Dallas Five Leg Inersectioin

				The CEE for the Dallas Five-Leg Intersection Improvement Project identified natural, cultural, and socioeconomic resources that are present within the project area, and assessed impacts to said resources as a result of construction. No significant impacts to natural, cultural, and socioeconomic resources will occur within the project area. Only minor temporary impacts may occur to vegetation in the area, as well as temporary minor Erosion and Sedimentation along the Toby Creek, during construction.
				The project CEE was approved and environmental clearance was obtained on March 30, 2011. A link the Approved CEE is provided in the Links section of this website.
				Alternatives Analysis
				As part of the preliminary design process, various alternatives were evaluated based on input from PennDOT, the project team, and the public to best achieve the project purpose.
				The project team and PennDOT initially developed three (3) conceptual alternatives. Option 1: Circular single-lane roundabout Option 2: Conventional signalized intersection Option 3: Two circular single-lane roundabouts After receiving feedback at the first Citizen Advisory Committee (CAC) meeting, two additional alternatives were developed: Option 1A: Oval single-lane roundabout Option 4: Large oval single-lane roundabout that included Machell Avenue All five (5) alternatives were displayed at the first public meeting. Consensus was reached between the CAC, public officials, and the public for Option 1 and Option 1A. Both options were presented at a second public meeting. A feasibility study was prepared and after careful review, PennDOT selected Option 1A for an oval roundabout with a single circulating travel lane.
				Build Option 1
				Build Option 1A
				Build Option 2
				Build Option 3
				Build Option 4 (Initiated by CAC Members)
				Preferred Design Alternativeand Traffic Simulation
				Results in improved traffic flow, particularly during the peak periods. Slight oval shape was selected based on public input as having a more desirable and aesthetic appeal. Based on the design, the traffic flow is very similar to the circular roundabout option. Addresses concerns at the closely spaced intersection with Machell Avenue Exiting motorists at Machell Avenue will be restricted to right-out only. Motorists wishing to turn left onto Memorial Highway (SR 0415) must turn right and travel through the roundabout to make a U-turn. The intersection design is pedestrian-friendly. Sidewalks and crosswalks are provided throughout. Crossing widths are great reduced to a single travel lane at all locations with pedestrian refuges provided on each approach with the roundabout’s splitter islands, enabling pedestrians to cross one direction of traffic at a time. Dallas Intersection Traffic Simulation (VISSIM software) Description: Traffic simulation (using VISSIM software) was completed to illustrate the future 2030 design year weekday afternoon peak hour operating conditions for the Dallas five-leg roundabout. Several video clips of the simulation are linked below. In order to prepare the traffic simulation, existing traffic data was collected during the weekday afternoon peak period. This traffic data was then projected into the future to the year 2030, so the traffic simulation illustrates more traffic than under current conditions. Additionally, due to the improved pedestrian connectivity, the number of pedestrians illustrated in the simulation is also much greater than observed today. The Dallas five-leg intersection roundabout design elements, as well as Machell Avenue and adjacent accesses, were incorporated into the traffic simulation. The existing bus stop along PA Route 415 will be relocated immediately to the west of the roundabout, stopping prior to the crosswalk, and is also illustrated in the traffic simulation. Roundabout intersection operations Video Clip 1 Video Clip 2 Machell Avenue U-Turn Pedestrians Bus stop operations
				Preferred Alternative – Build Option 1A
				Roundabouts: Fact and Fiction
				Traffic Circle/Rotary versus Modern Roundabout
				Modern roundabouts are not the same as traffic circles/rotaries. Many traffic circles/rotaries were constructed in New Jersey, and are being replaced by modern roundabouts. The Wilkes-Barre Public Square is a relatively local example of a traffic circle. Below is a table, comparing the characteristics of traffic circles/rotaries to those of a modern roundabout.
