Friday, January 20 2017 @ 06:33 PM UTC
Contributed by: B' Spokes
By B' Spokes
National Association of City Transportation Officials released this information: Fixed vs. Actuated Signalization http://nacto.org/publication/urban-street-design-guide/intersection-design-elements/traffic-signals/fixed-vs-actuated-signalization/
The first thing I noticed there is no separate mention of actuation for cars and actuation for pedestrians. There's a world of difference! Automatic detection for cars and try to find the hidden, hard to get to push button for pedestrains. Nor is there mention to mix things up like set timing for cars but make pedestrains be detected. The latter is from what I can tell is something the city standardizes on, unbeiveable.
Now for some quotes and then comments:
"In general, fixed-time signals are the rule in urban areas for reasons of regularity, network organization, predictability, and reducing unnecessary delay. In certain, less-trafficked areas, actuated signals (push buttons, loop detectors) may be appropriate; however, these must be programmed to minimize delay, which will increase compliance."
I have witnessed the city "fixing" a trail crossing button that once pushed would give cross traffic a yellow light to requiring 90 second delay before the yellow light. The funny thing is cross traffic was so light that a good break in traffic would always happen before the 90 seconds was up so you would cross anyway without the light. In comparison a ped signal to cross York Road mid block I have yet to wait more than 45 seconds, Half the time with a lot more traffic (ADT). Basically the city does not accommodate pedestrians so pedestrians do not use accomidations. The city traffic engineers what pedestrians to play the "Mother may I" game so they can laugh when they don't get normal and expected acomidations.
"Actuated signals in general are not preferable because of the maintenance requirements and upkeep of the detection on the street."
Beg buttons have a life of so many pushes and I will assert since there is no acknowledgment that you pressed the button, you bang it again reducing it's useful life in half. I will also mention that this is a complete failure in human design interface. The next issue is does the city have a good maintece in place or is it still relying on complaints from citizens on the 311 system? There was a time when about half the buttons I pushed never worked. That's a crazy number and shows the city needs to do more to keep the buttons they have working.
"Drivers and others at downstream unsignalized intersections benefit from a series of fixed-time signals, as they produce routine gaps in traffic that may be used to turn onto or cross the street. Fixed-time signals help make pedestrians an equal part of the traffic signal system by providing them with regular and consistent intervals at which to cross."
I will note allowing right-on-red a known major source of pedestrian death also reduces this down stream benift. One day I hope they realize for every one the give extra convenience to also delays more than one person, so the net gain is negative. Back to point, there is a benefit to giving pedestrians green walk signs before they pressed a beg button and before making them wait 90 seconds after pusshing. Think of needing to cross two legs of an intersection crosswalk (often required in Marlyland) but crossing one side than the next is not automated so one extra light signal maybe required to complete your journey. Which is fine I guess because it does not violate the traffic engineers rule "The fast mode must go faster and slower modes do not mind going even slower."
"Many existing traffic signals controllers have the capacity to reduce delay, but remain in coordination rather than a free setting. Coordination, paired with long signal cycles, can result in delays of 80 seconds or more, reducing pedestrian compliance, increasing risk-taking behavior, and creating the impression that a push button is either non-responsive or malfunctioning."
And I believe Baltimore standardizes on a delay of 90 seconds for pedestrians. Someone needs to get BDOT unstuck from the 1960s. Oh and stop blaming pedestrians for risky behavor, BDOT is doing all they can to encourage this.