REZONING APPLICATION 2023-04 – 294 AND 296 ELTHAM ROAD AND 242 HELMCKEN ROAD (Attachment A)

3.0 PROJECTED TRAFFIC VOLUMES

3.1 Site Generated Trips

To estimate the number of vehicle trips expected to be generated by a development, trip generation rates are applied based on the proposed land uses and intensity. The number of trips that would be generated by a proposed development would usually be estimated based on the rates published in Trip Generation Manual, 11th Edition by the Institute of Transportation Engineers (ITE).

The trip generation rates along with the proposed land uses and the corresponding ITE land use codes are presented in Table 2. The proposed development’s generated trips are presented in Table 3.

Table 2: Trip Generation Rates ITE 11th Edition Trip Generation Manual

Table 3: Projected Site-Generated Peak-Hour and Daily Traffic Volumes

3.1.1 Pass-by Trips

Pass-by trips are not new trips, but they are the trips that are attracted from the traffic passing the site on adjacent roadways. While pass-by trips are new trips at the access points to the site, they are not new trips on the adjacent roadway systems. Since the proposed development will include a residential Development, no pass-by trips are expected for such a development. Therefore, no reduction for pass-by trips considered.

3.1.2 Internal Trips

An internal trip is a trip that has both its origin and destination within a multi-use or mixed-use development area under investigation, which should be deducted from the total number of trips departing and entering the study site. The appropriate internal trip reduction rates are based on the characteristics of the mixed land uses. The proposed development will include a residential land use, hence internal trips are not expected for such development. Therefore, no reduction for internal trips considered.

3.2 Trip Distribution

The directions from which vehicles will approach and depart a site is a function of several variables, including the population and employment distribution within the development’s area of influence, the operational characteristics of the road system, and the ease with which drivers can travel over various sections of the roadway network without encountering congestion. The directional distribution of new project trips by the proposed Residential Development was estimated based on existing traffic patterns coupled with the above factors. The resulting directional distribution are as follows:

• 48% of site generated trips will travel to and from the north on Helmcken Road.
• 48% of site generated trips will travel to and from the south on Helmcken Road.
• 04% of site generated trips will travel to and from the east on Eltham Road.

The resulting traffic direction of approach and site access distribution is illustrated on Figure 4.

3.3 Trip Assignment

3.3.1 Site Generated Traffic Volumes

The projected peak-hour generated traffic volumes for the proposed 20-Unit Residential Development were assigned to the adjacent roadways based on the estimated directional distribution as shown on Figure 4. The resulted site generated AM peak hour and PM peak hour trips are illustrated on Figure 5.

3.3.2 Post Development Traffic Volumes

To determine the Post Development traffic volumes, the Existing 2022 traffic volumes shown on Figure 2 were added to development’s site-generated trips shown on Figure 5. The resulted Post Development, Opening, peak-hour traffic volumes are illustrated on Figure 6.

4.0 EVALUATION AND RECOMMENDED IMPROVEMENTS

4.1 Level of Service Criteria for Intersections

The intersections identified for the study were analyzed according to the methodologies presented in the 2016 Highway Capacity Manual (HCM 6th Edition). The analysis determines the "Level of Service (LOS)" of unsignalized intersections considering the factors including but not limited to number and types of lanes, traffic volumes, heavy vehicle composition, peak hour factors, pedestrian activities, etc. Levels of service are expressed in a range from "A" through "F," with "A" being the highest level of service, and "F" representing the lowest level of service. Table 4 shows the thresholds for Levels of Service "A" through "F" for unsignalized intersections that were evaluated under the current study. For comparison purpose, Table 5 presents the LOS criteria for signalized intersections.

Table 4: Level of Service Criteria for Unsignalized Intersections *

* Note: Capacity analysis for two-way stop-controlled intersection provides the LOS for the critical movements, not of the overall intersection.

Table 5: Level of Service Criteria for Signalized Intersections

4.2 Capacity and Level of Service Analyses

Capacity and level of service analyses were conducted for the following conditions:

• Existing 2022 Traffic Conditions.
• Post Development Traffic Conditions (with site traffic).

The software package Synchro 10 was utilized for the capacity analyses of study intersection and all site accesses. Synchro software utilizes Highway Capacity Manual (6th Edition) methodologies for the evaluations.

Note that the observed heavy vehicle percentages were utilized in the capacity analysis of study intersection. However, for the approaches where the observed percentage was less than 2% a heavy vehicle percentage of 2% was utilized in the capacity analysis software for that approach.

4.2.1 Existing 2022 Traffic Conditions

Existing 2022 capacity, 95%tile queue length, delay per vehicle, and level of service analysis results for the study intersection are presented in Table 6. These results were taken from the HCM 6th Edition Un-Signalized Intersection Capacity Analyses Reports produced by Synchro software.

The detailed Synchro capacity and LOS analyses reports for all scenarios are contained in Appendix C of this report.

Table 6: Capacity Analysis for Existing 2022 Traffic Conditions

(a) The V/C values presented are for the movements with highest V/C within that approach

A review of Table 6 indicates that the study intersection is currently operating at acceptable levels of service including the stop sign controlled approach during both the AM and the PM peak hours. There is no queuing issue at any of the study intersection’s approaches. Therefore, no mitigation is needed under existing traffic conditions.

