v. weld county road classification plan county 2035 transportation plan public works page 62 v. weld...

WELD COUNTY 2035 TRANSPORTATION PLAN

Public Works Page 62

V. WELD COUNTY ROAD CLASSIFICATION PLAN The functional classification plan is a qualitative guide utilized by both the Planning and Engineering Departments. The functional classification map does not dictate how a road is built. Construction based on the functional classification is quantitative and using best engineering practices is determined based on traffic volumes, development triggers, road quality, safety, and cost benefits.

A. Forecasted Growth Before you can run a travel demand model, you have to generate a land use model. The land use model contains household and employment information that is input into the travel model to provide future travel forecasts. Weld County does not currently have the software capabilities to perform modeling analysis. Therefore, Weld County contracted with Felsburg, Holt & Ullevig (FHU) to run these models. Due to the cost, time, and staffing issues associated with creating one travel model for Weld County, it was determined to use the existing models from DRCOG and the North Front Range (NFR). For Weld County, the models were run using the collector and arterial road network, and a growth factor was applied to all local roads. The modeling roadway network is represented in Figure 20. Figure 20: Modeling Roadway Network

FHU began the modeling process by refining the DRCOG and NFR models based on the county’s roadway inventory spreadsheet, as well as using current land use data. The results from the model runs were used as the basis for determining the 2035 average daily traffic (ADT) for the segments in the roadway inventory spreadsheet, which can be found in Appendix A. Initially,



every segment within the DRCOG and NFR models were recorded into new columns, and then were compiled into one consistent column titled Model 2035 ADT. This process included evaluating the buffer along the WCR 34, which is included in both the DRCOG and NFR models. A two mile buffer on the north and south sides of the shared model area was also evaluated to ensure consistent east-west and north-south volumes. After determining the forecast volumes which had been directly modeled in the DRCOG and NFR models (for collectors and arterials), it was necessary to determine general growth rates for all the remaining road segments (local and subdivision streets within the model area plus all County roads in the northeastern portion of the County, which is not in either model) in the spreadsheet. To account for different development patterns in Weld County, eight development sub-areas were developed, each with its own growth rate. The sub-areas were defined as follows, and mapped in Figure 21: 1. North of SH 392, East of Weld County Line, South of WCR 100, West of US 85; 2. North of SH 392, East of US 85, South of WCR 100, West of WCR 73; 3. North of SH 60, East of Weld County Line, South of SH 392, West of US 85; 4. North of WCR 32, East of US 85, South of SH 392, West of WCR 73; 5. North of SH 66, East of Weld County Line, South of SH 60, West of US 85; 6. North of Weld County Line, East of Weld County Line, South of SH 66, West of US 85; 7. North of Weld County Line, East of US 85, South of WCR 32, West of WCR 73; and 8. Remaining Rural Weld County, East of WCR 73, North of WCR 100. Figure 21: Subarea Growth Factors Map



The 2009 ADT on all County roads within each sub-area was utilized to develop sub-area growth rates for regions 1-7. The County did not include State or Federal Highways as part of this modeling effort. Additionally, the roadway inventory included approximately 500 subdivision road segments, which received their own growth rate. These roadways are located in existing residential subdivisions and are likely to see very little growth once the neighborhood is completely built out. The growth rate for sub-area eight was calculated using population growth data from the 2000 Census. The 2005 and 2035 population estimates for Weld County within the DRCOG and NFR model areas were subtracted from the corresponding total county population to estimate 2005 and 2035 populations for northeastern Weld County. The growth rate for sub-area 8 was applied to all Weld County roadways outside of the DRCOG and NFR model areas. The resulting annual growth rates and associated growth factors (assuming growth between 2009 and 2035) for each of the eight sub-areas are shown as follows in Table 9: Table 9: Sub-Area Growth Factor

UBAREA GROWTH FACTORS

SUBAREA Σ 2035 ADT Σ 2009 ADT GROWTH RATE GROWTH FACTOR 1 246,315 76,841 0.045 3.21 2 101,996 55,387 0.023 1.84 3 663,308 86,284 0.078 7.69 4 595,527 186,359 0.045 3.20 5 516,256 74,059 0.075 6.97 6 366,882 73,679 0.062 4.98 7 294,564 77,461 0.051 3.80 8 0.012 1.38

