City of San Marcos Traffic Management Center The Traffic Management Center (TMC) at San Marco City Hall is a critical part of an advanced traffic management system that manages traffic flow in the city. The TMC remotely controls 84 of the 130 traffic signals in San Marcos. It also provides real‐time video feeds from 30 traffic cameras strategically located at the city’s busiest intersections. Traffic engineers staffing the TMC can check signal operations, adjust signal synchronization timings and monitor traffic progression throughout the city. The TMC opened in 2003 and was made possible through Congestion Management and Air Quality Improvement Program (CMAQ) funding. Since then, the city has used federal and state funding to improve the center. Recent improvements include installing additional traffic cameras, upgrading traffic controllers, deploying an adaptive traffic control system on San Marcos Boulevard, and establishing a fiber optic communication network to interconnect many of the city’s signals and traffic cameras. The City will continue to aggressively seek federal and state grants to improve traffic operations throughout the City.
Vehicle Detection n Vehicle d detection sysstems sense the presencce of vehiclees and send ssignals to the traffic controlleer asking for green light ttime. Two tyypes of detection techno ologies are u used in San Marcos: inductive loo op and video o.
Inductive e Loop Dete ection Inductive Loop Detecction is a trad ditional vehiicle detectio on technologgy that has eexisted for m more than 30 0 years. Loop p detectorss are thin wires in the ro oadway paveement that recognizee vehicles wh hen they drive on top off a loop. Thee advantages of loop detection include reliability, accuracyy and weather iindependence. Disadvan ntages includ de high failu ure rate, infleexibility and disruption o of traffic flow w during installatio on and maintenance.
Video D Detection Video Detection is aa modern vehicle detection technolo ogy that hass become on ne of the prim mary alternaatives to loop detectorrs at intersections. It dettects vehiclees through a camera placed on th he signal maast arm and aa video processo or at the signal cabinet. It “recognizes” cars by analyzin ng real‐time changes in tthe pixels in the backgro ound image. TThe advantagges of video detection are it is easy to install an nd maintain with no intrrusion to roaadway pavement, more reaadily adaptaable to changging conditio ons at intersecttions (e.g., laane reassign nment and teemporary lane closure ffor work zon ne activities). The disadvvantage is that it is adverssely affected d by camera motion, daily changes in n light leveel, seasonal changes in tthe sun's possition and gllare problem ms. Fogs and rain also afffect its working capabilitties, resultingg in a numbeer of false deetections. Th he City is wo orking closely w with video de etection prod duct vendorrs to improvee performan nces of video o detection system. TThese activitties include u upgrading syystem softw ware, fine‐tun ning system configuratio on and deteection zones set up, and obtaining m more technical training to o staff.
Signal O Operationss Actuated Timing Actuated d timing adju usts the amo ount of green n time for eaach signal cyycle. The tim ming is calculated through vvehicle dete ection system ms installed at the interssection. Wheen a vehicle is detected,, a message goes to the signal contrroller requessting more ggreen time to o move carss through thee his continuess until the syystem no lon nger senses vehicles or u until the sign nal reaches iits signal. Th maximum m green time e cap set by the controlller. This typee of system is used to m minimize the interrupttions to majo or‐street traaffic flow at llocations wh here traffic vvolumes flucctuate duringg the day. A majority of the City’s signals are operating under actuated co ontrol. nated Timing Coordin Coordin nated timing signal contrrol implements synchron nized timing tto a series off signals alon ng a corridorr to allow grroups of vehiccles to move through thee traffic sign nals without significaant delays. C Coordinated timing is inttended to improvee travel timee, reducing sstops and miinimizing delay on heavyy traffic flow w corridors d during peak p periods. It iss always cchallenging tto implemen nt a perfectly timed plan n that meeets competing demand in different directions of traffic m movement. TTypically, peaak direction of traffic flow receivess the highesst priority in a coordinatted timing networkk. The amoun nt of green ttime allocateed to each movemeent dependss on the trafffic demand iin the netwo ork level. Traaffic engineeers use advan nced compu uter program ms to ne the best ccoordinated timing planss for the corrridor. Currently, signals along major determin streets su uch as Las Po osas Road, R Rancho Santa Fe Road, SSan Elijo Roaad are coordinated durin ng peak perriods.
