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Street light wire theft is a big and expensive problem for public agencies.  A world wide shortage of copper led to a dramatic increase in the salvage value of copper wire, starting in about 2006.  Coupled with the economic downturn in the US, a very unorganized but persistent wave of wire theft began.  With the slow-down of the building boom in China in about 2014-15, the price has since dropped off substantially but is still higher than historical averages.  Here is a snap shot of the curre...

There are three observations I’d like to share with the folks in the professional community who are involved in traffic signal coordination, and I’m hoping to hear if others have noticed anything similar.  

First, when implementing coordination plans that have been developed with an optimization model, I often find ways to improve operations during the fine tuning step.  The last step of the process is to input the final timing settings back into the model and run it one last time to ge...

http://howtoinstructions.tips/this-dancing-crosswalk-signal-is-designed-to-keep-pedestrians-safe-and-happy/

And here is an alternative from Germany:

http://www.youtube.com/watch?v=C3Ozz6_pdMI

Terminal compartments are part of a traffic signal installation that allows circuits to be connected without using splices in pull boxes.  The picture below shows what is inside.  There are two pictures of the same terminal strip, taken from either side.  In the first picture you will see the posts numbered from 1-12.  The posts go all the way through.  In the second picture you can see single wires attached to 6 of the posts.  You can attach up to 3 wires per side, or 6 wires total. 

So...

• LED Signal Heads
  • Re-lamp every 5-10 years
• Video Detection Systems (VIDS)
  • Annually test aiming and accuracy o...

Question:  What are the best procedures for installing and maintaining Battery Backup Systems? 

•  Battery life seems to be about 5 years.  Costs to repair batteries is about $1...

"A road safety charity has warned motorists that glare from the sun creates more dangers than driving at night or in bad weather.  From the UK, the Institute of Advanced Motorists (IAM), Neil Greig, IAM director of policy and research, said: ''We can't change the position of the sun, or the need to travel at certain times, but there are simple steps you can take to ensure you're prepared for these conditions.

Making good choices is key to the theme "Don't be Driven to Distraction - Drive to Arrive" for the 10th Anniversary of Put the Brakes on Fatalities Day - October 10, 2010

Try to think of some of the significant things you have done that started with an initial action, the first step or the first day. Maybe it was a case where you quit smoking or even better yet put away your cell phone after nearly crashing into car with a mother and children in it that you said "never again will I use a cel...

The new CA MUTCD (California Manual on Uniform Traffic Control Devices) has been released.  There are two important updates relative to traffic signal operations.  First is the bicycle timing requirements, which have been adopted as presented in draft form.  (See post dated Dec 3, 2009).  The second is pedestrian Walk and Flashing Don’t Walk times.  The new standard is not substantially changed from before, but a recommended walking speed of 2.8 feet per second has been added when slow movi...

Question:  My City has been responding to calls lately about bikes not getting detected at traffic signals.  We use the Type D loop at the front of all our Stop Bar detection, which is supposed to pick up bicycles.  Do we need to connect that front loop to its own Detector Cable? 

Answer:  The typical detector loop has a Type D loop right at the stop bar (the bike loop), and three Type A loops connected in series-parallel extending away from the intersection.  As you noted, this style of de...

Question:  How does a CCTV surveillance camera get tested before installation? 

Answer:  Republic ITS is an electrical contractor that installs closed circuit television (CCTV) cameras, either through maintenance or installation contracts.  We perform a simple bench test before installing cameras.  The photos below show a recent test of Cohu cameras, using a simple wood support, a...

Question:  How does an IISNS mounting work? 

Answer:  Internally Illuminated Street Name Signs are typically mounted under a traffic signal mast arm.  Older style signs are typically light be fluorescent tubes and new style signs are LED.  The mountings connect the sign housing to the mast arm, and are hinged so the sign can swing in the wind and reduce what would otherwise be a large wind load.  The photo shows a close up of an IISNS from Alameda County.

There is a base that connects...

Question:  Will I get a ticket if I drive in a solid-white painted lane while exiting a freeway?  I drive off of 85 South and want to turn right onto Blossom Hill Rd. There is plenty of room to turn right and tons of people do it all of the time but I don't know if it's legal or not.

Answer:  The photo shows the turn you are asking about.  People are using the shoulder as a second right turn lane.  The vehicle code says it is legal to use the shoulder for right turns but only for 200 feet in...

Question:  Some traffic signals in snow country with LED lamps are getting clogged with snow.  Are there any new products to address this problem? 

Answer:  The lower wattage of LED traffic signal heads compared to incandescent also means the lamps generate less heat.  This allows snow or ice to form on the head and sometimes block the display.  In at least one case in Wisconsin, it has become a legal issue.  See http://www.todaystmj4.com/news/local/79008352.html

McCain Traffic Supply has d...

Question:  I travel the same route to work on the same streets and at approximately at the same time 5 days a week. So here it is a holiday week and yes, traffic is lighter but then that gets me into work earlier. Why is it sometimes left-hand signals will be quick and other times they TAKE FOREVER. Is it lighter traffic not triggering the signal or is it time of day?

Answer:  The easy part of your question is the very last.  A traffic signal detector, with very few exceptions, is binary.  Y...

Question:  When Caltrans knows of a big traffic congestion problem, for example at 880 and Stevens Creek (the exit to Valley Fair and Santana Row), what organizations are involved to fix that kind of a big congestion problem? How long would it take, once approvals were passed, would it take to construct the solution?