Residential 0.004 1.10

By applying the above growth rate to all un-modeled road segments, all roadway segments with known counts were assigned an ADT. By combining these new ADT values with the model results, the majority of segments were assigned forecast 2035 volumes in the roadway inventory spreadsheet. With this information, the volume/capacity (V/C) ratios could then be calculated for each road segment. In order to calculate the planning-level traffic capacities, characteristics for different rural roadway types were used. These capacities represent the maximum capacity, which corresponds to the breakpoint between level of service (LOS) E and F. First, all gravel roads were identified and assigned a capacity of 100 vpd per lane. After identifying the gravel roads, all the paved roadways were divided by functional classification. The capacities in Table 10 were then assigned per lane to determine the capacity of each roadway. Since the majority of Weld County roads are characteristically rural rather than urban (4 lane, curb, gutter



& sidewalk), Table 10 shows the rural capacities that were calculated, and best represent the Weld County roadway network. Table 10: Capacity (VPD/Lane)

CAPACITY (VPD/LANE)

GRAVEL 100

SUBDIVISION 1000

LOCAL 1500

COLLECTOR 2300

ARTERIAL 3650

The resulting road segment capacities were then used to calculate the Current V/C and 2035/Existing Capacity for each roadway segment. Weld County recognizes a LOS C threshold for planning purposes, and therefore, a V/C of 0.7 was used as the threshold. All proposed roads were assumed to be two lane facilities in order to provide a capacity and corresponding V/C ratio. In cooperation with FHU, the Traffic Analysis Zones (TAZs) for both models were expanded to the east and renumbered as shown in Figure 22 in red on page 65. Due to Weld County’s large geographic area, the traffic analysis zones tend to be very large. Since large TAZs tend to provide less detail than core modeling areas, the TAZs were redefined to better reflect travel patterns in Weld County. In order to identify potential improvement projects for Weld County’s transportation system, it is important to understand the nature and volume of traffic, as well as existing traffic flow patterns. Demographic data sets, including household and employment estimates and forecasts associated with a system of TAZs, form the basis for travel demand forecasting. The TAZ system for the NFR and DRCOG models are shown in Figure 22. The Weld County 2035 Modeling project is a network-level planning exercise intended to provide broad information about future transportation needs in Weld County.



Figure 22: Weld County Traffic Analysis Zones (TAZ's)

NFR TAZ Structure with splits

DRCOG TAZ Structure with splits


Public Works 7

B. 2035 Traffic Volume Projections All the information from the DRCOG and NFR modeling efforts were used in conjunction with Weld County data for existing platted subdivision and undeveloped recorded exemption lots, along with forecasted growth rates (table 6) from sources including the recently updated 2010 Impact Fee Study and Transportation Plans from the individual communities to generate the 2035 traffic volume projections, an example of which are shown in Figure 23. The 2035 daily traffic projections are shown in Appendix A of the roadway Inventory. The 2035 projections on the county road network range from less than 100 vpd to nearly 37,850 vpd. The roadways with the highest growth rates are projected to increase in daily traffic volumes at a rate of over 7 percent per year. This high growth area is generally located south of SH 392, north of SH 60 and west of US 85. Weld County Road 62 (Crossroads) near Windsor is projected to have the highest daily traffic volume (37,850 vpd) on the county road system in the year 2035; this reflects an average annual growth rate of approximately 7.69%. The county roads in the northern and eastern portions of the county are projected to experience traffic volume increases at a rate of approximately one percent per year, yielding traffic projections generally under 500 vpd. Traffic projections were also considered for roadways not yet constructed, such as the O Street Alignment. If this alignment were constructed the average daily traffic volumes in 2035 would be more than 42,000 vpd.

Figure 23: 2035 Traffic Model



Upon taking into consideration all the changes that have occurred since the 1995 road classification map, the strategic roadways map, the modeling efforts of FHU, and feedback from the surrounding communities, Weld County is recommending a new future roadway plan. The recommended road classification plan and standards presented in the next section are intended to cover the entire county, including those unincorporated area roads transitioning into the local jurisdictions.

