You’ll be pleased to hear the Department for Transport has published a new Research report, Operation of Traffic Signals during Low Demand (4 Oct 2012). I’ll quote and comment as we go along.
“Traffic signal design is a science that has been developed through decades to a point where the maximum efficiency can be squeezed out of the most congested of junctions. Conflicting needs of all road users are measured, evaluated and optimised such that the ever-increasing and varying demands continue to be managed with ingenuity and perfection.” Note the self-congratulation over a questionable claim.
“But roads aren’t always busy.” Get outa here! “In many cases the very justification for signal control is based on a problem that may only exist for a couple of hours each weekday. Even the most congested networks have their quiet moment, yet, in a deserted city at 3 in the morning, signals still cycle for non-existent traffic. Any driver who ventures into this scenario may sit in frustration at a red light while the ‘intelligent’ control system optimises the signals for phantom conflicting demands.” How come the DfT, which gets £12bn a year of public money, has only just become aware of this?
“In other countries various techniques are applied to ‘demote’ signalised junctions to priority mode of operation, for example the flashing amber on main road/flashing red on minor road employed in some States of the USA, or signals that simply turn off overnight as in parts of Europe.” I noticed this when I was in Europe in my teens. It’s taken the experts half a century to wise up! Meanwhile, how many man-hours of needless delay and how many tons of avoidable greenhouse and health-damaging gases have we suffered at the hands of the experts?
On the subject of policy, this wordy passage is ultimately revealing: “… there are opportunities for embracing developing technologies and making minor changes to installation parameters that could reduce installation and maintenance costs and improve the efficiency of LD methods of operation that retain signal control and its intrinsic safety compared with priority operation.”
No mention of no-priority or equal priority! DfT thinking is stuck inside the leprous box marked “priority”. These people really think the choice is only between priority and signal control! You don’t believe me, do you? Well, here is the publication.