D-19 CORRIDORcms4.revize.com/revize/howell/document_center/... · D-19 Corridor Concept Plan The design concept for the corridor is centered on the creation of a place where people

D-19 CORRIDOR Concept Plan

Carlisle/Wortman & Associates, Inc. Grissim Metz Andriese Associates, Inc. Birchler Arroyo Associates, Inc.

City of Howell, MichiganMarch 2008

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D-19 Corridor Concept Plan

City of Howell City Council

Geraldine Moen, MayorSteven L. Manor, Mayor Pro TemDawn CooperTom MalloyScott NiblockScott PattonPaul F. Rogers

City of Howell Planning Commission

Geraldine Moen, MayorDawn CooperPaul Streng Susan CooperBrian ShorkeyBernice VervaetMaryanne Vukonich

City of Howell DDA

Charlotte Swann, PresidentSue HamiltonJeffrey HansenVictoria Hartman, Ex-OfficioJacob HeikkinenStephanie SchlittlerGeraldine Moen, MayorCatherine Stanislawski

City of Howell Administration

Shea Charles, City ManagerAmy Connolly, City Planner (former)Erin Perdu, Community Development Director

Acknowledgements

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Purpose of the Concept Plan 1

Design Concept for the Corridor 3

Midtown District 9

Boulevard District 12

South Portal District 16

Implementation 21

Appendix A: Access Management Design Criteria A1

Table of Contents

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The City of Howell is the focus and economic engine of central Livingston County. It is one of several small cities built along Grand River from Detroit to Lansing that traditionally performed as the political and social gathering space for the surrounding region. In a dual role, Howell is the seat of the Livingston County government which intensifies its purpose as a political center. As a central focus, residents, business owners and visitors enter the city from each major direction; Grand River from the east and west; Michigan from the north; and, the D-19 (Pinckney Road) from the south and the I-96 interchange.

The City has turned its attention to improving the D-19 corridor aesthetics and to assert greater control over the traffic congestion that constricts the corridor during rush hours. A streetscape plan prepared by Grissim Metz Andriese provided the concept design for the public right-of-way.

During the process, the City concluded that the well-designed streetscape alone would not provide a comprehensive change to the corridor. There was still the haphazard private development pattern that has incrementally happened over the decades. This pattern compromised the visual aesthetics and functional aspects of the corridor. During this time period, developers were and continue to show interest in large vacant tracts of land near the I-96

interchange at the corridor’s south end. Opportunities for the City to guide total change arrived. This plan is the initial action.

The purpose of the planning process is to make a comprehensive review of the current development pattern of D-19 and provide recommended action steps that can effect change that creates an identifiable district, place to be, alleviate the worst traffic congestion and increase the tax base.

Based on the number of readily apparent vacant and underutilized parcels of land, this area is ripe for investment when market conditions become favorable. Public investment into the streetscape will stimulate investment. City officials recognize this and set upon this planning process with the following objectives:

Create a seamless and integrated district that draws visitors.Bolster and support the downtown businesses.Alleviate traffic congestion and limit the number of traffic accidents.Create a pleasing experience for motorists from I-96 to the downtown.Create a pleasing walking environment for residents and visitors. Capitalize on the opportunity to increase property value.

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Snapshot of Current Development Pattern

Corridor length: Two-thirds of a mile

Property depth: Frontage ranges from around 125 feet to over 1,000 feet deep.

Frontage Land Use: Highway commercial and office north of Mason/Marion Street. Single-family residential, one-story office, highway commercial and vacant property between Mason/Marion and Morgan Streets. Highway commercial, industry and vacant property south of Morgan Street.

Zoning Districts: Primarily B-2 General Business District; Concentration of R-1 One Family Residential District east side of D-19 south of Marion Street; I-1 Light Industrial District for the park/water tower property.

Traffic Pattern: Rush hour congestion, heavy traffic and many drive accesses.

Development Characteristics:• Buildings are not situated in an organized

pattern. • Development has occurred over several

decades contributing to land use conflicts.• Building heights are generally one-story.• Property sizes vary. Large acreage and deep

properties near I-96 to shallow lots at north end.

