Executive Summary

This report documents existing and projected future traffic operations within the section of the Highway 417 corridor from Highway 416 to west of Anderson Road, assuming no improvements to the Highway 417 mainline or interchanges, except for the addition of an interchange at Hunt Club Road by 2021. A brief summary of the study methodology, conclusions and recommendations is presented below. More detailed information is provided in the report and appendices.

Data Collection

Existing traffic volumes and operating conditions within the Study Area were established using 2000 and 2001 counts provided by MTO and TSH, respectively. The City of Ottawa provided ramp terminal intersection turning movement counts (completed between 1999 and 2002), as well as: existing traffic signal timing plans, intersection configuration drawings, transit route and schedule data; and a complete listing of all Highway 417 mainline, ramp and ramp terminal intersection collisions reported from 1998 to 2001. This data was supplemented by on-site reviews completed in August 2001 and August 2002, as well as digital base plans, mapping, aerial photos and discussions with MTO and City of Ottawa staff.

Travel Demand Forecasting

The TRANS EMME/2 travel demand forecasting model of the National Capital Region was used to project future travel demands on Highway 417 and the surrounding road system. The version of the model used for this report is the same version used by the City of Ottawa in preparing its 2003 Transportation Master Plan, and is based on the City's most current projections of future land use, road network improvements, travel modes, etc. The travel demand forecasts used in this Traffic Operations Study are therefore consistent with the current City of Ottawa Official Plan and Transportation Master Plan (TMP).

The model was used to generate p.m. peak hour auto vehicle and transit person travel demands for the 2001 base year and the 2021 horizon year. A total of seven 2021 scenarios were modelled, including "do nothing", probable improvements to the City road network, added capacity on Highway 417 and potential new freeway facilities (Outer Transportation Corridor and inter-provincial bridges).

TSH completed the initial analysis of future traffic operations in October, 2002. At the time of the initial analysis, the revisions to the TRANS model as part of the 2003 TMP study had not been completed. The initial analysis was therefore based on the model of the day, which included assumptions related to recommended network, transit mode split and trip origins and destinations for the horizon year from the 1997 Ottawa TMP. Adjustments were made to the travel demands in the model to account for changes in forecast population and employment as documented the 2002 Ottawa Official Plan update.

With the completion of the 2003 TMP and the related modifications to the demand forecasting process, model inputs and outputs, the analysis was revisited to ensure the consistency of the 2003 TMP and the Highway 417 Preliminary Design Study. Some of the changes in the modelling approach generated higher travel demand on Highway 417, while others resulted in reductions. The following changes in the modelling process resulted in increased auto demand predictions:

• Change in modelling process;
• Use of 1996 travel survey instead of 1986 survey;
• Adjustments to work trips to account for increased labour force participation between 1995 and 2021;
• Adjustments to account for commercial activity; and
• Higher community to community trip making in the 2003 TMP.

The change in the overall transit mode share target from 20% in the 1997 TMP to 30% in the 2003 TMP produced a decrease in the predicted auto demand.

The net effect of these changes was a reduction in overall auto trips on the National Capital Region road network compared to the earlier models but a small increase in projected auto travel demand on Highway 417 due to a larger proportion of long-distance peak hour trips.

Traffic Volume Projections

Traffic volume growth factors derived from the TRANS model results were applied to the 2001 traffic volumes to estimate 2021 p.m. peak hour traffic volumes for every Highway 417 mainline link, ramp and ramp terminal intersection in the Study Area. 2011 traffic volume projections were produced by interpolating between the 2001 and 2021 volumes in proportion to the city-wide population and employment growth projected in the Ottawa Official Plan. Existing ratios of p.m. peak hour to a.m. peak hour and daily traffic volumes were used to estimate a.m. peak hour volumes and AADT's for each horizon year. Existing and projected future traffic volumes on the Highway 417 mainline are summarized in Figures E-1, E-2 and E-3.

