest pads Your Week — Daily event picks
4S Ranch Allied Gardens Alpine Baja Balboa Park Bankers Hill Barrio Logan Bay Ho Bay Park Black Mountain Ranch Blossom Valley Bonita Bonsall Borrego Springs Boulevard Campo Cardiff-by-the-Sea Carlsbad Carmel Mountain Carmel Valley Chollas View Chula Vista City College City Heights Clairemont College Area Coronado CSU San Marcos Cuyamaca College Del Cerro Del Mar Descanso Downtown San Diego Eastlake East Village El Cajon Emerald Hills Encanto Encinitas Escondido Fallbrook Fletcher Hills Golden Hill Grant Hill Grantville Grossmont College Guatay Harbor Island Hillcrest Imperial Beach Imperial Valley Jacumba Jamacha-Lomita Jamul Julian Kearny Mesa Kensington La Jolla Lakeside La Mesa Lemon Grove Leucadia Liberty Station Lincoln Acres Lincoln Park Linda Vista Little Italy Logan Heights Mesa College Midway District MiraCosta College Miramar Miramar College Mira Mesa Mission Beach Mission Hills Mission Valley Mountain View Mount Hope Mount Laguna National City Nestor Normal Heights North Park Oak Park Ocean Beach Oceanside Old Town Otay Mesa Pacific Beach Pala Palomar College Palomar Mountain Paradise Hills Pauma Valley Pine Valley Point Loma Point Loma Nazarene Potrero Poway Rainbow Ramona Rancho Bernardo Rancho Penasquitos Rancho San Diego Rancho Santa Fe Rolando San Carlos San Marcos San Onofre Santa Ysabel Santee San Ysidro Scripps Ranch SDSU Serra Mesa Shelltown Shelter Island Sherman Heights Skyline Solana Beach Sorrento Valley Southcrest South Park Southwestern College Spring Valley Stockton Talmadge Temecula Tierrasanta Tijuana UCSD University City University Heights USD Valencia Park Valley Center Vista Warner Springs
Close

Anchor ads are not supported on this page.