Purpose of Concept Plan

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Public Input

The planning process started when the City recognized that change for the better was a must for the area south of the rail line. Developable land was in abundance and development pressure was being felt, especially at the I-96 interchange. The logical response was to improve the D-19 road and frontage since it is the “face” of the south portion of the City. The process involved:

A streetscape improvement plan, prepared by Grissim Metz Andriese Associates, provided the foundation of this report’s land use, urban design and traffic recommendations. A kick-off meeting between property owners, city officials and the planning team was conducted on June 13, 2007. Initial observations of the planning team were discussed with the attendees. Insight into the daily functions of the corridor was received.A day-long design work session was held on August 1, 2007. The format included an opening morning presentation on the reasons to plan the corridor to City officials and the Downtown Development Authority. This was followed by a team tour of the corridor and the preparation of planning and design concepts. An evening presentation to the public culminated the day.The team met internally during September 2007 to refine the design concepts.

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The design concept for the corridor is centered on the creation of a place where people want to spend time and no longer with the sole purpose of conveying cars and trucks. It needs to support buildings that stand shoulder to shoulder and frame the sidewalk and street which become a public place and linear park. As opposed to the current pattern, the sidewalk and street become the focus. The concept uses multiple-story buildings to enclose the street space (See the sidebar for a general description of the findings behind this ratio).

Findings

The project team of urban planners, urban designers and transportation planners took a critical look at the corridor and identified three main conclusions.

The corridor does not elicit a sense of place as opposed to the downtown due to lack of building massing and uniformity in setbacks and site design treatments.The pedestrian environment is hostile due the lack of sidewalks, maintenance of existing sidewalks, fast moving traffic and numerous driveways.The development along the corridor simply relates to the D-19 frontage and not to any critical mass to the rear. It is a one-dimensional strand linking I-96 to the City core.

Solutions

During a project team charrette,

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solutions delineating distinct character districts, building siting and height, street and access design and expanding the planning zone were determined to be the course of action that best suits D-19.

Create Three Districts

The corridor as an entirety beckons to be three distinct districts – Midtown,

Boulevard and South Portal. Typical lot size, land use pattern and proximity to downtown change. Differentiation is achieved through subtle changes in land use, building height and streetscape design. Linkages are maintained visually through the use of street trees and landscape zones and functionally through the continuation of a pedestrian sidewalk. Midtown – This northernmost district is near the downtown. The proposed pattern promotes a tightly-woven mixed-use character with three to four story buildings containing ground level commercial with upper level residences. Pocket parks and prevalent outdoor sitting areas encourage pedestrian use. It expands from South Walnut Street to the Marion Street rail crossing to remove the linear aspect and embrace the downtown.

Boulevard – This central portion is intended to provide a link and visual relief between the Midtown district and the highly active vehicular South Portal district to the south. Buildings are massed together as a street frame, but in

a lower height to maintain physical

Design Concept for Corridor

Roundabouts

Roundabouts provide safety benefits over conventional intersections, generally resulting in less severe crashes and fewer injuries. A roundabout that operates within its capacity will generally produce lower delays than a signalized intersection operating with the same traffic volumes and right-of-way limitations. They provide the opportunity to introduce landscaping and possibly public art into the road right-of-way, providing aesthetic benefits.

The State has planned a roundabout at the D-19 / I-96 freeway ramps. It was identified as a way of managing traffic on D-19, north of I-96, without introducing dual left turn lanes. Development of the northwest quadrant of the current intersection without a roundabout would likely result in two through lanes in each direction and a dual left turn lane at the major point of access to this quadrant. A six-lane wide road was not considered to be desirable given the planning context.

Adding additional roundabouts on D-19 at appropriate locations helps to uniquely define the corridor and is consistent with the concept of corridor transformation that is envisioned in the plan.

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continuity from south to north.

South Portal - Large-scale development, such as a planned retail/entertainment complex or a regional medical complex, accommodating greater numbers of vehicles and capitalizing on the proximity to I-96 is encouraged to settle in this district. Multi-story buildings exceeding three levels or an equal height in feet will anchor the vertical pulsing effect at the south.

Buildings

Building location and height play a significant part in setting the character of corridor design. Buildings constructed at a similar dimension from the right-of-way buildings visually organize the district through horizontal alignment. This alignment provides visual continuity, improves communication by limiting the need for excessive signage, and is the key component in creating a proper height to depth ratio for the street space. Using established urban design principles, a visually comfortable human scale is met when the building height to street width ratio is between 1:2 and 1:4. Translated, this means that when lying face down, the number of feet from sidewalk to sidewalk should accommodate between two and four building heights (i.e. a 120 foot street right-of-way should be lined with 2 1/2 to five story buildings).

