KS-RATIO, originally the Finnish name KSUHDE, is a program
for evaluation of traffic signal feasibility. It is based on the well-known
theory of the V/C (volume/capacity)
-ratio presented in most traffic signal planning handbooks.
KS-RATIO does not compute the average delays or stops in
traffic signals. On the contrary, it describes the effect of each vehicle approach and
pedestrian crosswalk to the V/C-ratio of
the traffic signal control. That is why KS-RATIO is very suitable for comparison
of different planning schemes.
KS-RATIO is based on the modern signal group
orientated control principle. So it is more flexible than programs based on
the older stage-orientated signal control.
The most distinguished feature of KS-RATIO is to find
critical movements of signal control - vehicle approaches and pedestrian crosswalks
which are all together conflicting - these can not have green signal
simultaneously - and these needs together most green time. The sum of
the green time needed for
the critical movements is used to compute
the junction V/C -ratio, which describes the total effectiveness of signal
control in the junction. The method is described (in Finnish) for example
in Liikenne ja väylät II, Suomen Rakennusinsinöörien liitto RIL
165-2, page 378, Helsinki 1988 and Tiehallinto LIVASU-95
Liikennevalot (page 7C-4), Helsinki 1996.
The first version was made with Fortran in 1978.
The second version programmed with Microsoft QBasic was developed
in 1988-1996. The last active version was KSUHDE 2.27
The third version is programmed with JavaScript, VbScript and ASP
in Internet environment. The program includes also HTML-Help
(in Finnish only).
