Section 3

3.1.1

The purpose of access management is to provide vehicular access to land development in a manner that preserves the safety and efficiency of the transportation system. Access management can extend the operational life of roadways, increase public safety, reduce traffic congestion, and improve the appearance along a roadway corridor. This in turn benefits property owners abutting county roads by preserving property values and enhancing development potential.

3.1.2

The WCRC recognizes that the right of reasonable access to public roads is incidental to ownership of abutting land. The goal of the WCRC is to grant landowners access connections for their needs consistent with WCRC access management and access control requirements in the public interest. The WCRC driveway permit process determines the location and design of driveways so as to provide freedom of traffic movement, safety for roadway users, and preservation of roadway capacity. A successful access management program reduces crash potential and preserves capacity by regulating parameters such as driveway location, driveway spacing, driveway design, traffic signal progression, use of channelization, and use of alternate access systems.

3.1.3

Construction of a new driveway, shared driveway, or private road connecting to a county road or reconstruction of a driveway or private road connecting to a county road shall be allowed only after an approved permit has been obtained from the Permit Section. The construction or reconstruction of all driveways or private roads shall be as described in an approved permit and plans or drawings accompanying the permit.

3.1.4

Permits for access connections to public roads shall be issued when consistent with public safety and based upon traffic volumes, drainage requirements, maintenance needs, the character of the use of the land adjoining the roadway, and any other requirements in the public interest. Construction or reconstruction of any driveway or road approach shall be as described in the approved permit and plans or drawings accompanying the permit. Approaches for private roads shall be constructed or reconstructed to the same geometrics and specifications as a new public road unless otherwise approved by the WCRC.

3.1.5

Construction of a new road which will become a public road shall be allowed only after an approved permit for the approach has been obtained from the Subdivision Section. Construction of the approach, tapers, auxiliary lanes and new road shall be in accordance with plans and specifications approved by the Subdivision Section. Geometrics and construction standards may be found in the current Procedures and Regulations for Developing Public Roads which may be downloaded in .pdf format from the WCRC website at http://www.wcroads.org.

3.1.6

When the use of the land served by the driveway is changed or expanded, and the change or expansion may cause the existing driveway to be a potential safety hazard or to be inconsistent with the criteria described herein, the driveway will be considered a new driveway in accordance with MCL ?247.327. Factors that may indicate a potential safety hazard include, but are not limited to, the following:

1. Elevated crash rate
2. Increased traffic volume on the main road
3. Increased turning movements using the driveway or road approach
4. Improper drainage
5. Inadequate sight distance
6. Excessive grades of driveway
7. Improper driveway design for use
8. Change in functional classification of road

3.1.7

The WCRC may revoke any driveway or road access permit if at any time the permitted object, use, or activity fails to meet the requirements of these procedures and regulations, MCL ?247.321 et seq, or the terms and conditions of the permit itself.

3.2.1

A permit granting permission to construct, reconstruct, relocate, resurface, use and maintain a driveway that connects to a county road may be issued by the WCRC only to the property owner or the property owner's authorized representative.

3.3.1

An application for a driveway permit, on forms provided by the WCRC, shall specify the driveway system requested, including the location, number and type of driveways (i.e., 2-way, 1-way, divided, dual service or directional). The WCRC may approve the system as requested or may condition approval on such changes as may be necessary to maintain safe conditions and proper spacing between driveways. Application review will be based on anticipated traffic volumes on the driveways and on the roadway, type of traffic to use the driveways, type of roadside development, drainage, and other operational considerations in the public interest.

3.4.1

With the exception of most applications for residential driveway permits, applications shall be accompanied by three (3) sets of plans or drawings signed and sealed by a Professional Engineer which clearly show the following features:

1. Existing road pavement, ditches, right of way and property lines, road appurtenances, medians (if existing) and dimensions thereof, driveways on adjacent property and on property opposite the frontage, and names of existing and proposed roads.
2. All buildings and appurtenances, both proposed and existing, with dimensions and a notation as to present or proposed use of the buildings.
3. Design standards of all driveways, tapers, through lanes, right turn lanes, left turn lanes, or passing lanes to be constructed, reconstructed, relocated, surfaced, resurfaced, operated, used or maintained shall include the following dimensions and features:
   • widths of all driveways and lanes;
   • radii of driveway returns and other points of curvature;
   • driveway grades or profile view of driveway;
   • road centerline and edge of pavement grades;
   • angle of the driveway(s) relative to the roadway centerline;
   • dimensions of roadside control island and other traffic islands adjacent to the road;
   • driveway surface material and traffic island surface material; and
   • sight distance for the approach.
4. Distance from existing driveway(s) and proposed driveway(s) to the nearest intersecting street and distance from driveways to property lines.
5. North directional arrow and scale of drawing.
6. All roadside features to be constructed within the road right-of-way, including without limitation roadside control island, curb, sidewalks, traffic control devices, manholes, poles, etc.
7. Existing and proposed drainage structures and controls to include:
   • size of drive culvert;
   • type of culvert;
   • type of culvert end treatment;
   • grade of culvert with sufficient elevations upstream and downstream to show the extent of flow across the proposed development and to the proposed outlet;
   • direction of surface water flow on and from adjacent property;
   • drainage structures;
   • drainage plan and outlet for all storm drainage on the site.