This preferred ratio is the concept supporting the D-19 vision. The plan gradually transitions the ratio from 1:4 in the South Portal District to 1:3.5 in the Boulevard District to 1:2 in the Midtown District. This transition reflects the different land use and pedestrian character encouraged in each district.

D-19 is a county road connecting the City of Howell to Pinckney. The focus of the street design is to alleviate traffic congestion and to make the pedestrian environment more hospitable by incorporating trees and sidewalks. Overall, D-19 is recommended to transition from a four/five lane cross-section (with safety enhancements) near I-96 to a two/three lane cross-section near downtown. A network of three roundabouts is strategically placed

to lessen congestion and severe accidents.

The existing four-lane cross-section of D-19 provides two through lanes in each direction. Many studies have documented safety issues associated with undivided four-lane roadways. There is a greater incidence of head-on collisions (no separation between opposing through lanes) and the lack of a center left-turn lane requires shifting of through traffic to avoid left-turning traffic in the inside lane. The use of proposed roundabouts will lessen the number of head-on collisions.

The plan recommends a multi-dimensional approach by managing access through restricting drive cuts and installing boulevards and backage roads, smoothing traffic flow with roundabouts and diverting trucks through a by-pass system. Roundabouts are proposed for the D-19 intersections at I-96, Morgan Road and Mason/Marion Street. Their prominence provides a transition point and signals change in design character.

Specific design standards are described within the respective districts. Access management standards are included in the appendix.

Expand the Planning Zone

Public input expressed the need to create a place south of the rail line where people want to be. This direction is established through the expansion of the immediate D-19 frontage which can permit a critical mass of customers for businesses and support a walkable network of path. This occurs on South Walnut in the Midtown District, through a line of townhomes west of the Boulevard District and an expanded grid network of local streets east of D-19. The expanded grid provides alternative methods for resident access helping to alleviate D-19 traffic congestion.

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The current development pattern of D-19 is haphazard in appearance. Disconnected building setbacks and conflicting land uses does not promote the creation of a “place”.

The planned development of D-19 provides physical relationships and continuity creating a seamless district.

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D -

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Mason Rd.Marion Rd.

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I - 96

Railroad

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CITY OF HOWELLD-19 DESIGN PLAN

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January 2008

0 500250Feet

LegendMidtown District

Boulevard District

South Portal

Green Space

Entry to Downtown

Existing Street

Proposed Street

Note: See redevelopment schedules for complete descriptions of district locations; design intent; permissable land uses; and key design features.

Proposed Roundabout

Midtown District- Link corridor redevelopment area to downtown;- Establish "Pulse Point" with 3-4 story buildings;- Mixed Use district with commercial and residential above.

Boulevard District- Change visual character and lessen landuse intensity;- Establish moderate density west of D-19;- Use sensitive building and site density to respect visual character of neighborhood east of D-19.

South Portal- I-96 entry;- Welcome zone "Pulse Point";- Regional draw with planned retail / entertainment / hotel development;- City to prepare concept design and development guidlines.

Carlisle/Wortman Associates, Inc.Grissim Metz Andriese Associates

Birchler Arroyo Associates, Inc.

Vacated Street

replaces street intersections

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Design Intent

The design intent is to add visual prominence and mark this area as a destination through increased height and massing of buildings. With a limited number of vacant parcels, this is a redevelopment zone. Three design objectives are promoted.

Physical link to downtown to physically strengthen the links. Multiple story buildings visually bridge the raised rail grade separating the project area from downtown.Promotes a sense of place by permitting neighborhood convenience commercial, office and residential uses to freely mix providing an alternative living arrangement. The creation of “place” provides an opportunity to draw visitors.Dense building massing and new street trees frame the right-of-way and encloses the space enhancing the scale and comfort for pedestrians.

Description of Area

This district is generally triangular in shape and

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extends east and west of the corridor frontage. It is the northernmost and nearest the downtown of the three corridor districts. Boundaries include a rail line (north and east); Argyle Street (south) and South Walnut Street (west). Land uses include a mix of gas station/convenience stores, vehicle repair and office along the frontage. Beyond the frontage, single and apartment residences are located west and a City service yard is east. A park and public water tower are on the east side of D-19 at the rail line. The non-residential buildings are generally one-story in height. Residences are two stories.