Figure E-1 - Highway 417 Mainline Current and Projected AADT

A Data in table format

Figure E-2 - Highway 417 Mainline Current and Projected a.m. Peak Hour Two-Way Volumes

A Data in table format

Figure E-3 - Highway 417 Mainline Current and Projected p.m. Peak Hour Two-Way Volumes

A Data in table format

INTEGRATION Modelling

The INTEGRATION microscopic simulation model was used to assess the operation of Highway 417 through the Study Area under existing and projected 2011 and 2021 traffic volumes. By simulating the movement of individual vehicles through the Highway 417 corridor, INTEGRATION captures all interactions among the various components of the corridor (on-ramps, off-ramps and freeway mainline sections). The simulation covered a three-hour a.m. peak period and a three-hour p.m. peak period. The 2001 model was calibrated to ensure that it accurately reflected actual peak period operating conditions; the calibrated model was then used with the 2011 and 2021 volume scenarios.

The INTEGRATION model was used to determine the presence and severity of congestion, section by section throughout the Highway 417 corridor. A graphical summary of these results is provided in Appendix F of the report. The model also provided corridor-wide summaries of travel speed and vehicle stops to facilitate assessment of overall corridor performance.

Traffic Operations Analysis

Traffic operations analysis was completed using the methodologies of the 2000 Highway Capacity Manual. These methodologies require that the Highway 417 corridor be broken down into basic freeway segments, weaving sections, merge areas, diverge areas and intersections, with each analyzed separately. The analysis therefore did not reflect all interactions among the various components of the corridor.

The analysis produced an a.m. peak hour and a p.m. peak hour level of service for each freeway section or intersection analyzed under the 2001, 2011 and 2021 volume scenarios. The levels of service (from "A" for free-flow to "F" for very congested) are based on traffic density for freeway sections and delays for intersections. A graphical summary of the freeway mainline analysis results is provided in Appendix F of the report.

Safety Review

A detailed statistical analysis of collision records for the years 1998 through 2001 was completed to identify locations with a higher than expected occurrence of collisions. A probability analysis methodology was used to review a total of 3291 collision records and 259 locations within the Highway 417 Study Area, including all freeway mainline sections, ramps and ramp terminal intersections.

The Study Area was also reviewed in the field from a Human Factors perspective, using an operational evaluation technique known as Positive Guidance. The Positive Guidance review identified traffic operations and highway design conditions related to locations with higher than expected probability of collisions. It also identified safety concerns and potential hazards that were not apparent from the collision history, but found no systemic deficiencies throughout the Study Area.

Conclusions

Travel Demand Forecasting and Traffic Volume Projections:

• Continuing population and employment growth in the City of Ottawa will result in significant growth in travel demands through the Study Area.
  
• With no improvements to Highway 417 through the Study Area, traffic volume growth on Highway 417 will be capacity constrained, resulting in lengthening of peak periods, increases in travel delays, and diversion of long distance trips to the local road network.
  
• If the capacity of Highway 417 through the Study Area is increased, traffic will be attracted from other facilities or from the shoulders of the peak periods until a new equilibrium is reached. No significant change would be expected to the level of service on Highway 417, but an overall improvement in network operations would be achieved.
  
• Major network improvements (inter-provincial bridges, Outer Transportation Corridor) do not significantly change the travel demands on Highway 417 through the Study Area, but they do enhance overall network performance.

INTEGRATION Modelling and Operations Analysis:

• With a few minor exceptions, traffic operations on Highway 417 through the Study Area are projected to deteriorate over the next 20 years if no capacity improvements are implemented.
  
• Existing areas of congestion are projected to expand over time. Substantial growth in congestion is expected in the following locations:
  • Westbound from Walkley Road or Hunt Club Road through the Ottawa Road 174 interchange in the a.m. peak period;
  • Westbound from Ottawa Road 174 into the downtown area in the a.m. peak period;
  • Westbound from the downtown area towards Highway 416 in the p.m. peak period;
  • Eastbound from the Pinecrest Road/Greenbank Road interchange toward the downtown area in the a.m. peak period; and
  • Eastbound from the downtown area to Ottawa Road 174 in the p.m. peak period.
    