WCR 58 over the South Platte River



C. Future Roadway Plan In developing a comprehensive transportation plan for Weld County, a series of meetings with elected officials, staff and other communities were held and significant research was conducted. This chapter of the report presents a summary of the various issues and research conducted toward developing a county-wide Transportation Plan. As mentioned in chapter three, the existing Roadway Classification System is comprised of three primary classification categories including arterial, collector, and local roads. As such, it makes sense to begin with the current roadway classification system and determine if any roads should be modified. Any changes would be based on the criteria presented in Table 11, which defines the classification types. Roads fall within two primary categories of classification: Urban and Rural. To keep the classification simple, the classifications were not further dissected into major and minor roadway classifications. The Urban and Rural categories are further described in Table 11 below, which presents the basic definitions of each. Most of the county roads meet the Rural Road standard. The Urban Road standard is intended only for those unincorporated roads that are county-maintained and located within a municipal urban growth area. These portions of road would eventually be annexed into the surrounding communities, for example portions of WCR 13 between Firestone, Frederick and Dacono, which may still fall within the County’s jurisdiction, but will eventually be annexed to an adjacent community. These roads would provide the transition between the county road standard and the municipal street cross-section. The rural road standard would be applicable to all other county roads.

Arterial - WCR 74

Collector- WCR 51

Local - WCR 93



Table 11: Road Classification Definitions

Roadway Classification

Continuity Service Between

Major Origin/Destination

Average Trip Length

(Connectivity) Spacing Daily

Traffic

Rural Roads

Arterials

County-wide; Extension of

State Highway System;

Moderate to Long.

Serves as connection to

larger communities.

Mostly longer trips to/from

major communities.

As appropriate to serve density

of area; relatively

infrequent on average 2-3

miles spacing

varies

Collectors

Intra County Short to

Moderate.

Serves smaller communities/low

density areas.

Mostly moderate

length trips between smaller

communities; some trips delivered to/from arterials.

As needed to serve density of

local area; recommend no

less than ½ mile spacing.

varies

Local (paved and unpaved)

Short to Moderate.

Serves low density areas and smaller

subdivisions.

Mostly local traffic.

As needed to serve density of

local area; varies

Urban Roads

Arterials

Intercommunity and intra-city

traffic movement or serves major

activity centers.

Extension/ enhancement of

rural arterial system; limited

intra-area service.

Mostly longer trips to/from other county communities.

Partially driven by connection

to rural arterial; no less than

one mile.

>7,000 vpd

Collectors

Link local roads to the arterial

system. Within unincorporated

county area; relatively short.

Extension/ enhancement of rural collector

system through area; intra-area

service, also providing local

circulation service.

Mostly short to medium trips

within unincorporated area; some trips

delivered to/from arterials.

Approximately half mile

spacing with arterial

network.

2,000 -7,000

vpd

Local/subdivisions (paved)

Short; access route.

Provides local access.

Mostly local traffic.

⅛ mile to ¼ mile with

arterial and collector network.

<2,000 vpd



D. Functional Classification Definitions The three primary considerations in classifying Weld County roadways are more thoroughly described as follows:

1. Connectivity This consideration pertains to the nature of the area(s) that a roadway serves and is primarily an issue for the rural areas of the county. For arterial roads, the connectivity characteristic is that it serves a major community, or series of municipalities within the region. Arterials allow direct entry into/out of the larger jurisdictions, and they extend to/from other major communities or major roadway facilities. Portions of the County arterial system could also serve as an extension of the State highway system where State highway designations abruptly terminate, or where county arterial roads parallel the State system, such as WCR 49 to US 85.

As mentioned, collector roads have a mobility function within the rural areas of the County. In this sense, collectors are a subordinate arterial roadway. Collectors should serve as the primary links to/from the smaller communities where arterials are not present. Collector roads may also be designated in low density, low-volume areas where there are missing mobility links and an arterial designation would be overkill.

A review of various references and standards of other Counties revealed that the current Weld County traffic volume thresholds are typically low. A local road, for example, can typically accept between 1,000 and 2,000 vpd in an urban setting and potentially more in a rural area. Standards for collector roads indicate that they can comfortably carry up to 7,000 vpd. Beyond this volume, an arterial roadway should be considered. However, development of auxiliary lanes can significantly improve traffic flows, and therefore should be considered prior to constructing four through lanes, which may be necessary once the volumes exceed 15,000 vpd.

