7. Safety Review

A safety review of the Highway 417 mainline and interchanges was conducted throughout the primary Study Area, comprising a collision history analysis and positive guidance review. The methodology and results of the safety analysis are summarized in the following sections; additional details are provided in Appendix H.

7.1 Collision History Analysis

7.1.1 Methodology

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 within the primary Study Area. A probability analysis methodology was used for this analysis. The methodology produces a "probability score" for each highway mainline section, merge/diverge/weaving area, ramp and ramp terminal intersection that can be compared to the statistically "expected" probability of collision occurrence for all similar locations, and for the corridor as a whole, to identify collision-prone locations. The methodology adjusts for factors such as section type, exposure (traffic volume) and collision severity to allow for valid comparisons among different locations throughout the Study Area. Detailed descriptions of the selection and application of this methodology are provided in Appendix H.

The data used for the analysis was obtained from the City of Ottawa collision database. After a review of collision data available from the City and MTO, the City's data was selected for use because it provides the following advantages:

• Differentiates between mainline roadway collisions and diverge/merge collisions at off/on ramp junctions (this differentiation is considered to be accurate, since all police reports are reviewed at the time of data entry, and the categorization of the collisions is done by considering the collision description, vehicles involved and the vehicle manoeuvres);
• Ensures that all collisions at ramp terminal intersections are included, regardless of whether the collision report identified the location as a provincial or municipal roadway;
• Directly differentiates between "mainline roadway sections within interchanges" and "mainline roadway sections between interchanges" in the database, instead of relying on LHRS and offset location identification;
• Provides complete data through 2001. The MTO database was complete only through 2000.

7.1.2 Results

The collision history analysis reviewed a total of 3291 collision records representing four years of data. Table 7.1 provides a breakdown of collision occurrence by location type and severity. Collision rates for Highway 417 throughout the Study Area range from 0.2 to 1.6 collisions per million vehicle-kilometres of travel. This is comparable to the provincial average for freeways, which is 0.6 collisions per million vehicle-kilometres of travel.

The probability analysis methodology identified the collision probability indicator for each of the seven location types and for the Study Area as a whole. These values are summarized in Table 7.2. A total of 106 locations out of the 259 locations analyzed were found to have collision probability indicators higher than the overall collision probability for the Study Area. These locations are considered to have a poorer than expected safety performance, indicating a significant potential for safety improvement. The remaining 153 locations have a safety performance above the level expected for the corridor as a whole, indicating a relative low potential for safety improvement.

Table 7.1 - Highway 417 Collision Counts by Severity and Area Type, 1998-2001

Area Type	Severity
	Fatal	Injury	PDO*	Total
Diverge	1	95	379	475
Merge	0	43	115	58
Ramp Intersection	0	153	372	525
Off-Ramp	0	33	117	150
On-Ramp	0	47	152	199
Mainline between interchanges	1	220	929	1150
Mainline within interchanges	5	154	475	634
Total	7	745	2539	3291

*PDO - Property Damage Only

Table 7.2 - Expected Collision Probability Indicators by Location Type

Location Type	Collision Probability Indicator
Mainline Links	2.982
Mainline Links within Interchange	4.221
Merge Areas	0.264
Diverge Areas	1.210
On-Ramps	2.736
Off-Ramps	2.066
Ramp Terminal Intersections	2.753
Overall	1.860

Field review and collision analysis was focussed on the locations with significant potential for safety improvement. These locations were identified as being in either a Primary or Secondary category on the basis of their collision probability scores, as follows:

• Primary -- collision probability indicator higher than the overall indicator for the Study Area and higher than the collision probability indicator for the location type; and
• Secondary -- collision probability indicator higher than the overall indicator for the Study Area, but lower than the collision probability indicator for the location type. (If the location type indicator is lower than the overall Study Area indicator, no locations of that type can be classified as Secondary.)

A total of 76 locations were identified in the Primary category, having the greatest potential for safety performance improvements. A further 30 locations were identified in the Secondary category, having a lower, but still significant, potential for safety performance improvements. Table 7.3 summarizes these locations. Further details on all of the locations of higher than expected collision probability are provided in Appendix H.