Answer:  Great question for Mr. Roadshow of the SJ Mercury News.  Gary Richards just published some great news for you (posted 12/17/09):

“Bay Area transportation planners ha...

Question:  I’ve been told Caltrans recently issued new guidelines on accommodating bicycles at signalized intersections.  Where can I find the details?

Answer:  In August, 2009, Caltrans issued a Policy Directive about new requirements for bicycle detection at signalized intersections and new guidelines for traffic signal timing to accommodate bicycle travel speeds.  You can find the full document at http://www.dot.ca.gov/hq/traffops/signtech/signdel/policy/09-06.pdf.  The document describ...

Question:  My City has a traffic signal with a protected left turn that is to be converted to a permissive.  There is a mast arm for this move which currently has a signal heads for the left turn phase and through phase.  I have been told there is a product available from Pelco called the Astro-Brac that I can use to replace both the existing heads with one doghouse head, and mount it in between the current head locations.  What more can you tell me? 

Answer:  Pelco has a product called AB-0...

Question:  Freeway access to Valley Fair Mall in San Jose is so bad I never shop there.  Why can’t someone build new ramps from northbound I-280 to Winchester Boulevard? 

Answer:  The brief answer is that the on-ramps to northbound I-280 from I-880 would be too close to these new off-ramps and create a dangerous weave pattern in the traffic.  Note that in the diagram below the traffic streams from A to D and from B to C have to cross within the distance labeled as the Weaving Area.  As lon...

Question:  How do the radio stations and TV stations know when there are traffic jams? Are there sensors in the street itself? Do they all go to websites where all of the cameras we see on the signal lights are coordinated and the information goes to one place? Is there one centralized place where all of these people go to for their information? Do they have to call or go to all the different websites?  Is it true what you see on TV or in the movies how people can hack into one place and see ...

Question:  I have two new signal systems about 500’ apart and speed limit is 30mph.  I worried about there would be visibility conflict between these two signals.  So, in what situation the louvered signal head is required?

 Answer:  The issue with closely spaced intersections is that the driver wating at the stop bar of the first one might see a green at the second one and start driving, even when the closer signal display is still red.  The Caltrans traffic manual had a guideline to rest...

Question:  My City has recently installed a new traffic signal.  There is a curve in the southbound approach that limits the visibility of the signal heads.  How do I know if I need a Supplemental head or not?    

Answer:  Chapter 4 of the California MUTCD has your guidance.  First determine your travel speed on the approach.  Then look up the minimum visibility requirement in Table 4D-1 of the CA MUTCD http://www.dot.ca.gov/hq/traffops/signtech/mutcdsupp/pdf/camutcd/CAMUTCD-Part4.pdf  . ...

Question:  Caltrans publishes traffic count data that is organized by Route number and post mile.  The database sometimes includes counts on either side of a cross street, labeled as “Back” and “Ahead”.  The Ahead data for one posting should match the Back data for the next one, but sometimes they don’t.  What number should be used when they don’t match? 

Answer:  Caltrans traffic data is available on their website at http://www.dot.ca.gov/hq/traffops/saferesr/trafdata/2000al...

Question:  For left turn signal heads, we usually install it on the mast arm and the far side 1-b pole.  The MUTCD requires a 40 degree viewing angle from the left turn lane.  There are situations that the far side left turn signal head is outside the 40 degree angle zone due to the width of the street.  I know Caltrans doesn’t like to put the 1-b on the median too.  We required to have at least two signal heads for each moment.  So, what’s your opinion for the second left turn signal hea...

Question:  Do slower moving cars need to keep right?

Answer:  Section 21654 of the California Vehicle Code says:  (a) Notwithstanding the prima facie speed limits, any vehicle proceeding upon a highway at a speed less than the normal speed of traffic moving in the same direction at such time shall be driven in the right-hand lane for traffic or as close as practicable to the right-hand edge or curb

The word “Notwithstanding” means that even if a driver is moving 70 mph in a posted 70...

Question:  In a recent signal design, I needed the mast arm signal raised a bit higher for clearance and suggested connecting the MAS mount between the yellow and green indications.  A reviewer told me this is not a good idea, and I’m hoping for a more detailed reason why not. 

Answer:  Caltrans Standard Plan ES-4D (http://www.dot.ca.gov/hq/esc/oe/project_plans/highway_plans/stdplans_US-customary-units_06/viewable_pdf/rspes-04d.pdf) shows the MAS mounting but doesn’t really explain how th...

Question:  I’m designing a traffic signal at an intersection with a heavy right turn out of a minor street, plus a very low volume pedestrian crossing that is in conflict with the right turn move.  I’m thinking of having a right turn arrow that will display a red when there are pedestrians, and will show a green when there are no pedestrians.  The controller is a 170 with McCain software.  Here’s a sketch of what I’m wanting to do, how do I make it work? 

Answer:  McCain software h...

Question:   When can I drive in a bicycle lane?

Answer:  A bicycle lane has a 6-inch wide white line on the left side, and often has pavement markings with the work BIKE or BIKE LANE and a arrow showing the proper direction of travel (see photo).  It may also have Bike Lane signage, a white sign with black text. 

According to California Vehicle Code 21209, it is never legal to drive in a bicycle lane except:

(1) To park where parking is permitted.

(...