[Leica] Re: Traffic management

[lrzeitlin at optonline.net (Lawrence Zeitlin)]

On Jul 20, 2006, at 8:41 AM, Don wrote:

> Nathan,
> A long time back, possibly the late seventies traffic management 
> theory in
> the U.S. was much like you describe in the Netherlands.  Most cities 
> have
> detectors to regulate the flow of traffic.  I very pleasantly recall 
> main
> arteries in Kansas City where if you traveled in a specific speed 
> range you
> could go miles without hitting a red light.  Now they use the sensors 
> to
> manage blocks of traffic by turning lights red to stop traffic from 
> flowing
> smoothly.

Don is right in that modern traffic management practice often operates 
to slow traffic down. Some time ago I was a consultant to the Port of 
New York Authority, the agency that runs many of the bridges and 
tunnels connecting Manhattan to the rest of the universe. There is an 
optimum speed for maximizing the number of vehicles that a particular 
road can handle and it is slower than we like to think. In many cases, 
traffic traveling faster than 30 mph decreases the road's capacity. One 
reason is that the safe spacing distance between cars increases 
disproportionately with increases in speed. The safe distance at 60 mph 
is four times greater than the safe distance at 30 mph. So the traffic 
lights are artfully arranged to slow things down as well as raise the 
frustration level of drivers.

Although I must admit that Atlanta is a perfect example of traffic gone 
crazy. If everything is not to end in a permanent gridlock, Atlanta 
might do well to follow the example of London, charge high fees for 
driving into the corporate limits and ban driving in the central city 
entirely during critical hours. Compared to Atlanta, New York and 
Boston are quite civilized. In the words of a former Southern 
politician, now a nearby neighbor, "I feel your pain."

Larry Z