Safe Speed Forums

Consider this. My car has an uncalibrated analogue speedo. There are digits every 20mph, a wide dash at 10 and a narrow dash at 5mph. Going at the wrong speed will see me burnt in the eternal fires of damnation, or something.

I drive a tractor. It has a digital LCD speedo that give MPH or KPH to 1 decimal place (could do with 2 decimal places). Under the dash programming section in the hand book, there are calibration numbers for 14 of the most popular tyre sizes and a further section on dynamic calibration. IE, measure a distance, mark it, and drive along it untill the dash is happy it knows how many times a wheel turns over distance X.

This machine also has a radar. Has your car?

In the hand book there are 5 speed charts giving speed to 2 decimal places for a total of 560 gear and tyre combinations. My machine has 32 forward and 24 reverse gears and I feel hard done by.

The machines I use behind this tractor each have there own operating parameters and forward speed is a significant part. But like driving on the road, not the whole story. Now I, as a responsible and resonably experienced operator am expected to be able to judge the conditions and select an appropiate speed. I may be changing gear several times from one end of a field to the next.

If I select an inappropiate speed I could overload the engine, damage the machine I'm pulling or damage the crop I'm harvesting. When my college uses his sprayer, it is so sensitive to forward speed it has to have it's own speedo, off it's own wheels so the control box can adjust the application rate as the speed changes. Speed is critical in any calibration of spreading and spraying quiptment.

So after a day at work judging my speed I get in the car to go home and am deemed no longer capable of using any judgement what so ever.

I hear what you are saying!! Yet there are people who would say that, while you may think you know what you are doing, they know better and they beleive that everybody else out there doesn't, therefor the big red circles on the side of the road (or lack thereof) need to do the thinking for them and you.

An extremely patronising idea, I agree, but isn't it interesting how many people there are who actually do know what they are doing, but will be told again and again by people with vested interests in the money to be made out of the current system that they don't.

The company I work for manufactures electronic contols for on and off highway aplications. This includes transmission controls and instrument clusters for Tractors

In terms of Technology tractors have by far the most complex systems. Hitch control, ground radar, auto guidance etc. Driving a tractor is a highly skilled operation. You have to stay on the ball all the time.

Unfortunatly there are people on the roads who are not so skilled. And you must see them all the time. We seem to have laws that are designed to operate at the lowest common denominator, the bad driver.

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Speed camera policy Kills

My kit car also has a digital LCD speedo, that has 100's of settings for wheel to axle rotation.

Which was all calibrated to the given spec, the speedo also tells me to the same degree of decimal places, the speed i am at.

However, during VOSA calibration check, i only just scraped in on the second attempt.

Digital speedo's are no more accurate than conventional geared speedo's.

They just give you a better impression, that they are.

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Steve