• Traffic operations analysis indicates that adding lanes to Highway 417 could restore acceptable operations throughout most of the Study Area. This result does not reflect the traffic demand diversion predicted by the TRANS model, as noted above, and does not consider the technical feasibility or environmental impacts of the widenings.
  
• Many of the ramp terminal intersections (26 in total) throughout the Study Area have existing traffic operations problems or are expected to develop problems in the future, most within 10 years.

Safety Review:

• Statistical analysis of the 1998 through 2001 collision history at 259 locations found 106 locations with collision probability indicators higher than the overall collision probability for the Study Area. Of these, 76 locations were found to have collision probability indicators higher than the overall collision probability for all locations of the same type within the Study Area. These locations have the highest potential for safety improvement. The remaining 30 locations have a lower, but still significant, potential for safety improvements.
  
• The most common factor identified as contributing to the collision history in the locations with higher than expected collision probability was recurring congestion. Restrictive geometric design was also found to be a significant contributing factor, particularly when combined with heavy traffic volumes and recurring congestion. Examples include short acceleration, deceleration and weaving distances, tight interchange curve radii and restricted sight distances.
  
• The positive guidance review found no systemic deficiencies in the existing geometry of the Highway 417 mainline, but identified several locations with violations of motorists' expectations (e.g. left exit, "must exit" lane, exit on tangent to mainline curve, etc.). These locations were all found to be correlated with higher than expected collision probability.
  
• Signage and delineation were found to generally provide an adequate level of positive guidance. Some opportunities were identified for improved signage and/or delineation in areas of motorist expectation violations, restrictive geometric design and complex geometry.

Recommendations

This study has established that there is a need for improvements to the Highway 417 corridor through the primary Study Area to address existing operations and safety issues and to accommodate the expected growth in travel demand anticipated by Ottawa's Transportation Master Plan. The travel demand forecasting completed as part of this study indicates that construction of (or improvements to) alternative facilities will not significantly reduce the expected increase in travel demand on Highway 417. Accordingly, the following improvements should be considered:

• Mainline Widening -- The travel demand forecasting indicates that providing additional mainline and auxiliary lanes will not significantly reduce congestion on Highway 417 in the long term, but will provide relief to the City road network surrounding the Highway 417 corridor. Maximizing the available capacity on Highway 417 will encourage through traffic to remain on the highway, reducing traffic on local streets.
  
• Geometric Improvements -- In areas where the existing geometric design does not meet current standards, improvements can be expected to decrease the probability of collisions and facilitate smoother traffic flow. Removing violations of motorists' expectations should also be a priority, as these are correlated with higher than expected collision probabilities and can also disrupt smooth traffic flow.
  
• Intersection Improvements -- Improvements to increase the capacity of critical movements should be considered at each intersection. Operational improvements to reduce queue lengths should be considered where future operating conditions indicate a potential for queue spill-back onto the Highway 417 mainline.
  
• Positive Guidance Improvements -- Signing, pavement marking, delineation and the overall "message" conveyed to motorists by the roadway and surrounding environment should be considered as part of the improvements recommended above.
  
• Congestion Management -- Recurring congestion will remain in the Highway 417 corridor, even with the implementation of significant improvements. Measures to manage congestion should be considered as part of the design of improvements in order to minimize its effects on traffic operations and safety.

These recommendations are based only on the outcomes of the travel demand forecasting, INTEGRATION modelling, traffic operations analysis and safety review documented in this report. They do not consider technical feasibility, environmental impacts, property impacts or costs.

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Contents | Summary | Introduction | Data Collection | Demand Forecasting | Traffic Volumes
INTEGRATION Modelling | Operations Analysis | Safety Review | Conclusions