Friday, May 16, 2008
Traffic aggravating measures
'Traffic calming measures' is one of those misnomers that has become common in the English language now. You know the things - bollards, speed bumps, narrow sections of road, stripes - all manner of stuff to divert your attention away from the matter at hand -- driving. As far as I can tell, these things just serve to aggravate the average driver. I can tell you it works for me.
If I'm driving down a road with a 20mph speed limit and I see speed bumps, I'd like to believe that I'd be able to drive over them at 20mph. In most cases of course, even the biggest Chelsea tractor couldn't make it over a speed bump at 20mph without rearranging the litter of kids in the back and causing untold damage to the suspension. Surely it can't be that difficult to make a speed bump that you can navigate at the intended speed limit?
Then there's road-narrowing and bollards - both items which typically take me by surprise and cause me to brake because the illusion is that the road is becoming too narrow to drive down. The person following me brakes too - if he's seen me - and suddenly you have a street full of erratic slow-down-speed-up driving. It's all so very unnecessary.
I pity the poor soul who has to ride in an ambulance down one of these hump-ridden streets when they're in cardiac arrest.
I would argue that traffic calming measures typically make those streets more dangerous than they were before. When the neighbourhood kids run out into the street in front of us now, are we going to be concentrating enough to see them, or worrying about the next Everest-sized speed bump?
If I'm driving down a road with a 20mph speed limit and I see speed bumps, I'd like to believe that I'd be able to drive over them at 20mph. In most cases of course, even the biggest Chelsea tractor couldn't make it over a speed bump at 20mph without rearranging the litter of kids in the back and causing untold damage to the suspension. Surely it can't be that difficult to make a speed bump that you can navigate at the intended speed limit?
Then there's road-narrowing and bollards - both items which typically take me by surprise and cause me to brake because the illusion is that the road is becoming too narrow to drive down. The person following me brakes too - if he's seen me - and suddenly you have a street full of erratic slow-down-speed-up driving. It's all so very unnecessary.
I pity the poor soul who has to ride in an ambulance down one of these hump-ridden streets when they're in cardiac arrest.
I would argue that traffic calming measures typically make those streets more dangerous than they were before. When the neighbourhood kids run out into the street in front of us now, are we going to be concentrating enough to see them, or worrying about the next Everest-sized speed bump?
// posted by Chris @ 16:45 0 Comments Links to this post 
Monday, May 12, 2008
Phantom traffic jams
There are a lot of drivers today who need to be taught, it seems, that when they take their foot off the accelerator, their cars will naturally slow down. Too many times I see phantom traffic jams caused by inattentive or inexperienced drivers. The M25 around London is constantly full of these fools.
So what's a phantom traffic jam, you ask? Simple - it's a clogging of the motorway for no reason. Phantom jams are caused not by accidents, road works or any other physical reason but for a mental reason. Someone will come up a little fast behind a car in front, and rather than simply taking their foot off the accelerator, they'll brake a little. Their brake lights come on and the person behind them is then under the impression that they're slowing down properly, as oppose to adjusting their speed. So they brake too, only a little harder. Not much - 2 or 3% maybe. Multiply this scenario back up the line of traffic and eventually you'll get to one car that comes to a complete stop for no reason. Even if that's only for a second or so, it's enough. The phantom traffic jam is born and within minutes, the whole 3 or 4 lanes will be parked.
This java applet shows the effect wonderfully : Traffic Flow Simulator. Choose the ring-road simulation and after a few seconds you'll see a phantom traffic jam form and start to crawl backwards around the road. In this case caused by a single car that slows down fractionally before pulling out from behind a truck. This is exactly what happens on the M25 all the time.
So come on - try not using your brakes from time to time - traffic will flow much more freely.
So what's a phantom traffic jam, you ask? Simple - it's a clogging of the motorway for no reason. Phantom jams are caused not by accidents, road works or any other physical reason but for a mental reason. Someone will come up a little fast behind a car in front, and rather than simply taking their foot off the accelerator, they'll brake a little. Their brake lights come on and the person behind them is then under the impression that they're slowing down properly, as oppose to adjusting their speed. So they brake too, only a little harder. Not much - 2 or 3% maybe. Multiply this scenario back up the line of traffic and eventually you'll get to one car that comes to a complete stop for no reason. Even if that's only for a second or so, it's enough. The phantom traffic jam is born and within minutes, the whole 3 or 4 lanes will be parked.
This java applet shows the effect wonderfully : Traffic Flow Simulator. Choose the ring-road simulation and after a few seconds you'll see a phantom traffic jam form and start to crawl backwards around the road. In this case caused by a single car that slows down fractionally before pulling out from behind a truck. This is exactly what happens on the M25 all the time.
So come on - try not using your brakes from time to time - traffic will flow much more freely.
// posted by Chris @ 14:54 1 Comments Links to this post
Subscribe to Posts [Atom]