Design Standards

Land Use

Mixed-use buildings with ground level commercial and office and upper level residential and office uses on D-19 frontage.Moderate-density residences between 15 and 30 dwelling units per acre in balance of district.

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MIDTOWN DISTRICT

Street perspective of the Midtown District demonstrating the defining of the public space through building location and streetscape amenities.

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Architecture Design Features

Three to four story buildings.Ground level commercial on D-19 frontage.Front entries accentuated through the use of awnings, overhangs, trim, brick or stone details, change in material or other similar methods.Ground levels shall have floor to ceiling heights of a minimum twelve feet.Transparent glass for a minimum 50% of a ground level fronting a public thoroughfare.Buildings built to front right-of-way and side property lines with exceptions for patios, porches or side access drives.

Site Design Features

Outdoor sitting areas and tables.Off-street parking lots screened from public rights-of-way by knee walls or architectural hedges.Passive parks located at three key locations.

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Street Design Features

The road cross-section for the Midtown District is planned to transition from a two-lane boulevard, which will terminate at the south side of the Mason Road / D-19 roundabout, to a three-lane section. The three-lane section, with center left-turn lane, will offer adjacent parallel parking. The backage road on the west side of the Boulevard District to the south will continue north through the Midtown district connecting to South Walnut Street. The northeast corner of Marion Street and D-19 will include an internal road linking these two streets and opening internal access to this quadrant. The roundabout at Mason / Marion / D-19 will have one-lane, which allows for a smaller diameter cross-section.

The design of the area between the curb and right-of-way line incorporates designated loading areas, landscaping and sidewalk widths with specific intentions as described below:

The sidewalk cross-section incorporates unloading strip at the curb, landscape and street

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Aerial perspective of the D-19 three lane configuration in the Midtown District.

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Plan view of the D-19 right-of-way showing proposed building lines, pedestrian zones, tree zones and traffic lanes.

tree zone and pedestrian movement zone.The pedestrian zone is ten feet allowing unimpeded movement and stopping areas.Street tree and landscape zone provides important design functions:

Visually softens the hardscape of the street, walks and building facades.Adds color and texture for sensory interest.Promotes pedestrian comfort by physically separating the moving traffic, in tandem with on-street parking, from the sidewalk.Physically encloses the sidewalk creating a space defined by height and width that is visually comfortable.

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Design Intent

The design intent is to provide continuity and link the Midtown and South Portal Districts. This is achieved through massing new buildings in a continuous edge, constructing a rear access road and restricting the number of drives on D-19. This area is not anticipated to be a destination and building height is limited below that allowed in the other districts. The lower height allows the corridor pulse concept to take effect. This district has constricted ability to expand beyond its frontage. An established single-family neighborhood and peat bog on the east and an industrial plant on the west provide the limitations. Several design objectives are set forth.

Two-story building heights in tandem with large street trees visually enclose the public street space into a height to width ratio that found to be comfortable for human enjoyment.Buildings are constructed from lot line to lot line to create a continuous building mass

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framing the street.Improve front yard for people use by relocate vehicle access and off-street parking to rear yards. Slow traffic by reducing the number of moving lanes, adding on-street parking and installing a colonnade of street trees.Respect adjacent neighborhood to east.

Description of Area

This central district of the corridor assumes a linear shape due to the physical barriers of an established neighborhood and peat bog to the east of the fronting properties and a job generating manufacturing plant and a manufactured housing community to the west. It is bounded by Argyle Street to the north and Morgan Street to the south. Existing land uses include several traditional highway uses such as fast food restaurants and car washes mixed with offices. The development pattern is of unconnected one-story buildings with D-19

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BOULEVARD DISTRICT

Street perspective of the Boulevard District demonstrating the defining of the public space through building location and streetscape amenities.

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punctuated with several driveways.

Design Standards

Land Use

“Brownstone” style residential (15 -20 units per acre density) with office option for ground level in north half of district.Office and commercial uses in south half of district.Higher-density multiple-story residential development west of D-19 frontage properties.

Architecture Design Features

Two to two and one half story buildings.Front entries accentuated through the use of awnings, overhangs, trim, brick or stone details, change in material or other similar methods.Ground levels shall have floor to ceiling heights with a minimum twelve feet.Transparent glass for a minimum 50% of a ground level fronting a public thoroughfare.Buildings built to front right-of-way and side property lines with exceptions for patios,

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porches or side access drives.