Table 7.3 - Locations with Higher Than Expected Collision Probability (by location type, in descending order of probability)

Mainline Sections Between Interchanges, Primary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
WB between Richmond Rd. and Hwy 416 Interchanges	0	2	9	10.541	Congestion, tail of queue
WB between Walkley Rd. and Innes Rd. Interchanges	1	1	6	9.137	Curvilinear section, ascending slight grade Gravel shoulders to left and right Transition from illuminated to non-illuminated section Transition to rural environment Open terrain likely prone to blowing snow Signed as deer crossing -night danger Minimal delineation on outside of curves Operating speeds 110 km/h by pace Speed, tight curve radii, weather effects possible contributorsAdditional delineation may benefit
WB between Lyon St. and Bronson Ave. Interchange	0	1	13	7.271	Congestion
EB between Nicholas St. and Metcalfe St. Interchanges	0	9	43	6.245	Congestion
EB between O'Connor St. and Metcalfe St. Interchange	0	7	23	6.197	Congestion
WB between Parkdale Ave. Interchange and Island Park Drive	0	12	47	5.991	Congestion
WB between Vanier Parkway and Nicholas St. Interchanges	0	7	55	4.785	Weather effects resulted in cluster of collision events in this vicinity on one day (freezing rain)
EB between Nicholas St. and Vanier Parkway Interchanges	0	8	50	4.612	Congestion
EB between Woodroffe Ave. and Maitland Ave. Interchanges	0	15	60	4.537	Congestion
EB between Anderson Rd. and Walkley Rd. Interchanges	0	7	22	4.167	Speed, weather effectsAlignment is curvilinear, non-illuminated.Would benefit from additional delineation
EB between Carling Ave./Kirkwood Ave. and Parkdale Ave. Interchanges	0	16	70	4.070	Congestion
EB between Innes Rd. and Ottawa 174 Interchanges	0	1	10	3.992	Weaving, speed
EB between Pinecrest Rd./Greenbank Rd. and Woodroffe Ave. Interchanges	0	15	44	3.863	Congestion
EB between Vanier Parkway and St. Laurent Blvd. Interchanges	0	11	27	3.747	Congestion
EB between Maitland Ave. and Carling Ave. Interchanges	0	12	44	3.500	Congestion
EB between Rochester St. and Bronson Ave. Interchanges	0	8	27	3.461	Congestion
WB between Island Park Drive and Carling Ave. Interchanges	0	5	23	3.379	Congestion
EB between Hwy 416 and Richmond Rd. Interchanges	0	3	2	3.361	Congestion
WB between Nicholas St. and Metcalfe St. Interchanges	0	7	20	3.299	Congestion
EB between St. Laurent Blvd. Interchange and Cyrville Rd.	0	3	8	3.177	Congestion

Mainline Sections Between Interchanges, Secondary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
WB between Metcalfe St. Interchange and O'Connor Ave.	0	5	10	2.975	Congestion
WB between Cyrville Rd. and St. Laurent Blvd. Interchange	0	6	15	2.904	Congestion
WB between Pinecrest Rd./Greenbank Rd. and Richmond Rd. Interchanges	0	2	15	2.788	Congestion
WB between Rochester St. and Parkdale Ave. Interchange	0	9	39	2.647	Congestion
EB between Innes Rd. and Walkley Rd. Interchanges	0	3	9	2.576	Congestion
WB between Maitland Rd. and Woodroffe Rd. Interchanges	0	5	33	2.531	Congestion
EB between Parkdale Ave. Interchange and Rochester St.	0	8	47	2.366	Congestion
WB between Carling Ave. and Maitland Ave. Interchanges	0	5	46	2.002	Congestion
WB between Bronson Ave. Interchange and Rochester St.	0	2	17	1.921	Congestion
WB between O'Connor St. and Lyon St.	0	4	24	1.916	Congestion

