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Transportation Questions

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Speed Humps/Lumps

How do I get speed humps/lumps on my street?

A Speed Lump petition must be signed by at least 10 residents from separate households. Visit the Speed Lump Program webpage to learn about how a street qualifies and download a petition.

Street Lights

My streetlight is out. What should I do?

Please dial 311 or use the 311 app and be prepared with the address that the light is closest to. Please notice if there is a single light out or if several are out. Our mission is to replace burned out streetlights within 30 days of receiving the call except on weekends. If the problem is greater than just a burned out bulb, a technician will be assigned to repair the light within four weeks.

Why are some streetlights white and some orange looking?

Different styles of lights work at different color temperatures. The white lights use a Mercury Vapor or Metal Halite lamp, while the orange lights use a High Pressure Sodium lamp.

Why do I see some streetlights going on and off?

This indicates a high-pressure sodium lamp (orange light) is nearing the end of its life. Contact the Street Lighting Shop for prompt repair.

Why are some streetlights painted and others are not?

Older streetlights rust and need to be painted. The City's new standards include aluminum flutes or galvanized poles that don't require painting.

What can be done when a streetlight is a nuisance because of its location and brightness?

Please dial 311 for more information, and about a possible solution.

Traffic Signals

What happens when a traffic signal malfunctions?

The traffic signal controller is monitored by a device called the Malfunction Management Unit (MMU). This device monitors specific problems that would result in an unsafe condition. For example, if the controller tries to display green lights in conflicting directions at the same time, the MMU would place the intersection into flashing mode. The MMU monitors many other things as well, such as the power voltage and the length of time that a yellow light is displayed.

Are traffic signals coordinated from one to another?

In most cases, traffic signals are typically coordinated from one to the next. It is easy to see such coordination on downtown streets. 16th street is a good example of this coordination. Other streets are also coordinated, even though it may not be as obvious to the observer.

Many factors affect coordination: the spacing of signals, the time needed for pedestrians to cross, light rail trains, and volume of cars in all directions have an impact on when a light can turn green for you. Our downtown grid is mostly one-way streets that are evenly spaced, which makes coordination easier, but the majority of the City's streets that are outside of downtown are two-way and the signals are not evenly spaced. This causes vehicle arrival times to the signal from both directions to vary. There are still a few of the City's corridors that are not coordinated and the department is working to close the gap in the system.

What do pedestrian crossing indications mean at a signal?
  • Walking person means you can legally enter the street to cross.
  • Flashing red hand means do not start to cross, but if you are already in the street, you may legally finish crossing.
  • Solid red hand means do not enter the street as cross traffic has the right-of-way.
How do traffic signals detect cars?

Many of the City's traffic signals have a way to detect vehicles. Some locations have a loop of wire placed in the roadway that can determine when a vehicle is present. The installation of loops in the pavement can cause the pavement to fail and can be difficult to maintain.

To minimize the pavement problem, the City has been using video detection. The video detection system works by providing an image to a small computer that can detect a change in the image and determine the presence of a vehicle.

Video detection can sometimes be compromised by interactions with the environment other than vehicles. Fog, dust, shadows, trees, headlights and the reflection of the sun on the asphalt can all have adverse effects on the accuracy of detection. The City continually tests new technologies that come to market to find the best solutions.

Why are there cameras at some intersections?

Cameras can serve many purposes at an intersection. Several years ago, the City made the move to reduce the amount of hardware installed in pavement. To achieve this, the City has deployed video detection camera systems that use a machine vision processor and have the ability to detect vehicles in the camera's field of view. This system sends the signal to the traffic signal controller that a vehicle is there and needs service.

CCTV cameras are also located at some intersections. These cameras are used to provide information to the City’s Traffic Operation Center that operators use to verify traffic conditions and traffic signal timing. The Department of Public Works does not record the video.

Do trains or light rail affect the signals?

Yes and no. There are many locations that detect light rail and heavy rail trains through an intersection. To improve safety, many of these locations have gate arms that stop traffic across the tracks when trains are present. The traffic signals must provide a clearance interval for any vehicles that may be on the tracks. This is done by providing a green light in the direction needed to clear the tracks. This can hold up traffic at the intersection but is necessary to help prevent accidents with trains.

On several streets in the downtown area, the light rail trains share lanes with vehicular traffic. Typically, some advantage is given to the light rail to maintain efficiency sometimes interrupting traffic signal timing.

For rail crossing safety information please go to Operation Life Saver.

Can Emergency vehicles cause the signal to change?

Yes, but not at all intersections. Emergency vehicles carry a device that provides a signal to the traffic signal controller. As an emergency vehicle approaches the intersection with emergency lights on, the signal controller will finish serving the current pedestrian and vehicle phase, and then provide a green light for the oncoming emergency vehicle. This helps to reduce emergency vehicle response times and increases intersection safety.

What does a traffic signal cost?

The cost to install a traffic signal varies depending on the size of an intersection and if roadway modifications are needed. Typically, the cost can range between $300,000 and $400,000.