Front yards reserved for landscaping, sitting areas and porches. Off-street parking located in rear yards.


The road cross-section for the Boulevard District is planned to taper from four-lanes divided at the Morgan Road roundabout to a two-lane boulevard. The boulevard will transition to a three-lane section, with center left-turn lane, and there will be two key intersections: one new cross street between Argyle and Pulford and another located between Pulford and Morgan Road.

The Morgan Road roundabout is the beginning of the southern portion of the Boulevard District. As noted above, this roundabout will provide access to the northwest and northeast quadrants of the I-96/D-19 interchange.

This segment of the D-19 corridor will feature

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Aerial perspective showing the landscaped boulevard and curb edge in the Boulevard District.

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parallel backage roads serving the rear of the parcels fronting on D-19. These roads are important to the overall function of the boulevard section, because left turns on D-19 will be limited to two locations between Morgan Road and Mason Street. The backage roads will enhance safety and preserve roadway capacity on D-19, while offering frontage parcels an alternative means of access to the nearby road network. The concept also supports the existing grid road network that already exists on the east side of D-19, south of Marion Street. The grid network is conducive to the pedestrian street network and it permits vehicular traffic to choose alternative routes that are parallel to one another.

The design of the area between the curb and right-of-way line incorporates designated loading areas, landscaping and sidewalk widths with specific intentions as described below:

The sidewalk cross-section incorporates unloading strip at the curb, landscape and street tree zone and pedestrian movement zone.Street tree and landscape zone provides three important design functions:

Visually softens the hardscape of the street, walks and building facades.Adds color and texture for sensory interest.Promotes pedestrian comfort by physically separating the moving traffic, in tandem with on-street parking, from the sidewalk.Physically encloses the sidewalk creating a space defined by height and width that is visually comfortable.

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Plan view of the D-19 right-of-way showing minimum and maximum building lines, pedestrian zones, tree zones, traffic lanes and the central boulevard.

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Design Intent

This district encompasses large vacant development parcels setting it apart from the other areas. The design intent is to guide large scale retail/ entertainment or medical facilities serving the region through the incorporation of design guidelines and a concept plan. This district will be a pulse point but in terms of activity and project scale, not necessarily building height. With the adjacency of the I-96 interchange, the street design will welcome visitors from the region. Pedestrian use remains important but becomes part of a system of private internal walks.

Several design objectives are outlined:

Welcome visitors to the City of Howell and provide direction to downtown.Permit a high-activity node of development with a regional draw to occur. Concept plan and design criteria are prepared by City to guide growth. Development restrains from constructing large open parking lots along the peripheral edge of a site.Truck traffic is intercepted and diverted around

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D-19 redevelopment area via a by-pass street.

Description of Area

The I-96 interchange is the defining feature of this district. It is the regional access and is situated adjacent to large tracts of vacant property. This district is bounded by Morgan Street to the north and I-96 to the south. Development interest in large-scale shopping, medical facilities and entertainment is expected. Existing land uses include several traditional highway uses such as fast food restaurants and car washes mixed with offices. The development pattern is of unconnected one-story buildings and vacant lots.

Design Standards

Land Use

Planned development incorporating retail, hotel and entertainment use.Regional medical complex.Three to four story buildings.A signature hotel or regional medical complex may exceed the maximum number of permitted stories.

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SOUTH PORTAL DISTRICT

Street perspective of the five lane area of the South Portal District demonstrating the more vehicular dominated segment of the corridor.

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Construct a park for residents west of D-19.Significant landscape entries for planned commercial development. Large open parking lots not permitted.A single lane of off-street parking is permitted between the right-of-way and the building façade.A colonnade of trees with landscape strip is required to separate front off-street parking from the public sidewalk.


The South Portal District provides the connection from D-19 to the I-96 freeway. The intersection of the freeway ramps with D-19 have been planned for a modern roundabout enhancement, which is a key concept of the plan. The roundabout provides functional and safety improvements and it provides an opportunity to create an important visual gateway into the D-19 Corridor. For many, it is the first visual cue of leaving the freeway environment and entering the City of Howell.

The proposal for the D-19 corridor in the South Portal District is for a four-lane divided roadway,

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with some portions as a five-lane section closer to the I-96 freeway ramps. This will provided needed capacity and add safety benefits. A second roundabout is proposed in the vicinity of Morgan Road, which will provide access to the northwest and northeast quadrants of the I-96/D-19 interchange area. This location provides separation from the I-96 ramp roundabout and it avoids the placement of dual left-turn lanes on D-19 to serve the inbound traffic to development on the west side of the road.