	TRAFFIC CIRCLE/ROTARY MODERN ROUNDABOUT Larger Diameter = Higher Speeds Smaller Diameter = Lower Speeds Right-of-way given to entering traffic Right-of-way given to circulating traffic Entries often include traffic signals (due to large size and higher speeds) Vehicles yield upon entry Entries do not provide splitter islands for deflection (which slow vehicles down) or for pedestrian refuge Splitter islands provided at entries to slow vehicles and allow pedestrians a refuge to cross one direction of traffic at a time Pedestrian crossings within the circulatory roadway to destinations within the center of the circle No pedestrian crossings to the central island
				Wilkes-Barre Public Square Traffic Circle – NOT a Roundabout
				Modern Roundabouts in the United States
				The modern roundabout is a common form of traffic control throughout the world. The United States is still behind other nations in constructing modern roundabouts, but there are currently over 2,200 in operation. Roundabouts are being constructed at a rate of about 150 to 250 per year nationwide. There are a number of roundabouts in operation in Pennsylvania and surrounding states, as follows:
				90+ in Maryland 70+ in New York 30+ in Virginia 17 in Pennsylvania 8 in Delaware
				Recent Comparable Pennsylvania Roundabout Project
	Location: Rochester, Pennsylvania in Beaver County Intersection: Adams Street (S.R. 0068) and Brighton Avenue/Rhode Island Avenue (S.R. 0018) Setting: Gateway to Rochester’s Central Business District; Adjacent to the Beaver County Transit Authority HUB; Intersection carries approximately 22,000 vehicles per day (existing) Project Info: Single-lane, five-leg oval roundabout Completed in 2011 After Study Results: Reduction in traffic backups on Rhode Island Avenue by 95%; Reduction in cut through traffic by 35% on West Washington Street Link: Beaver County Transit Authority – Rochester Roundabout Webpage
				Roundabout Videos & Dallas Intersection Traffic Simulation
				Federal Highway Administration
				Modern Roundabouts – A Safer Choice
				Center for Roundabout Research and Training – Kansas State University
				You Tube
				British Columbia – Emergency Vehicles instructions McMahon Associates Channel Dallas Intersection Traffic Simulation (VISSIM software) Description: Traffic simulation (using VISSIM software) was completed to illustrate the future 2030 design year weekday afternoon peak hour operating conditions for the Dallas five-leg roundabout. Several video clips of the simulation are linked below. In order to prepare the traffic simulation, existing traffic data was collected during the weekday afternoon peak period. This traffic data was then projected into the future to the year 2030, so the traffic simulation illustrates more traffic than under current conditions. Additionally, due to the improved pedestrian connectivity, the number of pedestrians illustrated in the simulation is also much greater than observed today. The Dallas five-leg intersection roundabout design elements, as well as Machell Avenue and adjacent accesses, were incorporated into the traffic simulation. The existing bus stop along PA Route 415 will be relocated immediately to the west of the roundabout, stopping prior to the crosswalk, and is also illustrated in the traffic simulation. Roundabout intersection operations Video Clip 1 Video Clip 2 Machell Avenue U-Turn Pedestrians Bus Stop Operations Schwenksville, PA Roundabout Video Quakertown, PA Roundabout Video Mount Rainier, MD Roundabout Video Beaver County Transit Authority – Rochester, PA Roundabout
				Rochester PA Roundabout Simulation
				Roundabout Safety
				Overall Roundabout Safety Principles:
				Design forces slower vehicular speeds Results in a significant reduction in conflict points Results in fewer and less severe crashes
				Roundabout safety statistics for the United States based on the Insurance Institute of Highway Safety (IIHS):
				90% reduction in fatal crashes 70% reduction in injury crashes 70% reduction in pedestrian crashes 40% reduction in all crashes Elderly drivers Statistically have difficulty making left-turn maneuvers Roundabout eliminates left-turns Roundabout forces lower speeds
				Current Dallas Five-Leg Intersection Crash Summary
				Approximately 70% of the crashes involve left-turns or rear-ends, which are typical at signalized intersections Approximately 50% of the crashes involve injuries
				Conflict Points at the Dallas Five-Leg Intersection
				Conflict Point – A point at which drivers cross, merge or diverge. This term is used to define crash potential.
				Under the current signalized intersection configuration, there are 25 vehicle-to-vehicle conflict points (shown below as red dots) Under the proposed roundabout configuration, there are 10 vehicle-to-vehicle conflict points, which are confined to the entrance and exit points (shown below as red dots)
				Pedestrian Accommodations
				Roundabout creates a more “walkable” community
				Splitter islands on each leg improve pedestrian crossing safety Shorter overall crossing distances (see illustrations below) Crossing of one direction of traffic at a time ADA-compliant sidewalks and ramps will be provided New sidewalks will connect to the existing sidewalk network on all sides of the intersection
				Right-of-Way
				15 total properties impacted Seven (7) properties requiring permanent right-of-way acquisition Thirteen (13) properties including temporary construction easements No properties to be taken in total, except the abandoned gas station property on the north side of PA Route 415 between Lake Street and Church Street Acquisitions underway
				Project Design and Construction Schedule
				Preliminary Engineering: 2008 through 2011 Final Engineering: Ongoing Final engineering and right-of-way acquisitions are currently underway. Award of the project construction contract is set for 2014. Commencement of utility relocations in 2015 Completion of Upper Demunds Intersection Improvement Project and improvements at the intersection of PA Route 415/PA Route 309 Commencement of Dallas Five-Leg Intersection construction in 2016
				Construction – Traffic Control, Staging, and Duration
				Goal:
				To provide EFFICIENT, QUALITY, SAFE construction, minimizing impacts while maintaining traffic operations and access to businesses.