Adaptive Traffic Co ontrol Adaptivee Traffic Conttrol Systemss (ATCS) adju ust in real tim me. Signal timing is baseed on the current traffic co onditions, de emand and system capaccity. Real‐tim me traffic volume, occup pancy and sp peed data are collected fro om numerou us system deetectors placced along th he corridor aand transmittted to the ceentral traffic control systtem. The ATC CS utilizes th hese data to calculate op ptimal trafficc timing paarameters su uch as cycle lengths (tim me necessaryy to serve alll directions o of traffic), sp plits (allocated time to eaach movemeent), and offssets (amoun nt of time to drive from o one intersecction mize delays aand reduce tthe number of stops. The City deplo oyed a pilot A ATCS to the neext) to minim
system along San Marcos Boulevard to adapt corridor timing to respond to events such as freeway incidents, fluctuation in traffic flow, school traffic, and/or special events. Traffic Signal Operations Q & A
Q: A:
How many traffic signals are there in the City of San Marcos?
Q: A:
Why do traffic lights take so long to change?
Q:
Why does a signal serve green time to a side street when no vehicles are present?
130 signals citywide, 84 of which are “on the network” and are able to be remotely controlled from the City’s Traffic Management Center.
Signal timing cycle lengths in the City of San Marcos usually fall between 45 and 140 seconds. The timing for each signal is determined based on traffic volume and traffic patterns in each particular area. Cycle lengths are typically longer at intersections along major corridors (e.g. San Marcos Boulevard) in order to accommodate higher volumes of traffic, to serve the greater number of separate traffic movements during the timing sequence and to accommodate much longer pedestrian crossing times. Overall, these longer cycle lengths provide more efficiency since they can move more vehicles through an intersection in a given amount of time. However, increasing cycle lengths may also cause longer waiting time on minor streets.
A:
For most traffic signals in San Marcos, the signal rests on the green light for the major street in order to serve the greater volume and switches to the side street upon demand (when vehicles are detected). If the signal is sequencing to the side street for no apparent reason, it could be because of one of these situations:
Q. A.
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The vehicle detectors are not operating correctly. Vehicle detectors sometimes malfunction.
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The traffic signal has detected a vehicle that has subsequently made a right turn at the intersection.
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The traffic signal is within a coordinated corridor.
When traveling on some streets, why do I always seem to get a red light?
There are many elements that go into traffic phasing and signal operations. A few of the elements include pedestrian activity, the time of day, day of the week, construction activity, traffic incidents, and even the weather. When driving at or near speed limits between traffic
signals along the major coordinated corridors in San Marcos, there should not be major delays if the traffic signal system is functioning normal and roadway is not completely saturated.
Q: A:
Why can't we get a left‐turn arrow at a signalized intersection?
Although left‐turn arrows benefit turning traffic, they also increase waiting times for other traffic and pedestrians using the intersection. For this reason, certain criteria are used to ensure they are installed at locations where they do not adversely affect other movements. The criteria used when evaluating the need for a left‐turn arrow signal are: •
how well the movement is operating without a left‐turn signal.
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how much the left turn signal will increase the waiting times to other traffic movements at the intersection
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the accident history for the movement
Q: Why isn't there enough green time at a signal to get the traffic through at some approaches? A: The amount of green time programmed for each movement at a signal varies by traffic demand. When there are shorter green lights it is often because there is more traffic than the signal can handle, and the signal is over its capacity. In these situations, the Traffic Engineering Division attempts to time the signals to equalize delays for conflicting movements. In general, increasing green time for one movement requires decreasing the amount of green time for another movement.
Q. Who determines the amount of time for pedestrian crossing? A. Pedestrian times can seem to be too long and usually create delay for the coordinated movement along an arterial roadway. Unfortunately, this is one area the City does not have the ability to change. The City is obligated to follow the State and Federal guidelines for pedestrian timing of signals. The current timing has been found to be a bit long for most healthy adults, but the pedestrian timing also addresses the needs of others, such as, senior citizens and those with disabilities.
Q: Is it really necessary for me to push a button to activate the pedestrian signal? Can’t I just wait for the light to change? A: Buttons are available to pedestrians, because the traffic signal is timed for cars, not for people on foot. If you don’t activate the pedestrian signal by pushing the button, the traffic light may not allow you enough time to safely cross the street. You only need to push the button once for it to be activated.
Q: A:
How do I report a problem with a traffic signal?
Call the City of San Marcos Public Works at 760‐752‐7550. The staff fills out a form which is forwarded to City’s traffic signal technicians who will verify the report and take necessary actions to rectify the problem. When you call, please give us specific information about the location of the signal, direction of travel, weather and time of day you encountered the problem so we can make the repair as quickly as possible.
Have Additional Questions? Contact Omar Dayani (Tel: 760‐744‐1050, ext 3255; Email: ODayani@san‐marcos.net) or Linna Zhang (Tel: 760‐744‐1050, ext 3219; Email: LZhang@san‐marcos.net) for traffic signal operation related questions. Contact Michael Rafael (Tel: 760‐744‐1050, ext 3274; Email: MRafael@san‐marcos.net) or Omar Dayani for traffic safety related questions.