The design of the area between the curb and right-of-way line incorporates designated loading areas, The landscaping and sidewalk widths with specific intentions as described below:

A landscape and street tree zone with a pedestrian sidewalk provides continuity to the other districts.The sidewalk is eight feet in width with the primary purpose of moving people. A landscape and street tree zone with a pedestrian sidewalk provides continuity to the other districts.

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Street perspective of the sidewalk zone demonstrating the use of street trees, lawn, paving strip and shrub hedge to separate pedestrians from the street traffic and off-street parking.

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Aerial perspective of the four lane boulevard design for D-19.

Plan view of the D-19 four lane boulevard design showing minimum and maximum building lines, pedestrian zones, tree zones and traffic/turn lanes.

Four LaneConcept Design

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Aerial perspective of the four lane boulevard design for D-19.

Plan view of the D-19 five lane design showing minimum and maximum building lines, pedestrian zones, tree zones and traffic/turn lanes. The use of street trees and shrub hedges are important to visually define and contain the vehicular zones.

Aerial perspective of the five lane design of D-19. This view shows the range in setbacks proposed and the resulting diversity in street character.

Five LaneConcept Design

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To implement the recommendations of this plan, three immediate steps can be taken. Drafting and adopting zoning and access management regulations is one step. Conducting a design feasibility study for the roundabouts at Morgan and Mason/Marion Roads, and the truck by-pass route west of D-19 is the second immediate effort. Continuation of the streetscape improvements as planned is the third necessity.

Zoning Amendments

Amendments to the regulations guiding development should be adopted. Based on public input during this process, it appears that new development is not meeting visual or functional expectations of the community. The recommendation is for the City to adopt a hybrid version of a form-based ordinance for the corridor.

A hybrid form-based version puts more emphasis on physical design than land use. As an example, the building height, distance from the street and façade features are considered more important than the difference between an apartment and an office occupying the same building. The D-19 plan emphasizes the built environment over the building occupants. The goal is to create identifiable districts.

A purist form of form-based regulation and conventional zoning are not proposed for the redevelopment of D-19. A form-based code in its purest iteration controls every aspect of architectural detailing. Although effective, it can be time-consuming and difficult to administer. This form of zoning works best in areas with an historic fabric.

A conventional zoning ordinance which the city currently has in place does not promote districts but a collection of disassociated buildings and properties. A district can happen but only by chance. The use open-ended minimum and maximum standards (i.e. minimum setback dimensions) does not necessarily guide sound physical relationships between developments. Access management regulations are integral to controlling traffic conflicts and ultimately minimizing the number of accidents. The appendix of this plan offers a discussion on the elements of traffic management.

Street Improvements

The street improvements are critical to success. They are the public investment portion of the repositioning of D-19 as a “place”. D-19 has a street improvement design in place. Action bringing the concept design to construction is in progress and should be continued. The addition of two additional roundabouts and the vacation/installation of local streets should be incorporated into the construction plans. A key feature of the plan needing further design exploration is the location of a truck-bypass route west of D-19.

Implementation

Form-Based Zoning Technique

• Uses buildings to frame and enhance the public street.• Public right-of-way is treated as a series of linear parks.• Off-street parking does not dominate public view.• Development outcome is predictable.

Conventional Zoning Technique

• Focuses primarily on separating land uses.• Does not conveniently allow a mix of land uses.• Does not address form of a street.• Development outcome not predictable.

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Most streets provide two functions: 1) move traffic and 2) provide access to land uses that abut them. These two principal functions can often conflict because each access point interrupts traffic movement as vehicles turn off and onto a roadway. In order to balance these two road functions, access management techniques should be used. The access management section below describes ways in which the road network’s capacity can be maximized, by reducing the impact of development abutting the major road network.

Access management is usually implemented through the site plan review process, and these techniques should be incorporated into the development review process for all future projects within the D-19 corridor. Reference should also be made to applicable sections of the City’s Zoning Ordinance. Each case will require an individual analysis to determine the appropriate action given the characteristics of the site and use.

Table 1 Spacing Standards for Driveways on Same

Side of Street

Speed Limit (Mph)

Minimum Driveway

Spacing (Feet)* 25 135 30 155

35 180 40 215

45 260 50 or greater 310

* Center-to-center. Note: Greater separation between driveways and street intersections may be required.