Mainline Sections Within Interchanges, Primary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
EB within Ottawa Rd. 174 Interchange	2	5	10	38.245	Curve to the right after major split.Tight radiiTraffic released from queue/congestion.Ramp merging on right
EB within Innes Rd. Interchange	1	2	1	20.732	Curvilinear section on an ascending gradeTransition from illuminated to non-illuminated sectionEnvironmental conditions may play a roleSpeed may be a factor
WB within St. Laurent Blvd. Interchange	1	15	55	15.803	Major weaving areaRecurring congestion - tail of queueSpeed differential between merging and through vehicles in shoulders of the peak
WB within Vanier Parkway Interchange	1	9	21	8.262	Left then right curve through the interchangeRamp 26 merges on inside of curveInfluence of diverge to Ramp 61 - ramp is on tangent to approaching roadwaySight distance in Lane 1 constrained by median elementsCongestion
WB within Bronson Ave. Interchange	0	17	40	6.956	Recurring congestionVery short weaving area, high levels of activityShort ramps result in speed differential between merging and through traffic
EB within Parkdale Ave. Interchange	0	11	38	5.372	Highly congested during peak periodsVertical crests and sags my impact sight distance
WB within Parkdale Ave. Interchange	0	13	29	4.832	Highly congested during peak periodsVertical crests and sags my impact sight distance

Mainline Sections Within Interchanges, Secondary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
EB within Maitland Ave. Interchange	0	4	14	3.962	CongestionInfluence of traffic slowing for "B" loop exit
EB within Richmond Rd. Interchange	0	2	16	3.832	CongestionWeaving - Richmond on-rampsHigh-speed traffic coming from 416 NorthCongestion, tail-of-queue
WB within Carling Ave. Interchange	0	9	39	3.780	Weaving, congestion
WB within Woodroffe Ave. Interchange	0	3	35	3.009	Weaving, congestion
EB within Nicholas St. Interchange	0	9	19	3.005	Weaving, congestion
EB within Woodroffe Ave. Interchange	0	7	20	2.932	Weaving, congestion
EB within Walkley Rd. Interchange	0	2	7	2.730	Tight horizontal curve through intersectionTraffic merging from rampsLack of delineation on outside of curve
WB within Hwy 416 Interchange	0	8	25	2.494	Congestion, speed
WB within Walkley Rd. Interchange	0	6	8	2.431	Tight horizontal curve through intersectionTraffic merging from rampsLack of delineation on outside of curve
EB within Vanier Parkway Interchange	0	7	17	2.381	Curvilinear horizontal alignmentCongestion and speed
EB within St. Laurent Blvd. Interchange	0	5	10	2.213	Congestion, weaving to left exit for Ottawa 174 split
WB within Pinecrest Rd./Greenbank Rd. Interchange	0	3	15	1.979	Weaving, congestion

Diverge Areas, Primary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
Woodroffe Ave. W-N/S Ramp EB Hwy 417	1	2	4	7.255	Observed queuing on ramp back to diverge
Walkley Rd. 417W-E/W Ramp and EB Hwy 417	0	1	12	2.662	Ramp exits on inside of curve - potential for oversteerDamage to delineation on outside of curve to the leftSuspect run-off-the-road-type collisions involving adjacent mainlineSpeed may be a factor
Nicholas St. E-E/W/N Ramp and WB Hwy 417	0	7	36	2.185	Ramp alignment is tangent to approaching roadway as mainline curves away to the leftSigning infers Lane 3 is a "Must Exit" - may be resulting in driver confusion
Hwy 416 E-S Ramp and WB Hwy 417	0	4	18	2.108	Left exit potential for violation of expectationCongestion westbound throughout area in the p.m.Suspect drivers may be using ramp for queue jumping before re-entering WB 417 mainline
Carling Ave. E-W/N/S and WB Hwy 417	0	8	20	2.002	Recurring congestion, high proportion of weaving activity
Nicholas St. W-E/W/N Ramp and EB Hwy 417	0	5	30	1.991	Queuing back from STOP on Lees StreetLittle advance warning of split on ramp - traffic slows just beyond gore to accommodate
St. Laurent Blvd. W-N/S Ramp and EB Hwy 417	0	6	16	1.905	Double lane exitLane 4 is an auxiliary lane from Vanier ParkwayHeavy weaving area.Ramp queues up in peak period