General Traffic Safety Related Q & A Q: We have motorists speeding on our City streets. How can you help us with this problem? A: Speeding is a behavioral issue that comes out of the demand of our increasingly busy lives. The City of San Marcos receives several hundred complaints each year from concerned citizens regarding speeding, especially on residential streets. To respond to speeding concerns, following measures proven to be helpful: •
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The County of San Diego Sheriff’s Department provides speed enforcement on City streets. However, limited resources prevent them from targeting all areas at all times. Please call the Sheriff’s station at 760‐510‐5200 for speed enforcement in your area. The City uses radar feedback speed trailers to assist with traffic calming efforts. These trailers display the speed of approaching vehicles and are effective tools for increasing driver awareness. These radar feedback speed trailers have been proven to be effective in reducing vehicular speeds in many areas. Please call the Traffic Engineering Section at 760‐744‐1050 ext. 3274 or email mrafael@san‐ marcos.net to reserve a radar speed trailer in your neighborhood. The trailers
are on a first‐come, first‐serve basis and are typically placed along the roadway for one week.
Q: A:
Can the City lower the speed limit on a particular roadway?
When traffic problems occur, concerned citizens frequently ask “why can’t we lower the speed limit”. There are widely held misconceptions that speed limit signs will reduce the speed, reduce accidents, and increase safety. Most drivers drive at a speed that they feel comfortable, regardless of the posted speed limit. Before and after studies have shown that, there are no significant changes in average vehicle speeds following the posting of speed limit signs. Furthermore, research has found no direct relationship between posted speed limits and accident frequency. State law (California Vehicle Code) requires local agencies to establish speed limits based on Engineering and Traffic Surveys (ETS). The City conducts speed surveys throughout the City and speed limits are set accordingly once every five to seven years. These surveys include an analysis of roadway conditions, accident collisions, land use, and a sampling of the prevailing speed of traffic. The prevailing speed is determined by measuring the existing speeds of motorists during free flow (off‐peak periods). The State of California has established the 85th percentile speed as the prudent speed for a roadway, which is the speed at which 85% of the motorists are traveling at or below. For this reason, state law requires speed limits be posted at the nearest 5 mph increment to the 85th percentile in order for law enforcement to radar enforce the roadway. Speed limits set above the prevailing speed are generally considered unreasonable and unsafe. Speed limits set below the prevailing speed do not provide an orderly movement of traffic. Traffic flowing at uniform speed results in increased safety and fewer accidents. Drivers are less impatient, pass less often, and tailgate less, which reduces both head‐on and rear‐end collisions. The posting of the appropriate speed limit simplifies enforcement measures by the Sheriff’s Department. Excessive speeders are easily spotted, safe drivers are not penalized, and traffic officers are not asked to enforce and defend unrealistic and arbitrary speed limits.
Q: A:
Can you install a stop sign to reduce speeding?
Each year, the City receives numerous requests to install stop signs as way to reduce speeding and accidents. Stop signs are typically installed to regulate traffic flow and to assign right‐of‐way at an intersection, not to control speeding.
The City of San Marcos uses the California Manual of Traffic Control Devices (CA‐MUTCD) criteria for installing a stop sign at intersections. Our traffic engineering section will determine
if a stop sign is warranted for a specific location based on an engineering study. A stop sign is not a cure‐all for traffic problems. The indiscriminate use of the stop signs at random locations will develop disrespect in the mind of motorists and result in increase in violation and accident potential throughout the City. Also, the use of unwarranted stop signs to control speeds usually result in higher peak speeds between stop signs and higher accident rates. The City does not typically install stop signs at T‐intersections in residential areas. The right‐of‐ way at T‐intersections is covered under the California Vehicle Code, which requires that motorists on the T‐leg yield to motorists on the through roadway. Stop signs are generally used on the minor leg of a T‐intersection if there is significant traffic volume on the through street.
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Can the City install speed humps or speed cushions on my street?
Q:
Can I get “Children at Play” signs installed on my street?
The City of San Marcos does not recommend the use of speed humps, bumps, or speed cushions in the City. Although used primarily as a traffic‐calming device in other cities, speed humps create a neighborhood noise nuisance and delay emergency response times (Fire, Sheriff, paramedics, etc.) on City streets. Some motorists would speed up between the humps to make up for lost time and others would divert to other streets to avoid the humps, transferring the speeding issue from one area to another. The residents living near speed humps typically complain about the noise nuisance and debris dropped from trucks driving over the speed bumps.
