Prince Edward Island, Canada
From IHSDMDownload
User Information
Organization/Agency: Delphi-MRC (McCormick Rankin Corporation)
Basic Project Information
Project Name/Description: Prince Edward Island
Nature of the Project/Study: Road safety and operational review
Project Location: Route 1 from North Tryon to Cornwall, Prince Edward Island (PEI), Canada
Highway Length: Approximately 33 km
Functional Classification: Arterial
Design Speed:
Original design drawings were not available for this section of road. Based on the 90 km/hr posted speed, a design speed of 100 km/hr was assumed. There were localized sections where the posted speed limit was reduced. Design speed for these sections was assumed to be 10 km/hr above the posted speed.
Posted Speed: Typically 90 km/hr, with localized reductions to 60, 70, and 80 km/hr.
Terrain Type: Mostly level to rolling
Application of IHSDM
IHSDM Module(s) used:
• Policy Review
• Crash Prediction
• Design Consistency
• Traffic Analysis
Purpose of using IHSDM on this project:
This project was conducted for the Prince Edward Island (PEI) Department of Transportation and Public Works (DTPW). It was essentially a feasibility study to determine the level of effort required to collect data and develop a model for a considerable length of arterial road and to determine the value of the various analysis outputs of this tool to decision makers at DTPW.
Route 1 forms part of the Trans Canada Highway in Prince Edward Island. The roadway is a two-way-two-lane rural highway with numerous passing lanes. As development grows on the island, traffic volumes at intersections located within the passing lanes have resulted in road safety and operational concerns. The purpose of this study was to model the existing corridor using IHSDM to provide a baseline to which the impact of proposed passing lane closures and modifications could be compared.
As part of this study, the Crash Prediction Module was calibrated to reflect PEI conditions. The Policy Review Module was also modified to reflect geometric requirements from the Transportation Association of Canada’s Geometric Design Guide for Canadian Roads (TAC).
Stage(s) of the project development process in which IHSDM was applied (e.g., planning, preliminary design, final design, etc.):
Planning
How IHSDM results were used to make design decisions:
The road was checked against TAC guidelines to identify deficiencies and policy concerns, particularly relating to lane width and widening, shoulder width and configuration, curve radius, minimum and maximum grades, and vertical curve k-values. Stopping sight distance deficiencies were identified, and locations where lateral sightlines beyond the shoulder must be checked and maintained were highlighted. This may help DTPW make decisions on setting regulatory speed limits which reflect the geometric restrictions of the roadway. The locations of designated passing zones were also compared to available passing sight distance.
The Design Consistency Module was run to outline locations of significant speed differential between tangents and curves; locations where warning devices and forgiving roadside could be considered. It also points out areas where the geometry suggests operating speeds are likely to remain high even though the speed limit and assumed design speed are reduced.
The calibrated Crash Prediction Module was used to estimate the expected crash frequency on this section of roadway; with and without the inclusion of historical crash records. This number was checked against the historical number of crashes and forms a baseline comparison to which potential improvements can analyzed in terms of benefit-cost.
The Traffic Analysis Module was run to determine the operating Level of Service under existing conditions. This forms a basis of comparison when considering removing, shortening, or reconfiguring passing lanes as a safety improvement and facilitates the operational component of trade-off analysis. The graphs produced by the software also help to point out locations where new climbing lanes could be considered to improve the capacity of the roadway or to reduce long queues and speed differentials between cars and trucks.