4.2.2 Post Development Traffic Conditions

LOS and capacity analyses results for the Post Development, Opening, traffic conditions (with site development generated traffic) for study intersection and site access intersection are presented in Table 7.

Table 7: Capacity Analysis for Post Development, Opening, Traffic Conditions, Updated

(a) The V/C values presented are for the movements with highest V/C within that approach

A review of Table 7 indicates that the major study intersection would continue to operate at acceptable levels of service including the stop sign controlled approaches without any issues, during both the AM and PM peak hours. Also, the site access intersection at Eltham Road would operate at acceptable levels of service. Therefore, no mitigation would be required under the Post Development traffic conditions.

4.3 Intersection Layout Assessment, Left Turn Requirement

The Intersection layout assessments were conducted based on TAC Guidelines as per the "Geometric Design Guide for Canadian Roads", June 2017 Edition. The concern for the study intersection of Helmcken Road and Eltham Road is the SB left-turn and the WB left-turn movements. The following was excerpted directly from the above referenced guide:

"Left-Turn Lane Warrants: Page 122:

9.17.2 GUIDELINES FOR THE APPLICATION OF LEFT-TURN LANES The left-turn lane requirements for two-lane and four-lane divided, and undivided roadways are based on volumes warrants and collision warrants."

Volume Warrants

Volume warrants for left turns are typically based on capacity analysis. When opposing traffic volumes are such that left-turning vehicles must wait for a gap to make their turn, they interfere with the through traffic. The magnitude of this interference depends on the opposing volume, the advancing volume, and the percentage of left-turning vehicles. When traffic signals are warranted, storage lengths are subject to the signal cycle timing.

Safety Warrants

A left-turn storage lane maybe also considered at locations where four or more collisions related to left turns occur per year, or where six or more occur within a period of two years, provided the collisions are type that could reasonably be expected to be eliminated by providing a left-turn lane. The minimum storage length for the collision warrant is 15 m.”

As per the above guidelines, the volume warrants are typically based on the capacity analysis. Since the completed Synchro capacity analysis for existing 2022 and Post Development conditions did not show any operational deficiency or unacceptable levels of service, the installation of a left-turn only lane in the SB or in the WB are NOT warranted based on volume warrants. Refer to Table 7 above that presents the capacity analyses results for the Post Development conditions. The SB left-turn would operate at LOS “A” and the WB approach would operate at LOS “B”, with almost no queues forming.

In order to check if exclusive left turn lanes are warranted based on the safety warrant criteria, the past five-year collision data was obtained from the Insurance Corporation of British Columbia (ICBC) from their online collision history page. The links to the website statistics, and the specific link to study intersection’s collision data follows, respectively:

1. https://www.icbc.com/about-icbc/newsroom/pages/Statistics.aspx
2. https://public.tableau.com/app/profile/icbc/viz/VancouverIslandCrashes/VIDashboard

Figure 7 below presents a screenshot that was taken directly from ICBC website. The total number of crashes that occurred between 2017 and 2021 at the study intersection was 2 crashes only. Addoz Engineering Inc. tried to obtain more details about these two crashes such as date of occurrence, type of crashes, etc. However, this data could not be disclosed by ICBC as it is connected to the specific vehicles that were involved in the collisions, and Licence plate numbers are required to obtain collision details.

Going back to the safety warrant, considering the worst-case condition, which is the two crashes occurred in the same year and were related to left-turns (SB or WB), exclusive left-turn lanes are not warranted because the safety warrant states that “four or more collisions related to left turns occur per year, or where six or more occur within a period of two years”. Since only two collisions occurred at the study intersection, the warrant has not been met. Therefore, SB and WB left-turn only lanes are NOT warranted at the study intersection.

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4.4 Access and Major Intersections’ Sight Distance Review

There are two types of sight distances that could be evaluated at the at-grade intersections, the first is for vehicles approaching the intersection and the second is for vehicles departing the intersection from the stopped position. Both sight distances were evaluated in the field at Eltham Road and the proposed site access intersection as well as at the Helmcken Road and Eltham Road intersection. The requirements along with the field observations for each sight distance are presented below:

I. SIGHT TRIANGLE FOR APPROACHES

On the approaches to an intersection, the required sight distances depend upon the approach speeds and the particular action that the drivers may be required to take before reaching the point of potential conflict. In general, each driver has four possible actions: accelerate, continue at present speed, slow down or stop.

Many of the urban road intersections in British Columbia generally have a stop control for intersecting road and free flow for the main road. This is also true for the study major and site access intersections. The Helmcken Road and Eltham Road intersection has a stop sign control on Eltham Road approach and free flow on Helmcken Road north/south approaches. Similarly, the site access would have a stop control on the access approach and free flow on the Eltham Road east/west approaches. To determine the minimum sight tringle for the study intersections, Figure 8a that contains the sight distance and visibility at 90° intersections for approaches with stop control was consulted.

The posted speed limit on Helmcken Road is 40 Km/h and the prima facia speed on Eltham Road is 30 Km/h. For purposes of this analyses, the posted speed limit has been considered to be the design speed, which is 40 Km/h for Helmcken Road and 30 Km/h for Eltham Road. Based on the above criteria and reviewing the table shown on Figure 8a below, the minimum sight triangle values required for approaches at the study intersection are determined as follows, refer to the sight triangle shown on Figure 8a with yellow highlights:

The a = 30 metres and the b = 25 metres