Brake lights currently show the use of the braking system. This is now a rather archaic way of conveying the actual information that the lights are really there for - that the vehicle is slowing down. (hey, lets have rear lights to show I am changing channel..."now playing"...)
Brake lights should be connected to both the braking system and to an accellerometer. When the accellerometer detects a drop in speed (fit it the right way around, folks!) the brake lights should also be activated.
This allows normal braking to be shown but also covers scenarios when vehicles slow down rapidly - e.g. downshifting, coasting uphill etc etc.-- timbeau, Jan 14 2004 Kickstarter: VeloCityLights http://www.kickstar...ke-lig?ref=categoryspeed-indicating brake light for bicycles [jutta, Dec 17 2013] But that'd take all the fun out of downshifting! (Otherwise, a good idea.)-- kropotkin, Jan 14 2004 I agree with kropotkin. Downshifting can be a fun way to give a little wake-up call to the driver behind you.
Last time I used this little trick, I'd been driving like a bloody fool in an '89 Taurus SHO late one evening on US 22 in Western PA. I must have blown past the officer at about 120 mph (200 kph for you metric folks). He never turned on his lights, but by the time he caught up with me I was doing a more reasonable 45 mph after exiting the highway. I was heading into a 35 mph zone and he was riding my tail pretty badly (I couldn't see his headlights in the rear-view, he was so close), so I dropped it into 1st gear (the car redlines at 42 mph in 1st) and let the clutch slip. The engine roared, and the car's weight lurched forward as I slowed quickly.
The officer chose that moment to turn on his lights. I pulled over, and I think he was almost as nervous as I was after my little downshifting trick had caught his attention. He asked for documentation, which I provided, and asked me if I'd been drinking. Disappointed to find that I hadn't been, he sent me on my way.
Now, either he had followed me out of his jurisdiction or he had lost line-of-sight, so I drove away without losing my license but having learned that you shouldn't drive speeds at which you would mind getting a ticket (or paying the other consequences). He learned, um, something or other about not following too closely because the a-hole might downshift and make you hit the brakes.
So, yeah, um, what was the point again? Oh, yeah, decelleration lights. In an ideal world, I'd agree. In this world, I'd like a switch to return the behavior to normal brake lights, in case somebody needs a gentle reminder regarding safe following distances.-- GargantuChet, Jan 14 2004 I agree with kropotkin, it would take the fun out of downshifting, I had lots of fun slowing my dad's Vauxhall Nova (for US read: Opel/GM brick-shaped crapmobile) to a crawl without using the brakes when taking left turns (for US read: right). I noticed that it's far more effective if you leave the engine at idle and gradually let the clutch out than if you try and get the right engine speed as if you were downshifting normally.-- squigbobble, Jan 14 2004 Ouch! You'll want to watch slippling the clutch too much, squigbobble -- like with brake pads, friction will wear out a clutch. I've heard it said that slipping a clutch for longer than one second at a time will drastically shorten its life.
For the best in clutch life (and ease in downshifting), double-clutch it -- depress the clutch pedal, throw the shifter into neutral, and let the clutch back out. (Actually, if the engine isn't dragging or being dragged by the car, you can ease the car into neutral with a minimum of pressure on the shifter, and without touching the clutch). Rev the engine to the target RPM for the gear into which you're planning on shifting. Hit the clutch, ease the shifter into gear, and let the clutch back out. Minimal clutch slippage will occur, and since you got the transmission internals to spin at roughly the desired speed it'll be easier to shift into gear. This extends clutch and transmission life, and it's fun at hell.
Of course, double-clutching does require a good feel for what the correct engine speed at a given RPM would be. It's good to think in terms of "mph/kph per 1000 RPM". For example, to shift my aforementioned SHO from fifth into third while doing 65 mph, I'd press the gas just enough to keep the engine from slowing the car down and ease the shifter into neutral. Then, since third gear had a ratio of about 15 mph per 1000 rpms, I'd rev the engine to about 4300 rpm, hit the clutch, shift easily into 3rd, let the clutch back out, and mash the gas.
On a good day, I'd just rev the engine to the appropriate speed, and ease the shifter into gear without using the clutch at all. This is easy on the clutch, since you never disengage it, but it's really hard on the transmission, since the internals bear the friction imposed by matching the engine speed to the speed of the wheels.
Hmmm... clutches... it's quite a shame that Americans are afraid to drive cars with normal transmissions anymore. Most cars no longer offer the option to have anything but a slushbox inside. Ugh.
So, yeah, um, deceleration and stuff. Cheers.-- GargantuChet, Jan 14 2004 I’d like to have a button wired in parallel to my brake pedal, so I can activate my brake lights whenever I want to, giving the idiot riding my bumper a scare without endangering myself.-- ldischler, Jan 17 2004 //I’d like to have a button wired in parallel to my brake pedal, so I can activate my brake lights whenever I want to, giving the idiot riding my bumper a scare without endangering myself.//
Your E-brake doesn't activate the brake lights. So just use that. It works really well for me....well, for my husband, I don't quite have the driving nerve to do that. ;)-- babyhawk, Jan 17 2004 Eh? That doesn't make any sense.-- ldischler, Jan 17 2004 your emergency brake. It will not activate the brake lights.-- babyhawk, Jan 17 2004 Yes, but the point is, I want to activate them, see? Without having to tap the brakes. Thus it would be wired in parallel.-- ldischler, Jan 17 2004 oh, there is where I was confused. I thought you wanted to activate the brakes without the lights, not the lights without the brakes. sorry for the confusion. ;)-- babyhawk, Jan 17 2004 I agree that the driver behind should have adequate warning of deceleration, but this should be covered by good driving practices - not downshifting and covering the brakes properly.
The reason why the standard system works best is because the following driver can see when brakes need to be applied, otherwise an increase in gradient might cause the following driver to apply brakes.-- FloridaManatee, Jun 03 2004 Great idea... consider a light which has variable brightness depending on the braking speed.-- selbedo, Jun 04 2004 Yeah, we did that one (about four hundred times).-- angel, Jun 04 2004 “Officer, why'd you rear-end my car?”“Your brake lights didn't work.”“Well, they did before you smashed them.”-- bristolz, Jun 04 2004 Baked in some Mercs. Above a certain speed a rapid removal of the foot from the accelerator pre-empts the fact that your next action will be to stamp on the brake, so it turns the brake lights on.
Of course, the rest of us dont know that so a jittery driving style could look like you are a brakepad-burning fool and on the motorway...-- Jim'll Break It, Mar 23 2005 Sorry to see this is already baked (for me) but I thought of this yesterday. In more detail, the decellerometer could be a simple rheostat and switch attached to a swinging weight (as in seatbelt catches of old). When you both apply the brake and decel (for you downshifters, this will preserve your stealth) the light will come on. The greater the rate of decelleration, the brighter the light, or the greater area of the light will be lit.-- wittyhoosier, Feb 19 2007 Indeed; several variations of this have appeared over time. Most of them receive a pastry from me. I too drive a manual transmission vehicle, and seldom reach for the brake pedal until I have sifted down around 2nd gear. [+]-- ed, Aug 21 2007 Now, that's a great idea...I'm putting on on my car this week end. I notice, here in Las Vegas, Nevada, the busses have this.....when they are decellerating without braking, little yellow lights begin to flash alternatively.-- Blisterbob, Aug 21 2007 Much too sensible an idea for the halfbakery.-- Cosh i Pi, Aug 22 2007 random, halfbakery