Traffic Control

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Street Signs

The City of Ankeny has over 15,000 traffic and street signs, so a lot of attention is given to their fabrication, installation and maintenance. The City has its own sign shop, which fabricates signs for use on City streets, and makes specialty signs for other City departments. The signs are designed and installed according to the national standards.

Report concerns regarding street signs

Stop signs that are missing or damaged are considered urgent and require a quick resolution. If you see an existing stop sign that is missing or damaged, please call us immediately at (515) 965-6481 during business hours or if after hours please call Polk County Dispatch at (515) 286-3333.

Concerns regarding other street signs can be reported in four ways:
  1. E-mail us with a description and location of the sign and any other pertinent information. Please include your name and phone number.
  2. Call the City of Ankeny Maintenance Facility between the hours of 7:00 a.m. to 4:00 p.m., Monday through Friday at (515) 965-6481.
  3. For after hours or emergencies, call Polk County Dispatch at (515) 286-3333.
  4. You may also make a report online.

Sign Requests

One sign that the City receives numerous requests for each year is the "Children at Play" sign. This sign is intended to be used in areas where large number of children are present, such as a regional park or playground. It has been the City's policy not to erect this sign in residential neighborhoods, because it suggests that children will be safe to play in the street. There are children in many of the neighborhoods throughout the City and to place a sign at the end of each street would desensitize the traveling public to these signs.

Traffic Signals

The Public Works - Operations Division currently maintains traffic signals at 59 intersections within the City. The traffic signals are designed, constructed, operated and maintained to allow for safe and efficient movement of vehicles and pedestrians through heavily traveled or hazardous locations. The traffic signal phases or cycles are changed by overhead cameras or detection loops in the street pavement. These cameras or loops sense the presence of vehicles and notify the traffic signal that a vehicle is at a specific location at the intersection. Most of the traffic signals along the major streets have timings that change depending upon the time of day or the day of the week in order to provide optimal traffic flow through the intersections.

Report Concerns Regarding Traffic Signals

Occasionally electrical component failure, power fluctuations and damaged or burned-out bulbs will prevent a traffic signal from working correctly. Common concerns include the red, yellow, or green lamps are out or the traffic signals are flashing. Knowing all of the specific details such as the time of day, conditions, traffic, etc. really helps us to trouble-shoot your concern.

You can report a traffic signal that is not working correctly in three ways:
  1. Call the City of Ankeny Maintenance Facility between the hours of 7:00 a.m. to 4:00 p.m., Monday through Friday at (515) 965-6481.
  2. For after hours or emergencies, call Polk County Dispatch at (515) 286-3333.
  3. You may also make a report online.

The city has found that most reports for a traffic signal not working correctly can be traced to faulty vehicle detection (i.e. the controller is not "seeing" your car). The loops in the pavement can get worn and fail, or the cameras can get misaligned by strong winds, or they miss vehicles due to precipitation, glare, etc. These issues are usually easily remedied by our signal technicians.

Other reports we generally receive focus on the timing of the traffic signals, and these are more difficult to resolve. If the issue is related to a red light staying on too long, or if a certain direction does not get enough green time, the cause may be inherent to the timing plan for the traffic signal. While our staff can make some adjustments to the red and green times that may help address these timing issues, the amount of cross traffic can limit what we can do. This is especially true at peak commute times when traffic from all directions at an intersection can be heavy.

Signal Improvements, Operations and Maintenance

From time to time, Public Works Department - Operations Division will receive requests to install new traffic signals at an intersection. To see if a traffic signal is needed, we count vehicles over a 48-hour period and check the traffic volumes against a set of standard warrants. When enough of the warrants are met, the intersection is deemed warranted for traffic signals. If the intersection is on a state highway within Ankeny, the Iowa DOT must approve of the traffic signal installation as well. At that point, a traffic signal installation project could be included in our capital improvements program, to establish the future funding for the traffic signals. A new set of traffic signals generally cost at least $250,000.

The growth of our City has facilitated the expansion of our traffic signal system. In recent history, the City has added at least one traffic signal per year. In addition n to new signals, the City has recently upgraded all of our signals by:

  • Changing out the standard signal bulbs with LED bulbs. The LED bulbs provide a different, somewhat brighter light for each of the red, yellow, and green indications. The LED bulbs also are more energy efficient (i.e. they use a fraction of the electricity of the older style bulbs) and last much longer.
  • Changing out the pedestrian signal heads form the old standard "walk/don't walk" indications to the new "countdown" indications. This is a safety improvement for all of our signals, as the new "countdown" style provides specific information to pedestrians so they know how long they have to cross the street.

Each traffic signal is operated by an independent controller located next to the intersection. The controller changes the phases for traffic approaching from each direction using an internal timer and actual detections of the number of cars approaching from each direction. Each signal controller has a timing plan for the number of seconds each phase will stay on, given the number of cars waiting on the given approach.

Each signal controller "sees" the approaching cars in each direction by either cameras or induction loops. About 2/3 of our traffic signals have cameras mounted on the mast arms or in other locations such as on a nearby light pole. The cameras are the modern way to detect approaching vehicles, and we have found them to be generally reliable and accurate. Please note that our cameras are for vehicle detection only. The City of Ankeny does not use cameras for traffic enforcement.

On the remaining traffic signals, the vehicle detection is by induction loops, which are wires buried in the street pavement at the intersection. With the loops, a car is detected when it drives over the loop and interrupts a magnetic field within the loop. The loop detectors are an older style of detection than the cameras, and are generally not as reliable. As our budget allows, we are removing the loops and replacing them with cameras.

The traffic signals at our busier intersections are equipped with battery backups, which allow a signal to operate for at least 1-2 hours without power. After that, the signal would go into an all-way flash mode. The traffic signals on our busier corridors such as Highway 69 and First Street are equipped with emergency vehicle preemption equipment. These traffic signals are set up to automatically turn green for fire trucks and ambulances that are traveling to an emergency call. As soon as the emergency vehicle passes, the traffic signal returns to normal operation.

Street Lights

The City leases a majority of the street lights from MidAmerican Energy. The City does own and maintain a number of street lights, including some within the Ankeny Uptown area. The Engineering Division maintains an inventory of existing street lights and monitors the installation of new street lights on all public and private projects. Street lights are installed at intersections and intermediate locations to provide safe and comfortable lighting levels at night. The lighting levels are periodically reviewed to determine whether light pollution and glare can be reduced.

If you have a street light out in your neighborhood please call MidAmerican Energy at 1-888-427-5632 or use their online problem reporting form.