View Single Post
Old 10-14-2007, 04:19 PM   #3 (permalink)
EnglishPaul
Still no avatar
 
Join Date: Sep 2007
Location: Sheffield
Posts: 1,314
OS: XP SP2


Blog Entries: 9
Re: Truck speed limiters

Thanks Kodi.
I am of the other opinion, however.
What happens in the UK is that trucks are all limited to 56mph, and so overtaking is dependent upon what bias the limiter is set at (and they seem to vary quite widely) and what the gradient is.
In my opinion what happens is this: on our 3 lane motorways, of which trucks are banned from lane 3, when 1 truck overtakes another it takes a long time (due to the small differential between limiters). While this overtaking is going on, cars (traveling on a motorway at 70mph by law (or 85mph in reality)) have a huge speed differential with the overtaking trucks. Soon cars get stuck behind the trucks and in desperation pull out in to lane 3 at about 60mph which is still 25mph below the norm. Existing cars in lane 3 then need to brake, and later cars either brake too much and set a rarefaction down the motorway that causes a jam, or brake too little and go into the back of another car.
Thus the motorways work less effectively as cars get jammed up.
Without speed limiters, speed differentials could be higher, overtaking of trucks would thus be shorter and the motorway would see less holdups.
Furthermore, I notice that since I had a speed limited fitted on the 7.5t truck I drive since christmas (change in the law), I now drive far closer to other trucks to minimise the inconvenience to others when overtaking. Such small gaps when following trucks can't be safe- especially as you can't see over a truck to the road ahead. So my driving has become less safe.
Finally, in vehicles with cruse control you don't even need to operate the accelerator, and so for long motorway journeys all you are doing is steering. And if that is not a recipe to fall asleep or not concentrate, I don't know what is.

I am glad that with limiters, the operators can not force drivers to brake the speed limits. But it doesn't work that way. Instead the temptation is (for people like me who do not know how to defeat the limiter) to make up time by diving at 56mph on all roads whether they be past a school or not. On balance I can't see limiters are a good thing.
[Although I do concede that the limit of 56mph is better for fuel economy and therefore better for the environment. But what speeds trucks should be aloud to drive at is a new thread.]
EnglishPaul is offline   Reply With Quote