Northbound WCR 49



2. Continuity of Roadway Continuity is a relative measure and is not an absolute. The continuity of road may vary between urban and rural areas. The continuity of an unincorporated road in close proximity to an urbanized area will be gauged against the size of that area, whereas the continuity of roads in rural areas should be considered within the context of the entire County roadway network. A road that might have a significant amount of continuity does not automatically qualify to be an arterial or even a collector. Rather, possessing some degree of continuity is one characteristic of the roads which are designated as collector or arterial roads. Also, continuity may come in a disjointed form similar to the east-west collectors in northern Weld County which make use of multiple County Roads 122, 120, 134, 135, and 132.

3. Traffic Volume Thresholds Arterial roadways usually involve all three functional characteristics (continuity, connectivity, and daily traffic). Since these roads are typically the most continuous and connected, they by default tend to carry the most traffic; therefore, daily traffic thresholds for the roadway classifications is another tool to consider when analyzing road classifications. Historically, Weld County roads do not carry high traffic volumes, so the proposed capacities are intended to be more indicative of rural county traffic flow. For Weld County, any road carrying more than 7,000 vpd is a strong candidate for an arterial road, and any roadway carrying more than 2,000 vpd and less than 7,000 vpd is a candidate for being a collector road, and local roads for volumes under 2,000 vpd. There will be many exceptions in which an arterial might be identified for volumes under 7,000 vpd. For example, some of the Strategic Roadways, shown in Figure 1, were identified as arterial roads, but generate less than 7,000 vpd, yet were established because of the regional corridor connection they provided. However, it is highly unlikely that a local road designation will be assigned for volumes greater than 2,000 vpd, or a collector road for volumes greater than 7,000 vpd.

WCR 29/71st Ave



In Summary, daily traffic volumes alone should not be the only factor relative to classification designation. An appropriately defined roadway classification may sometimes carry traffic volumes well below its typical threshold. Other classification characteristics should be defined as part of the plan including roadway’s continuity, service between activity centers (connectivity), relative trip length of traffic utilizing the road, and approximate spacing of parallel facilities. The continuity element of each classification should be more continuous than that for local roads. The connectivity component should generally recognize that arterial roads tend to serve larger activity centers than collector and local roads, and relative trip length is typically longer along arterial roads than the collector or local roads. The spacing between roads for each classification will need to vary according to the surrounding environment. In general, parallel arterial roadways should be spaced further apart than parallel collector or local roads. For example, in a rural application this can mean arterial spacing every 2-4 miles.

Westbound WCR 60.5



FUNCTIONAL CLASSIFICATION MAP SUMMARIZED The functional classification map shall be used as the official future roadway plan for the County. This is why the functional classification map is one of the more important transportation planning tools associated with the Transportation Plan. Weld County took into account all the municipal transportation plans, the 1995 Transportation Planning Map, 2035 modeling results, and the existing planning/alignment studies to formulate a revised more current functional road classification map. The results of this effort are depicted in Figure 24, which is the recommended County Road Classification Map depicting arterial, collectors, and local roads.

In addition to revising the functional classification map, the County also revised the existing typical road cross sections to include an interim and ultimate section. While it is important to try and reserve the ultimate right-of-way section, funding availability does not always allow for construction of the ultimate section, and therefore, an interim section should be considered until funding becomes available. The width of a roadway is an important design consideration to ensure the road network is appropriately sized to serve its function. The cross sections are located in Appendix C of the Transportation Plan.

WCR 77

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LegendLocal PavedLocal GravelAlignments Not ConstructedCollectorArterial

Weld County Functional Classification Map

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Figure 24: Functional Classification Map

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Typewritten Text

Page 75



E. Updating the Road Classification Plan This section is intended to provide guidance in maintaining the County’s roadway classification system. As conditions change, the County should review all of the roadways and determine if a change in road classification is appropriate. It is recommended that this exercise be conducted at least once every two years. This will ensure that proper actions can be taken to preserve right-of-way necessary for the ultimate construction of each roadway as needed.

The definitions of each classification were previously discussed and summarized in Table 11. These definitions can also be used in determining if any classification adjustments should be made to the system. Considerations in making changes include the following:

1. Daily traffic volume (existing and future) 2. Continuity of roadway 3. Connectivity between communities

These considerations are most applicable to the rural areas. A key factor for the unincorporated area roadways is to maintain close coordination with the local jurisdictions. The County should be proactive with local jurisdictions to the point that arrangements are made to notify and communicate any planning efforts which might affect an entity’s road system. This effort could be accomplished through a standard referral process, and should be a future transportation plan goal for Public Works. The County should also consider streamlining the internal communication referral process by moving to an electronic referral process. It is imperative the County Public Works and Planning Departments coordinate closely to ensure development information is forwarded to the appropriate staff to monitor these roadway classification changes.

