Traffic Signals
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The Traffic Signal Viewer Map highlights various features of each of the City’s 260 signalized intersections.
Overview
Intersections can have a number of characteristics to improve safety and traffic flow. Traffic signals that are properly designed will have one or more of the following advantages:
- They provide for the orderly movement of traffic.
- They increase the traffic-handling capacity of the intersection.
- They reduce the frequency and severity of crashes, especially right-angle collisions.
- They can be coordinated to provide for continuous or nearly continuous movement of traffic at a definite speed along a given route under favorable conditions.
- They are used to interrupt heavy traffic at intervals to permit other traffic, vehicular or pedestrian, to cross
Improper or unjustified traffic signals can result in one or more of the following disadvantages:
- Excessive delay
- Excessive disobedience of the signal indications
- Neighborhood cut-through traffic as drivers attempt to avoid the traffic control signals
- Can result in increases in rear-end collisions
An engineering study of traffic conditions, pedestrian characteristics, and physical characteristics of the location needs to be performed to determine if installation of a traffic control signal is justified at a location. The City of Alexandria performs traffic signal warrant studies and follows the factors contained in the Manual on Uniform Traffic Control Devices (MUTCD) to determine when to install a traffic signal.
Pedestrian signals
Pedestrian signals tell pedestrians when they should cross the street. The City has been actively working to install pedestrian signals at all of the 260 signalized intersections, and approximately 95% of intersections now have pedestrian signals.
Many of the City’s pedestrian signals are push button activate to ensure pedestrians have adequate crossing time but in locations where signals are on a timed cycle, the pedestrian signals are automatic (much of Old Town).
The graphic below provides guidance on how to use pedestrian signals and what the icons mean:
Accessible Pedestrian Signals
Accessible pedestrian signals help people with disabilities cross the street. These signals provide audible and vibro-tactile notification to pedestrians. All new traffic signals should be installed with accessible pedestrian signals. The City is actively working to retrofitted older signals with accessible signals at high priority locations, upon request and as budget permits.
Leading Pedestrian Intervals (LPIs)
LPIs help pedestrians establish their presence in a crosswalk by giving them a head start over vehicular traffic at a signalized intersection. This is an important enhancement that allows pedestrians to initiate their crossing early and get far enough into the crosswalk that they will be more visible to drivers. As part of the Vision Zero efforts, the City has greatly increased the number of intersections with LPIs over the past few years and currently has LPIs at 36 intersections Citywide. There are a number of factors to consider when installing LPIs, such as the presence of No Turn on Red Signs and accessible pedestrian signals as well as pedestrian volumes and documented safety concerns.
HAWK Signals
A High-Intensity Activated crossWalK, or HAWK, is a is a special type of traffic signal used to warn and control vehicular traffic at a pedestrian crosswalk to assist pedestrians in crossing a street. HAWKs are typically used at midblock crossings where there are both high pedestrian and vehicular volumes and often multiple lanes of traffic. The City conducts engineering analysis to ensure that criteria from the MUTCD is met to justify a HAWK signal. The City currently has four HAWK signals with one coming soon on Braddock Road near Minnie Howard.
The graphic below provides guidance on how to use a HAWK signals.
Contact
To report a problem with a traffic or pedestrian signal, please use Alex311 Customer Service Portal and search " traffic signal." To reach the Traffic Operations Division, call 703.746.4006.