Safe Speed Forums

I drove down to Warminster from Swindon on saturday along the B roads. I can't remember exactly where we were, but I saw a VAS that was actually really useful. There were actually a pair about 200 yards apart at eather end of a stretch of very narrow road (wide enough to pass another car but too windy to see anything bigger). They detected a vehicle entering the restricted area and warned oncoming traffic of its presence. I was really impressed!

_________________
Science won over religion when they started installing lightning rods on churches.

It does sound like a good idea in principle, and as someone who's in favour of well thought-out VAS installations this one almost gets my vote. The only snag is...


...what happens when the signs have been up for a while and people get used to being forewarned about the presence of an oncoming vehicle, and then one day they head down the road when the signs are out of order? Are we risking exchanging one risk (the present lack of awareness of the narrow lane) with another (the future assumption that if the sign isn't lit, the road ahead must be clear)?

_________________
Chris

I found a useful one near to Didcot in Oxfordshire, It flashed up to say that there was a crossroads ahead. (triangular sign) minor road crossing the one that I was on.

_________________
Speed limit sign radio interview. TV Snap Unhappy
“It has never been the rule in this country – I hope it never will be - that suspected criminal offences must automatically be the subject of prosecution” He added that there should be a prosecution: “wherever it appears that the offence or the circumstances of its commission is or are of such a character that a prosecution in respect thereof is required in the public interest”
This approach has been endorsed by Attorney General ever since 1951. CPS Code

I think the positives outweigh the negatives in this case.

The solution to this is to have it display a different message when the road is clear, rather than no message at all.

How about "Have a nice day" with a big smiley face

Or....perhaps not.

No because a big smiley face means you're travelling below the speed limit

It could be lulling you into a sense of false security viz...
"Welcome to our honey-trap sucker", with a scamera van lurking round the corner.

You'd also need a fail-safe way of detecting the correct operation of the vehicle sensors, so that the "road clear" message could *only* be displayed if the road actually was clear and not occupied by a vehicle which the sensor, for whatever reason, failed to detect. On top of that, if the sensors were proved to be working ok, you'd then also need to prove the sign was displaying the correct message for the sensor inputs received - you don't want a sticking relay, blown triac or whatever being responsible for the last message being held on the sign after the control box has asked for it to be changed...

_________________
Chris

Well there's only so much you can do with sensors, unfortunately.

It's the exact same problem as car ECUs have, sensors fail, but they do so in such a way that they're still in range so are not detected as failure. The MAF and Lambda sensors are the ones that do that on my car and result in the engine running like a bag of crap.

I don't think anyone's found a solution to failing sensors yet, apart from regular inspection/replacement. Which should be a lot easier in this situation than on a car.