On-Ramps, Primary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
Carling Ave. S-E Ramp (Ramp 65)	0	13	41	86.228	Short merge, weaving, congestion
Richmond Rd. S-W Ramp	0	1	10	78.112	Tight inner loop, grade change
Pinecrest Rd./Greenbank Rd. N-E Ramp	0	2	6	13.359	Tight inner loop, grade change
Pinecrest Rd./Greenbank Rd. S-E Ramp	0	5	16	8.846	Speed, grade change, intersection influences, congestion
Richmond Rd. N-E Ramp	0	2	0	7.364	Tight inner loop, grade change
Walkley Rd. E-W Ramp	0	1	1	6.729	Speed, tight curve midway through ramp
Innes Rd. E-S Ramp	0	1	2	6.421	Tight inner loop, grade change
Nicholas St. N-E Ramp	0	2	8	5.786	Tight inner loop, grade changeLane ends on curve
St. Laurent Blvd. S-E Ramp	0	0	3	5.219	Speed, sight distance, congestion
St. Laurent Blvd. S-W Ramp	0	1	3	4.663	Tight inner loop, grade change, sight distance restriction
Nicholas St. N-W Ramp	0	3	13	4.477	Traffic arrives over crest vertical curve; reduced sight distance to rampSouthbound traffic from Nicholas Street at high speedSharp inner loop on descending gradeLane ends in curve before merge
Hwy 416 S-E Ramp	0	4	4	3.437	Descending gradeLimited delineationAdvisory speed sign not conspicuous, too close to curveSpeed too fast for conditions
St. Laurent Blvd. N-E Ramp	0	1	0	3.387	Tight inner loop, grade change
Metcalfe St. W/S-E Ramp	0	3	7	3.310	Queuing and congestion, configuration
Richmond Rd/Bayshore Dr. S-E Ramp	0	2	2	3.304	Speed, descending grade, limited sight distance, congestion

On-Ramps, Secondary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
Ottawa Rd. 174 E-417E/Aviation Pkwy. N-417E	0	1	4	2.399	Tight inner loop on an ascending grade. Initial merge between Aviation Pkwy. ramp and Ottawa Rd. 174 ramp on an ascending grade.Speeds on Aviation Pkwy. ramp are high - speeds on Ottawa Rd. 174 ramp are significantly lower.Ottawa Rd. 174 ramp right lane terminates over blind crest after right turnBox beam guide rail with turned-down end treatment
Parkdale Ave. N/S-W	0	1	0	2.272	Climbing grade, limited sight distance over crest, congestion
Nicholas St. S-E Ramp	0	1	2	2.082	Configuration, limited sight distance, congestion
Walkley Rd. W-E Ramp	0	0	1	1.861	Speed, configuration of gore area split

