Safety Sense braking: Do the brake lights turn on?

You could always get someone to follow you and record for yourself just to be sure, or take a total strangers' word on it

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The brake lights turn on whenever you brake by pressing the brake pedal, by decreasing the speed on RCC, waiting on read light when HOLD is activated...

 

The manual suggests the rear brake lights are activated when strong regenerative engine braking is occurring

 

Wouldn’t the brake lights have to come on when automatic braking features are activated. Otherwise it would be a major safety hazard for those driving behind you. Please let us know what you find out.

 

FWIW; my understanding of the system. No brake lamps if the system zeros out the accelerator pedal (ie. coasting). Rear brake lamps light up if ABS pump activates to apply brake force (actual braking). I haven't had a chance to test this. Just my interpretation of the system as printed in the manual.

 

It's simpler than it seems.

If any of the safety systems need to use the brakes to slow or stop the car, then the stop lamps illuminate.

The safety systems don't know anything about the regen vs. hydraulic brakes- there's no need. They just ask for more braking or less braking and let the brake controller worry about the details.

 

Yep, agree with your assessment and is actually what happens from observation with my XLE.

 

Is the specific to your Prime manual, or is it in the non-Prime manual too?

 

I would assume it's the same system; otherwise Toyota would have to resubmit test results instead of telling them it's the same safety system; only in a different model.

Engineering and safety testing x2 for effectively similar cars would have to be submitted to the NTSB for certification if they were materially different systems.

 

Probably this only applies to the Regen-Boost mode (pg 261):

 

Pg 331 Dynamic Radar Cruise Control - "preceding vehicle driving slower than the set speed is detected...the stop lights will come on at this time"

 

Good to know!

On the same line, does anybody know the rules for the "place hands on steering wheel" warning we, sometimes get? I was driving a friend around and he wanted to see it....but no matter how long I left my hands off the steering wheel, the stupid thing wouldn't put out the warning...making me out to be a big liar!!

Smart a** Toyotas!!! ;-)

 

There are enough differences, with the Prime having greater electrical capacity than the non-Prime, that I would not make that same assumption.

At least for my Gen3 non-Plug-in, I'm not aware that regen or engine braking will ever light up the brake lights. It isn't strong enough to need to, it can't provide as much braking as downshifts in manual transmission vehicles that also don't activate the brake lights. And I'm not aware of Gen4 non-Primes doing any different.

Driver assist features that activate the hydraulic friction brakes do need to light up the brake lights.