This is a simple one. I have seen electronic speed limit notices that are changed according to the time of day but they dont really adjust accordong to the immediate traffic density. Generally, the busier the road, the lower the speed limit should be. Imagine an electronic Speed Limit Notice that has an operating range between (say 60-110kms per hour). There would be a traffic density measurement made either by one of those pressure sensitive thingy's they lay across the road or by a radar device. Now, the electonics in the sign (in the absence of traffic) has a bias to drive the display slowly toward its maximum (110). As cars are detected, this input generates a drive to reduce the speed toward 60 . The more cars detected, the greater the drive toward the lower limit. When the traffic subsides, the speed slowly increases back up to 110. It would be quite a simple program and it would allow high speed travel when the roads are quiet.
-- Elitefingerbun, Sep 29 2005

How do you gather that, oh Pa\ve one?

As traffic density increases it is too unsafe to be travelling quicky. Its a common rule in the traffic world. Whereas at midnight and there's no cars around you should be able to safely go faster.

Its quite a boring subject matter, hence the lack of responses.......... but someones gotta do it. I am baking the plain roll as apposed to the cheesy bacon croisant thingy.
-- Elitefingerbun, Sep 30 2005


Not entirely sure this would work as intended, but I'd like to see some real world tests. Or at least some simulations.
-- DrCurry, Sep 30 2005


Baked in the Netherlands. +
-- zeno, Sep 30 2005


If you want to decrease the density, cars with less traffic ahead of them should go faster and cars with more traffic ahead of them should go slower. I say [Elitefingerbun] and [Pa`ve] are both right.
-- kaeru, Sep 30 2005


M25, London
-- Ling, Sep 30 2005


[Ling]'s somewhat over-succinct comment indicates that this exists on the M25 London orbital motorway, and indeed on other UK motorways (parts of the M5, for instance).
-- angel, Sep 30 2005


It seems to me that your premise about speed limits is incorrect --- the busier the road the higher the speed limit should be. For example the M25 carrys more traffic and therefore has a higher speed limit that a small surburban street.

I think that perhaps you have confused a solution and a problem -- speed limits are set for safety and nothing else.
-- madness, Sep 30 2005


//the busier the road the higher the speed limit should be.//
Not quite, I think; a busy urban street should have a lower limit than a non-busy motorway. The speed limit on a particular road should be determined by the degree of risk accompanying higher speed.
-- angel, Sep 30 2005


Are we talking for highway usage only?. On city streets your speed is going to be limited by several factors. Not only the posted speed limit but old people, traffic lights and traffic density.
-- Antegrity, Oct 01 2005



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