Off-Ramps, Primary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
Woodroffe Ave. E-N Ramp	0	2	4	20.191	Confusing configuration with Transit interfaceCongestion
Richmond Rd. E-N/S/W Ramp	0	3	13	10.220	Sharp curve on entryConfusing configuration with Transit interfaceCongestion
St. Laurent Blvd. E-N/S Ramp	0	3	12	9.087	Labelle St. intersection on ramp violates driver expectationsSight distance to intersection limitedCongestion from signalized intersection
Island Park Dr. E-N Ramp	0	2	0	8.392	Tight curve, limited sight distance
Hwy 416 E-S Ramp	0	2	4	6.793	Limited delineation on outside of curveSpeedIcing on structure in curve suspected
Pinecrest Rd./Greenbank Rd. W-N/S/E Ramp	0	5	12	6.007	Lane merges onto off-ramp - violation of expectationCongestion, queuing from complex intersection phasing
Hwy 416 W-S Ramp	0	1	5	5.005	Limited delineation on outside of curveSpeedIcing on structure in curve suspected
Bronson Ave. W-N/S Ramp	0	1	5	4.552	Sharp reverse curves on entry, limited sight distance
Vanier Parkway W-N/S/E Ramp	0	3	2	4.195	Right then left curveBarrier on inside limits sight distanceNo delineation on barrier to the leftQueuing70 km/h advisory speed OK (ball bank)
Nicholas St. W-N/E/W Ramp	0	3	6	3.591	Split after exit provides little advance warningDirectional signing is minimalDowngradeFriction between traffic destined for Lees Avenue and traffic destined to northQueue back from STOP sign
Maitland Ave. W-N/S Ramp	0	0	4	3.276	"B" loop, speed, weather conditions
St. Laurent Blvd. W-N/S Ramp	0	3	4	3.075	Congestion, downgrade, limited sight distance
Carling Ave. W-N/S/E Ramp	0	0	6	3.059	Merge on left after exit, then split to Carling Ave. EastWeaving
Walkley Rd. 417E-E/W Ramp	0	1	3	2.864	Downhill grade, speedEvidence of run-off-the-roadTruck skid marks in gore
Maitland Ave. E-N/S Ramp	0	1	2	2.528	"B" loop, speed, weather conditions

Ramp Terminal Intersections, Primary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
Woodroffe Ave. Interchange, North Ramp Terminal	0	16	49	9.690	Configuration, congestionConsider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information
Nicholas St. W-E/W Ramp at Lees St.	0	8	6	8.693	Sight lines, All-Way STOP ControlSignals not currently justified
Intersection of O'Connor St. and Catherine St.	0	11	30	8.283	Configuration, channelization issuesConsider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information
Hwy 417/Hwy 416 Interchange W/S-N/S Ramp intersection with Holly Acres Rd.	0	8	6	8.167	Weaving area on ramp approach to intersection is shortSpeeds in weave are highConsider amending lane designation, lengthening weave area
Woodroffe Ave. Interchange, South Ramp Terminal	0	13	32	6.704	Consider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information
Pinecrest Rd/Greenbank Rd Interchange, South Ramp Terminal	0	12	23	5.299	Complex intersectionRamp very close to intersectionRight turning traffic from Iris Street
Maitland Ave. Interchange, North Ramp Terminal	0	9	23	4.742	Consider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information
Intersection of E-N/S Ramp and Lemieux, Intersection of St. Laurent and Labelle - North Ramp Terminal	0	7	35	4.674	Eliminate Lemieux St. intersection as a point of potential conflictConsider channelizing, timing, phasing and conspicuity improvements at St. Laurent Blvd.Improve directional signing information
Intersection of Metcalfe St/Isabella St. and S/W-E Ramp	0	7	21	4.658	Consider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information
Bronson Ave. Interchange South Ramp Terminal	0	10	9	3.783	Consider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information
Maitland Ave. Interchange, South Ramp Terminal	0	7	23	3.530	Consider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information
St. Laurent Blvd. Interchange, South Ramp Terminal	0	6	20	3.249	Downgrade, long cycle length, impatience
Pinecrest Rd/Greenbank Rd. Interchange, North Ramp Terminal	0	6	14	3.189	Consider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information

Ramp Terminal Intersections, Secondary

	Collision History (1998-2001)				Field Review Findings
Description	Fatal	Injury	PDO	Probability Indicator	Possible Contributing Factors and Potential Countermeasures
Innes Rd. Interchange West Ramp Terminal	0	5	20	2.703	Improve operations on Innes Road east and west of the ramp terminal
Innes Rd. Interchange East Ramp Terminal	0	8	10	2.682	Improve operations on Innes Road east and west of the ramp terminal
Intersection of O'Connor St., Isabella St. and W-E Ramp	0	3	11	2.341	Consider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information
Parkdale Ave. Interchange North Ramp Terminal	0	2	8	1.919	Consider channelizing, timing, phasing and conspicuity improvementsImprove directional signing information

7.2 Positive Guidance Review

7.2.1 Methodology

The primary Study Area was reviewed from a Human Factors perspective, using an operational performance evaluation technique known as Positive Guidance. The methods and processes applied in this review are consistent with those outlined in Ontario Traffic Manual (OTM) Book 1C -- Positive Guidance Toolkit. For a more complete discussion of the role of Human Factors and Positive Guidance in Road Safety Science, refer to Appendix H of this report, and to OTM Book 1C.

