TRAFFIC CONTENT

The Traffic Services Division is responsible for maintaining traffic signals, traffic control signage, pavement markings, and City-owned street lights. Traffic Service employees are cross-trained and on-call 24-hours a day/seven days a week to repair or replace damaged or missing traffic control devices.

If you have a traffic services related question or concern or wish to report a faulty signal or traffic sign, please email your request using this email link "Email Us". You may also call the above-message telephone number.

Smile…You’re On Intersection Cameras…

The City of Lewiston Traffic Services Division has installed video cameras for the north and south traffic on 17th Street at 16th Avenue. The cameras are part of “video detection” used to improve traffic operations on area streets. So what will these cameras do?

The City of Lewiston is using them to replace in-pavement inductive loops for signal control. Today inductive loops help detect where and how many cars sit at a signal so the signal can adjust its timing to best serve the most vehicles. Inductive in-pavement loops have reliability problems from failure due to weather, pavement maintenance or utility cuts, giving around five years average service life. They also have trouble detecting vehicles that don’t have the “right” inductive signature, such as tandem trucks or motorcycles.

Nervous about privacy? Some people worry that video detection cameras can identify individuals or objects inside vehicles. However, these cameras are selected for durability and economy, not for high resolution. Also, unlike close-range security cameras, traffic cameras are set high to view the entire intersection and avoid looking into headlights, sunlight or street light reflections off vehicle glass. In short, they are good enough to see where a vehicle is located, but not good enough to see inside a vehicle.

Video detection provides more accurate traffic control at less overall cost. Each camera is set up to view individual lanes and “see” when backups occur in each lane of each intersection approach (called zones). Each camera can monitor as many as 24 zones, so only a few are needed even at very large intersections.

6 signals in the downtown area have preset timing intervals and do not change with the traffic volume.

Remaining signals are traffic actuated from 6' x 6' wire loops embedded in the pavement and are known as traffic detection loops. These loops detect vehicles as they approach the traffic signal and send information to a control cabinet located on a corner near the intersection. The traffic control cabinet then assigns most of the available green time to the heaviest traffic movements. Traffic signals on 21st Street, Thain Grade, and Thain Road are in a coordinated system; the goal of which is to safely move the greatest number of vehicles through the system with the fewest number of stops.

Why

do you have to wait a long time for some signals to change? In the traffic control box, priority is programmed for the main arterial, or the street with the majority of traffic. This means that vehicles traveling on side streets entering a street like 21st have to wait longer for a signal to change.

Some signalized intersections also have emergency vehicle preemption, meaning the emergency vehicle will have a preprogrammed green light priority. The purpose is to allow the emergency vehicle to pass through the intersection as quickly and as safely as possible.

Cities across Idaho are installing energy-saving LED (light-emitting diode) traffic signal lights. LED traffic signals are long-lasting, energy-efficient lights that can be easily installed in the existing signal head structure. While producing highly visible light, LEDs consume 80 to 90 percent less energy than incandescent signals. LED traffic and pedestrian signals generally use 9 to 25 watts, compared to the 75 to 150 watts used by an incandescent signal. Because traffic signals operate 24 hours a day, 365 days a year, the opportunity for savings is huge. In addition to saving energy, LED signals also can reduce relamping cycles of maintenance. This is because LEDs generally last five to seven years, compared to just one year for an incandescent light signal.

The City has installed 367 LED energy saving red lamps in traffic signals. The green and "Don't Walk" indications will be replaced as funding allows. To date, 49 amber, 208 green, and 218 "Don't Walk" have been replaced.

Idaho Highway Districts are beginning to use a new type of traffic signal to improve traffic flow at major intersections. The new signals, affectionately termed "dog house" signals, display five lights instead of the traditional red, yellow, and green. The dog house signal is placed to the left of a standard three-light signal. An example of this signal can be seen at the intersection of 5th Street and Bryden Avenue and Nez Perce Grade and Thain Grade as well as others.

The purpose of the dog house signal is to allow more vehicles to make a left-hand turn when it is safe to do so. When a vehicle approaches a dog house signal:

The City's 7,761 traffic signs are tracked on a computerized database and include stop, speed limits, warning, street names, and various others. Traffic Services is responsible for keeping sight obstructions trimmed back from traffic signage.

To request a new sign, call Shawn J. Stubbers, PE, at 746-3671, ext. 275 or email to sstubbers@cityoflewiston.org.

There are 2,400 street lights in the City. 2,000 are owned and maintained by Avista Utilities. The other 400 are owned and maintained by the City. In 1985, the Mercury Vapor type street lights were all replaced with a more energy efficient High Pressure Sodium street light. To report a street light that is out, please call Avista Utilities at 208-798-1472.

You can request a new street light by calling Shawn J. Stubbers, PE, at 746-3671, ext. 275 or email sstubbers@cityoflewiston.org.

Traffic Service's coordinates, set-up, and take down traffic control for events such as temporary signage for accidents and other special events, parades, permitted special events, and winter storm events.

The City spends $36,150 annually on traffic paint and reflective glass beads for pavement marking. In areas where maximum durability is needed, such as where school crosswalks are located on high volume roads, a melt down plastic material is used.

The City's two two-man paint crews start their season in May and finish around October when inclement weather begins. Each crew consists of one full-time and one seasonal employee. One crew works a day shift from 7:00 a.m. to 3:30 p.m. repainting centerlines and edge lines. The second crew works nights from midnight to 7:30 a.m. repainting crosswalks, arrows, curbs, and stop bars. Pavement marking includes:

For more traffic related information, you can visit the US Dept. of Transportation, Federal Highway Administration at www.fhwa.dot.gov.