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Always on tail lights?

skyflyer

Member
Jun 20, 2021
15
1
Slovenia
I've seen this thread about Model S (Can you set Tail lights always on? After rear ended too many times), and I'm wondering if there's a way to have tail lights always on on Model 3? I'm still waiting for mine to arrive, but so far, from reading the manual, I can see that they're set on auto every time you turn on the car. What is interesting is that this section in the manual is marked as "CAUTION":

CAUTION: The rear tail lights are off while daytime running lights are on. Be sure the rear lights are on during low rear visibility conditions (for example, when it is dark, foggy, snowy, or the road is wet, etc.). Failure to do so can cause damage or serious injury.

It would make a lot of sense to allow a user setting to have them always on. I don't understand the rationale that the (day)headlights are always on, but the tail lights are not. The cars are much more visible (granted, subjective) with the tail lights on than off.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,380
11,722
Riverside Co. CA
I believe the answer is the same one that is in the thread you reference, which is, it probably wouldnt help that much, and you would have to turn on the lights each time you drive to do this.

As for "the car is much more visible with tail lights on during the day" for me anyway, I disagree with that. From "OFF" to "Bright" is a lot more noticeable when there is already light than from "ON" to "Brighter".

Tail lights going from OFF to "Brighter" would be more noticeable at night, too, but the trade off there is that without tail lights on, the car itself becomes harder to see at night.
 

skyflyer

Member
Jun 20, 2021
15
1
Slovenia
You have a point, but I respectfully disagree. At least were I'm from, there is a big difference between tail light and stop light (and a 3rd stoplight is mandatory if I'm not mistaken), so confusing tail light for stop light is not something "I" would do.

FWIW, I found this article (from 2012): Why don’t taillights turn on with daytime running lights?

For posterity: Since 2011, DLRs are mandatory for all new cars and small delivery vans in the EU. Trucks and buses followed in August 2012. Vehicles produced before don't have to be retrofitted. (Daytime running light - Mobility and transport - European Commission)

The report (from 2004) concludes:
  • The effects of DRL are greater for fatal accidents than for injury accidents,
    and greater for injury accidents than for property-damage-only accidents.
    Evidence of effects for fatal accidents is, however, highly uncertain.
  • The effects of DRL are likely to be greater at latitudes further away from
    the Equator than at latitudes close to the Equator. The evidence for such a
    relationship is, however, somewhat noisy.
  • It is likely that DRL has a favourable effect on accidents involving
    pedestrians, cyclists or motorcyclists. An adverse effect on rear-end
    collisions has been found in studies of the aggregate effects of DRL. DRL
    combined with switched-off taillights can counteract this effect, as well as
    the use of high mounted brake lights.
I'm not sure how to interpret the last point ;).

Later in the document, they mention: In order to prevent the possible 'masking' of brake lights, which might result in an increase of rear-end collisions, automatic dedicated DRL for headlights should be combined with switched-off taillights. This will also reduce pollution and bulb consumption.

---

It is interesting that you can find different opinions in articles. For instance, this one: Drivers of modern cars with front daytime running lights like these are unaware that their vehicle doesn't have them at the back and are therefore making themselves difficult to see during periods of poor light.

This excerpt (from here (2018)) sums my views pretty well:

An RAC Opinion Panel survey of 2,061 motorists found that more than six in 10 (62%) claimed to see other cars and vans driving in dull overcast conditions without any rear lights on, while they noted these vehicles did have lights on at the front.

RAC road safety spokesman Pete Williams said: “This is potentially a very worrying finding as it implies that many motorists are driving without any rear lights believing that because they have running lights that switch on automatically at the front, they are also on at the rear.

Anyway, I'd love the opt-in approach.

---

Interesting trivia: Daytime running lights originate in the Nordic countries where winter light levels are usually low, even in the day. Sweden was the first country to require them, making them mandatory in October 1977.
 

Gasaraki

Active Member
Oct 21, 2019
2,010
1,255
Syracuse, NY
In the US, the DRL system does not turn on the rear lights. To manually turn on your rear lights, just turn on your headlights or the parking lights.
 

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