The review was conducted by a road safety specialist during the period August 16-19, 2002. It included drive-through and stationary observations using a vehicle equipped with a precision distance measuring device, a ball-bank indicator (for measuring safe speeds on curves), and all necessary safety equipment. Observations were made during weekday and weekend peak and off-peak periods, as well as during both daylight and night-time conditions. Weather conditions were clear throughout the review.

Maps identifying locations with higher-than-expected collision risk, as well as collision summaries, were available for reference during the photography. A brief summary of overall findings is presented below. Additional detail is provided in Appendix H.

7.2.2 Findings

The positive guidance review included examination of a wide range of characteristics of the roadway, traffic and surrounding environment, including:

• Traffic composition/characteristics;
• Roadway alignment;
• Lane and shoulder widths;
• Pavement condition;
• Pavement markings;
• Delineation;
• Stopping sight distances;
• Manoeuvring distances;
• Environmental issues (e.g., weather);
• Illumination;
• Roadside safety;
• Adjacent land uses;
• Signing;
• Intersection traffic controls; and
• Congestion.

The findings in each of these areas are summarized in Appendix H. Based on the findings of the review, the following conclusions can be drawn:

• There are no systemic deficiencies in the existing geometry of the Highway 417 mainline, when viewed from a human factors perspective, however there are several instances of violations of expectation (e.g. left exits and "must exits"). Where they exist, violations of expectation have been conspicuously identified using traffic control devices. All of these locations of concern were captured as either 'PRIMARY' or 'SECONDARY' locations of higher than expected collision probability.
  
• Site-specific safety concerns regarding the available stopping sight distance through horizontal curves to the left, for drivers in Lane 1 (median barrier limits sight distance through the chord), and on crest vertical curves (stopping sight distance to object on the roadway), identified in the initial stages of the Geometric Review (based on Plan and Profile drawings), were confirmed to exist in the field. These concerns, and their implications, are detailed further in the Existing Conditions Report -- Highway Geometrics.
  
• Drivers on the Highway 417 mainline are provided with an adequate level of positive guidance. Signs, markings, delineation and geometry are all well-integrated and relatively consistent throughout.
  
• Drivers entering Highway 417 from on-ramps within the urban boundary are often challenged to match the operating speed of traffic and merge before their lane either ends or exits. Opportunities to provide more generous acceleration/merge lanes, to minimize the use of auxiliary/"must exit" lanes, and to provide greater preview of the traffic ahead and alongside, should be explored.
  
• Drivers exiting Highway 417 on off-ramps within the urban boundary are often confronted with tight geometry, limited sight distances, and the need to significantly reduce speed to match road geometry and traffic conditions. Additional emphasis on advisory speeds, enhanced delineation, improved sight distance and adequate perception/reaction/manoeuvre time are required.
  
• The geometry and lane arrangement of many of the crossing roadways are complex and demanding on the unfamiliar driver. While significant efforts to communicate these configurations through signs and markings have been made, it may be necessary to consider physical channelization at some locations in order to reduce the frequency and severity of vehicular conflicts.

To address the identified issues, the following actions are recommended:

• Investigate and resolve the stopping sight distance issue with respect to drivers in Lane 1, adjacent to median barrier and anti-glare screen, in left-hand curves on the mainline, and in relation to crest vertical curves;
• Provide additional acceleration/merge time/distance whenever possible in reconfiguring on-ramps, and avoid use of "must exit" lanes where possible;
• Consider the application of oversized advisory speed signs and enhanced delineation on off-ramps;
• Provide additional sight distance whenever possible in reconfiguring off-ramps;
• Provide improved directional signing on complex off-ramps; and
• Upgrade existing barrier end treatments to current standards.

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