Restricting the Number and Spacing of Access Points

Limiting the number of driveways permitted for each land use can help preserve the traffic movement function of a roadway. Proposed and existing land uses should provide the minimum number of driveways needed to provide reasonable

access to a development site. If additional driveways are proposed, additional street frontage for the subject site and appropriate spacing between existing driveways should be provided.

Even if only one access point is proposed, the most appropriate location should be selected to preserve the function of the roadway and, more importantly, to assure public safety. Driveways located too close together are safety hazards and they can negatively impact road capacity. Recommended spacing standards for non-residential driveways on the same and opposite sides of the roadway are provided in Table 1 and Figure 6.

Encouraging Shared Access

Providing shared access to a site reduces the number of access points, preserves the capacity of the road, and can even help to maintain the character of the community. Shared access can be achieved through a variety of techniques including shared driveways, frontage roads, backage roads, and internal connections between sites. As discussed above, access management is critical for non-residential land uses because of their intensive nature and tendency to demand a higher number of access points. Figure 7 illustrates how backage roads can reduce access points, enhance safety, and open up additional property to easier arterial access. Figure 8 shows how many users can share access points.

Figure 6 Spacing Standards for Driveways on Opposite Side of Street

Proposed Driveway

Existing or Approved Driveway Upstream from Inbound Left Turns Into Proposed Driveway

150’ min.

Existing or Approved Driveway Downstream from Outbound Left Turns from Proposed Driveway

250’ - 400’ min.*

* Varies with volume of peak-hour traffic using driveways.

Appendix A: Access Management

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Access/Driveway Design

Another access management technique is assuring proper driveway and intersection design. Driveways should be designed with adequate width, turning radius, and depth to allow automobiles and large trucks to enter and exit a site safely and efficiently. A clear-vision area at the corners of all driveways and intersections is also needed for safe driver visibility.

A backage road provides access to the rear side of commercial properties located between the backage road and an arterial road. It also provides access to properties located on the opposite side of the backage road from the arterial, thus increasing land values and improving access.

In addition, uses that generate high volumes of traffic may warrant the construction of deceleration and acceleration lanes adjacent to driveways and intersections. Left-turn passing lanes or center left-turn lanes may also be necessary. Such improvements are often

identified by the completion of traffic impact studies. In general, traffic impact studies are recommended whenever a proposed land use will generate more than 750 vehicle trips per day and/or more than 100 vehicle trips in one direction during the morning (e.g., 7 a.m. - 9 a.m.) or afternoon (4 p.m. - 6 p.m.) peak hour.

Finally, restricting turning movements at a driveway or intersections is sometimes warranted due to traffic volumes or poor spacing of proposed access points relative to existing driveways and/or intersections. For example, when an existing driveway is too close to an intersection, it is possible to improve the access and safety by restricting turning movements to right turns in and out of a proposed or existing development site. Figure 9 shows examples of how turn movements can be restricted by driveway design.

Figure 9Intersection Channelization

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Figure 7 Backage Road

A backage road provides access to the rear side of commercial properties located between the backage road and an arterial road. It also provides access to properties located on the opposite side of the backage road from the arterial, thus increasing land values and improving access.

Shared access for a number of non-residential uses preserves the road capacity, which is especially important near intersections. Shared parking at the rear of the buildings also helps preserve the aesthetic appearance and character of the community. If shared access drives are not feasible, internal service roads and/or internal parking lot connections between uses should be provided to preserve roadway capacity.

Figure 8 Non-Residential Access

Shared access for a number of non-residential uses preserves the road capacity, which is especially important near intersections. Shared parking at the rear of the buildings also helps preserve the aesthetic appearance

A backage road provides access o the rear side of commercial properties located between the backage road and an arterial road. It also provides access to properties located on the opposite side of the backage road from the arterial, thus increasing land values and improving access.

Carlisle/Wortman & Associates, Inc. Grissim Metz Andriese Associates, Inc. Birchler Arroyo Associates, Inc.

For additional information please contact:The City of Howell

Community Development Department611 E. Grand River Howell, MI 48843

phone: (517) 546-3861web: http://www.cityofhowell.org

Documents

D-19 CORRIDORcms4.revize.com/revize/howell/document_center/... · D-19 Corridor Concept Plan The design concept for the corridor is centered on the creation of a place where people