For UK vehicles as in other countries, the hazard lights flash at the same speed as left/right indicators using the same bulbs. If a car or van is parked in front of another vehicle where only one indicator can be seen and it has hazard lights on, it can look as if the vehicle is about to pull out, particularly if the front wheels are turned towards the traffic. It would seem preferable to have hazard lights flash at double the speed or with some other visual difference to indicate the two very different vehicle states. This may hark back to the days of mechanical flashers, but could be addressed now. Has this ever come up in car indicator design?
1
-
2I have wondered this many times--in my city public buses use their hazard indicators when they are stopped to pick up passengers. They then use their left turn signal to indicate they are going to pull into traffic. When you can only see the street-side of the bus, you have no way of knowing what the bus is actually intending to do unless you can make eye contact with the driver.– Charles WesleyCommented May 1, 2014 at 18:32
Add a comment
|
2 Answers
If the speed at which the blinkers operate are quicker, that means there is a problem in the wiring or with one of the bulbs. More often than not it is a problem with the bulbs. This difference in speed in many GM cars at least translates into a bulb being burnt out and you getting a warning that one of your lights are out. The hazards and blinkers operate using the same circuits and wiring to keep costs down.
What some cars have though, like the Mustang and many city vehicles are switches that can allow control for individual LED or even in some cases halogen bulbs to operate in a sequence. But that is often just attached just before the bulbs and wouldn't make a difference as to whether it was the hazard or the turn indicator.
Vehicles don't often use their hazards so making it use its own circuits and speeds wouldn't make much sense to auto manufactures. As this could have the potential to add about $15-20 per vehicle. Multiple that by a few million vehicles and you are looking at more than half a billion dollars for something people rarely use and won't really care for.
-
Accepted for the possible cost to manufacturers, though if controlled by the car computer there should be no cost after initial development. It may be better to have flashers controlled by a separate device so that hazards work even if the rest of the car is kaput, but even so, the hazard switch or turn switch could be just different inputs to a microcontroller, so I don't see an increase in cost for a modern vehicle.– NickCommented May 3, 2014 at 9:36
-
I've played around with the electronics / lighting on my car. One of the things I was actually looking to modify was how the turn indicators worked. In many cars they operate different amber lights, but in some it is the taillights. They operate on their from their own fuse and own switch on the board, which allows you to add more lights easily or update the entire line. There is a whole new fuse and circuit that would need to be added in order to make this happen. Commented May 5, 2014 at 13:54
"This may hark back to the days of mechanical flashers, but could be addressed now." Yup! This is why older cars have the same flashing rate, they use the same mechanism which is a thermal flasher (http://auto.howstuffworks.com/turn-signal.htm)
When you push the turn-signal stalk down, the thermal flasher connects to the turn-signal bulbs by way of the turn-signal switch. This completes the circuit, allowing current to flow. Initially, the spring steel does not touch the contact, so the only thing that draws power is the resistor. Current flows through the resistive wire, heating up the smaller piece of spring steel and then continuing on to the turn-signal lights. At this point, the current is so small that the lights won't even glow dimly.
After less than a second, the small piece of spring steel heats up enough that it expands and straightens out the larger, curved piece of spring steel. This forces the curved spring steel into the contact so that current flows to the signal lights unimpeded by the resistor. With almost no current passing through the resistor, the spring steel quickly cools, bending back away from the contact and breaking the circuit. The cycle then starts over. This happens at a rate of one to two times per second.
If this is the only wiring mechanism in the car that can make the lights flash, then there would only be one speed.
I have seen many cars on the streets in the US these days that do have different blinking speeds depending on what's happening. From my experience, hazards blink twice as fast as turn signals in Lexus cars.
