¥1988 - Manual on
Uniform Traffic Control Devices by FHWA contained the following provisions for traffic signals:
" Section
4B-20 Signal Operations Must Relate to Traffic Flow
" Traffic
control signals shall be operated in a manner consistent with traffic requirements.
"
" Data from engineering studies shall be used to determine the proper phasing and timing for a signal. Since traffic flows and patterns change, it is necessary that the engineering data be updated and re-evaluated regularly. To assure that the approved operating pattern
including timing is displayed to the driver, regular checks including the use of accurate timing devices should be
made.
"
" Sidebar: Removed by the USDOT in 2000 to facilitate automated
enforcement and curtail the growing number court
challenges to cameras. By removing factual foundations
and periodic review, signal timing no longer had any adequacy standards to be met. We believe this violates CongressÕ, factual basis, safety mandate for all traffic control in the Nation.
"