2014
Condition Diagram
Ephrem Woldetsadik @02666435 9/30/2014
Condition Diagram Objectives:
The objective of this study is to develop condition diagram for 4 intersections. Introduction/Background:
A site survey should be conducted to record relevant geometric and traffic control data. These data include: number of lanes, lane widths, lane configurations, presence of tu rn bays, length of turn bays, length of pedestrian crosswalks, and intersection widths for all approach legs. An effective method for recording this information is with a condition diagram. A condition diagram shows existing intersection layout including such features as roadway geometry, channelization, grades, number and width of travel lanes, lane use, speed limit, parking restrictions, driveways, bus stops and distance restrictions (1). The location of an y land uses including schools, parks, playground and other sig nificant pedestrian generating facilities should be indicated on the diagram. Other information that can have an impact on signal operations include: approach grades, presence of on-street parking, presence of loading zones, presence of transit stops, dips in approach profile near the intersection, and intersection skew angle (2). Many of these factors may have an impact on the capacity of one or more movements at the intersection; they may also influence intersection safety (2). Th e condition diagram should provide engineers with details of field conditions and help study the need for changes to existing traffic control devices and to do so a field evaluation should be conducted (2). Scope:
There was a study of various intersections, accurate measurements, and detailed locations of traffic control systems to create the condition diagram. F our intersection were chosen for the site survey in Washington D.C.; 10 street NW & U Street NW (Figures 1 and 2), Sherman Ave NW & Barry Pl NW (Figures 3 and 4), Sherman Ave NW & Girard Street NW (Figures 5 and 6), and Georgia Ave NW & Gresham Pl NW (Figures 7 and 8).
Figure 1: Aerial view of 10 th street at U street NW
Figure 3: Aerial view of Sherman Ave NW at Barry Pl NW
Figure 5: Aerial View of Sherman Ave NW at Girard Street NW
Figure 2: Street view of 10 th street at U street NW
Figure 4: Street view Aerial view of Sherman Ave NW at Barry Pl NW
Figure 6: Street view of Sherman Ave NW at Girard Street NW
s Figure 7: Aerial View of Georgia Ave NW at Gresham Pl NW
Figure 8: Street view Aerial View of Georgia Ave NW at Gresham Pl NW
Methodology and Data Collection:
The measurements at all 4 intersections were taken by a measuring wheel in feet. The measurements included widths of travel lanes, bus stop lanes, driveways, on-street parking space, and sidewalks. To collect the measurements, a sketch of the top view for each intersection was drawn before going to each site on September 21, 2014. Since a drawing was available for all sites, it was simple to write all the measurements from the top view for each intersection. After gathering all the measurements and features for each intersection, AutoCAD was used to illustrate the intersections with the measurements and features. AutoCAD is a 2 -D and 3-D computer-aided drafting software application used in architecture, construction and manufacturing to assist in the preparation of blueprints and other engineering plans. All intersection drawings with a legend are attached with the report. Analysis of Result:
See attachment. Conclusion/ Recommendations:
A condition diagram provides importation information when remodeling an d improving intersections. A recommendation would be to make sure all intersections for each state are up to date and are available for engineers to look up on the web.
References 1. DeBenedictis, John. "Traffic Signal Operation Design Guidelines." Cityofboston. Boston
Department of Transportation, 4 Sept. 2004. Web. 28 Sept. 2014. . 2. "Traffic Signal Timing Manual." Office of Operation. U.S. Department of Transportation, 1 Jan. 2004. Web. 28 Sept. 2014. . 3.
Condition Diagrams Information, Dr. Stephen Arhin; https://blackboard.howard.edu/webapps/blackboard/content/listContent.jsp?course_id=_1037 101_1&content_id=_1530770_1&mode=reset Accessed Sept. 28, 2014.