WCR 76



F. Road Classification Guide To assist staff and elected officials with classifying roads, a road classification guide was developed. This guide takes into consideration the classification definitions and graphically displays the process by using two different kinds of flow charts. However, since Weld County’s roadway network is so diverse, a “one-size fits all” flow chart for modifying road classifications was complicated to generate. This is because Weld County does not simply use one criterion as a starting point for classifying a road, but uses an all encompassing approach, which factors both qualitative and quantitative measures, as previously described in Chapter III. As a result, urban and rural flow charts were created. Since the determination in identifying the appropriate classification for roads varies between rural and urban roads, both flow charts can be used as a guide in identifying the appropriate roadway classification. The first flow chart is for urban roadways (i.e. subdivisions and high density population or activity centers) as shown in Figure 25. To address the more rural roadway network, a separate rural flow chart was created and is represented in Figure 26. Since classifying a road is not solely based on traffic counts, and many of the rural county road’s traffic counts vary, other criteria should be considered when modifying a rural road classification. For the urban road classification guide, the Highway Capacity Manual helps provide criteria for classifying urban roads. Typically, existing and projected traffic volumes are the first consideration. As illustrated in the flow chart, any county road which is expected to carry over 7,000 vpd should be classified as an arterial roadway. For volumes between 2,000 and 7,000 vpd, the roadway should be at least a collector roadway and potentially an arterial. Below 2,000 vpd, a local road designation will be applied. For the rural road classification guide, however, traffic volume is not the only way to measure the usage of a road. Any one of the three classifications is possible for rural areas. The designation will depend upon the area(s) being served (the road’s connectivity), the nature and classification of alternative parallel routes, and the continuity of the road in question. Therefore, since traffic volumes fluctuate, rural roads should be classified on more than one criteria, and not solely on volume. These flow charts may not address every conceivable scenario for classifying a roadway, but they serve as a general guide to assist the County in determining if any classification changes might be necessary in the future. If unique circumstances exist, some judgment must be exercised in using the flow charts. Some examples for classification consideration include:



1. Type and magnitude of travel generators; 2. Route feasibility and directness of travel; 3. Traffic characteristics and trip length; 4. Spacing between types of functional classes; 5. Continuity of various functional classes; 6. Multiple service capability (accommodation of other modes of

transportation); 7. Relationships of functional classes to transportation plan(s); 8. Integration of classifications of adjoining jurisdictions; 9. Miles and travel classification control values, such as access; and

10. New development.

East 18th Street



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Figure 25: Guide to Modifying Urban Road Classifications

ARTERIAL

COLLECTOR

ARTERIAL

ARTERIAL

COLLECTOR OR

LOCAL

COLLECTOR

LOCAL

COLLECTOR LOCAL

Volume >7,000 vpd?

Volume > 2,000

vpd?

Does Roadway

Serve A Larger Community, Employment

Center, or Major Destination?

Is Roadway

More Continuous

Than Nearby Alternatives?

Does Roadway Serve A Larger

Community?

Is Roadway

More Continuous


Does Roadway

Also Serve A Smaller

Community?

Does Roadway Serve A Smaller

Community?

Is Roadway

More Continuous


Is Roadway

Needed for Continuity?

(Missing Link)



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Figure 26: Guide to Modifying Rural Road Classifications

ARTERIAL

COLLECTOR OR

LOCAL

COLLECTOR

LOCAL

COLLECTOR

LOCAL

Does Roadway Serve A Larger

Community?

Is Roadway

More Continuous


Does Roadway

Also Serve A Smaller

Community?

Does Roadway Serve A Smaller

Community?

Is Roadway

More Continuous


Is Roadway

Needed for Continuity?

(Missing Link)

Road Classification for rural roads is primarily based upon continuity and connectivity. Traffic counts are a contributing factor; however, due to lower volumes that can be variable in different locations, traffic counts are not the only determining factor for classifying rural roadways.

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