A: Children at Play signs and similar signs are not recognized by the State of California or by the Federal Highway Administration as an official traffic control device and therefore, are not installed by the City on public streets. These type of signs send the wrong message to children and parents by encouraging them to play within the street. The City discourages this behavior, as a pedestrian’s interaction with vehicles could result in potential accidents. These signs create a false belief for children by letting them assume they are safer when these signs are installed. The City provides many neighborhood parks where children can play safely with proper supervision.
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Can I request a crosswalk?
A crosswalk is the portion of a roadway at an intersection that is the extension of the sidewalk and curb lines of the intersecting streets, or is any other portion of a roadway marked as a pedestrian crossing by painted lines. Crosswalks are either “marked or unmarked”, as defined by the Califronia Vehicle Code (CVC). A marked crosswalk is delineated by white or yellow painted markings placed on the pavement. In general, the City does not paint or mark crosswalks at locations where traffic is not controlled by stop signs or traffic signals.
Studies indicate that marked crosswalks may give pedestrians a false sense of security. Pedestrians often step off the curb into the crosswalk expecting the approaching drivers to stop. The crosswalk markings, however, may not always be readily apparent to drivers and are sometimes unable to stop or fail to stop, causing an accident. Although drivers must yield the right‐of‐way to pedestrians at crosswalks, two painted lines do not provide protection against an incoming vehicle.
Q: A:
Can the City paint the curb red in front of fire hydrants?
The subject of parking next to fire hydrants is addressed in the California Vehicle Code (CVC) Section 22514, which states, “No person shall stop, park, or leave standing any vehicle within 15 feet of a fire hydrant”.
Since the CVC already states that it is illegal to park within 15 feet of a fire hydrant, whether or not there are signs or red curb, the City is not required to designate the area in front of a fire hydrant as a no‐stopping zone. Typically, the City does not install signage or paint red curbs for situations that are already addressed in the CVC. If there is a pattern of repeated violations by motorists parking next to a particular fire hydrant, it can be addressed by increased enforcement by the Sheriff’s Department or the City’s Code Enforcement section.
Q: I cannot see the oncoming traffic at a particular intersection or when exiting my driveway. Can you help? A: Traffic Engineering staff usually conducts a field study in the area adjacent to a driveway or at a particular intersection when there is a sight visibility concern, to determine whether or not restriction of parking adjacent to the driveway or near the intersection is recommended. In addition to the study, staff checks accident records to determine if the collision data supports the need to remove any parking spaces. In all cases, motorists should exercise caution when leaving private property or a side street. The CVC Code Section 21804(a) states that motorists entering a highway from public or private property shall yield the right‐of‐way to all traffic on the highway and shall continue to do so until he or she can proceed with reasonable safety. Motorists could move slowly forward pass the stop bar or toward the edge line of the parking lane to gain more visibility to safely exit the driveway or side street.
Q: A:
What is the Traffic Safety Commission?
The Traffic Safety Commission is an advisory group of citizens appointed by the City Council. This is a committee that meets the first Wednesday of every month at 6:00 PM to discuss traffic issues raised by residents or City staff. The meetings are held to determine the
best course of action to improve a traffic‐related issue. These meetings are open to the public, and everyone is encouraged to attend.
Q: A:
Can I request a street light on my street?
Q: A:
How do I submit a traffic‐related request?
Most of the existing street lights were installed based on the City of San Marcos Street Lighting Design Standards and Caltrans standards for roadway lighting. Streetlights on residential streets are typically located at intersections, cul‐de‐sacs, and along vertical or horizontal curves to provide safety lighting at critical roadway locations. For general street light maintenance issues, please contact Public Works at (760) 752‐7550.
All requests for traffic studies are to be submitted in writing using a “Traffic Study Request” form available at the Engineering Counter, or from the Traffic Engineering webpage. If you like a request form mailed to you, call the Engineering Division at (760) 744‐1050 ext. 3229 to request one. Please mail it to the City Hall address (Attn: Traffic Engineering) or email the form to mrafael@san‐marcos.net. When a written request is received, we will notify the requestor and provide an estimate of the time required to evaluate the request. Most of the requests require data collection, which may take a few weeks to complete and evaluate. Requests are evaluated on a first‐come, first‐served basis. Requests may be brought up to the Traffic Safety Commission for review and approval. Like nearly all cities in the California, the City of San Marcos uses the California Manual on Uniform Traffic Control Devices (CAMUTCD) to evaluate the need for traffic control devices for particular situations. The CAMUTCD contains guidelines or “warrants” for each type of traffic control device. The purpose of these warrants is to ensure consistency in the implementation of traffic control devices to conform to motorists’ expectations and achieve uniform driving behavior throughout the State of California.