SIGNAL2000 Ver 2 - NEMA-Style, Dual-Ring...

SIGNAL2000 Version 2 Offers Method to Handle NEMA-style, Dual-ring Controllers

A troubling problem for some users of the Highway Capacity Manual (HCM) has been an apparent difficulty in representing timings for NEMA-style controllers, especially when there are small differences between the times allocated to left turn phases. Indeed, as Chairman of the Signals Subcommittee for the Transportation Research Board committee which publishes the Highway Capacity Manual, Dennis Strong, the author of the SIGNAL software since its first version in 1974, fully understands this apparent problem. In Version 2 of SIGNAL2000, Dennis has solved this problem directly with a surprisingly simple solution - the ability to represent negative phase times! Although it sounds irrational on the surface, it's not that big of a stretch, as illustrated by the Convert button now available in the dialog when entering or viewing phase timings.

The user can quickly switch his/her view of the phase timings either from the perspective of the HCM (timings by phase) or of a NEMA-style controller (timings by movement). With this feature, timings with negative overlap 'phase' times can be seen easily in the 'by movement' view to see that they are perfectly valid timings for a NEMA-style controller, by virtue of the new dual-ring diagram which is displayed. As noted below, the optimizer in SIGNAL2000 is now also able to take advantage of this new way of representing timings to squeeze the most capacity out of a signalized intersection via timing and phasing optimization.

This produces the only available true-HCM optimization of dual-ring controllers.

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this page last updated April 15, 2019