3.5.1

The WCRC recognizes the direct correlation between land use decisions and traffic operations. The Applicant's proposed project or development, and its needs for access, will create traffic impacts on the public roads. The intent of these procedures and regulations is to provide a framework for proper evaluation and remediation of those impacts. In order that the WCRC may continue to meet its statutory duty to maintain roads under its jurisdiction in reasonable repair, so as to be reasonably safe and convenient for public travel, the WCRC may require, as a permit condition, the completion by the Applicant's engineer of a Traffic Impact Study. This policy will further promote the following objectives:

1. Provide a standard set of analytic tools and format for traffic impact analysis.
2. Provide a consistent and comprehensive approach to the overall impact of development on the public roads.
3. Allow the community to assess the effects that a proposed project may have on the transportation network by outlining information needed and evaluation procedures to be used.
4. Promote reasonably safe and convenient traffic operating conditions on roads and intersections after development of a proposed site.
5. Reduce the negative traffic impacts created by individual developments, in the interests of the public and of the development, by helping to ensure that the transportation system can accommodate the expected traffic safely and efficiently.
6. Realize a comprehensive approach to the overall impacts of various developments along a corridor or within part of a community rather than a piecemeal approach.
7. Provide direction to governmental agencies and developers of expected impacts of a project.
8. Alert the community, governmental agencies, and developers to the need for improvements or modifications to the roadway, access or site design.
9. Protect the substantial public investment in the existing road system by facilitating the WCRC ability to maintain roads under its jurisdiction as required by statute.

3.5.2

When a Traffic Impact Study is required, it shall be prepared under the direction of an experienced traffic/transportation engineer, licensed as a Professional Engineer by the State of Michigan.

3.5.3

A Traffic Impact Study is a complete analysis and assessment of traffic generated by a proposed development, and of the impact on the surrounding transportation system. A traffic impact study is required for any proposed development expected to generate over one hundred (100) peak hour directional trips, or 750 daily trips, or at the discretion of the Permit Section. The study shall be completed and sealed by a Professional Engineer. If the study includes the review of potential signal operations, a pre-qualified signal operations consultant must be used. Table 1 gives examples of land use that is expected to meet or exceed the 100 peak hour directional trips or 750 daily trips.

3.5.4

A traffic impact study shall include:

1. A narrative summary at the beginning of the report, including, but not limited to:
   1. The applicant and project name.
   2. A location map.
   3. The size and type of development and any adjacent development.
   4. Generated traffic volumes based on type and size of land use which are compatible with those listed in the ITE Trip Generation Manual, or which are developed according to the methodology described in the ITE Trip Generation Handbook.
2. Project phasing identifying the year of development activities per phase and proposed access plan for each phase.
3. A transportation system inventory, which describes the physical, functional and operational characteristics of the study area highway system, and where appropriate, locates transit services. The description shall provide, where pertinent, data on:
   1. peak-hour volumes (existing and projected)
   2. number of lanes
   3. cross-section
   4. intersection traffic signals and configuration
   5. traffic signal progression
   6. percentage of heavy trucks
   7. adjacent and opposing access point locations
   8. jurisdiction
   9. auxiliary lane lengths
   10. grades
   11. functional classifications
4. Site Plan including proposed roadway per phase for each access. Driveway design and roadway improvements shall meet WCRC procedures and regulations.
5. Capacity analysis shall be performed at each access point. Default values shall not be used when actual values are reasonably available or obtainable. The interaction of conflicting traffic movements shall be addressed in the Traffic Impact Study.
6. A Traffic Impact Study shall be analyzed with and without the proposed development and with the proposed development for both existing and projected traffic volumes.
7. The traffic volumes for the development shall assume a total build out and, in the case of multi-phase development, evaluate the cumulative effects of each phase.
8. The completed analysis shall be summarized in a table showing all the Measures of Effectiveness (MOE) for all of the above conditions, as determined necessary by the WCRC.
9. Required operational changes shall be part of the permit approval process.

Table 1: Examples of typical land use size thresholds based on trip generation characteristics
Land Use	100 Peak Hour Trips (Directional)	750 Trips Daily
Residential Single Family Apartments Condominiums/Townhouses Mobile Home Park	150 units 245 units 300 units 280 units	70 units 100 units 120 units 135 units
Shopping Center (GLA) (3)	16,700 sq. ft.	3,400 sq. ft.
Fast Food Restaurant w/drive-thru (GFA) (3)	5,500	1,200
Convenience Store w/gas (GFA) (3, 5)	1,000 sq. ft. or 7 fueling stations	1,000 sq. ft.
Banks w/drive thru (GFA) (3)	4,400 sq. ft.	2,800 sq. ft.
Hotel/Motel	310 rooms	90 rooms
General Office	37,200 sq. ft.	45,000 sq. ft.
Medical/Dental Office	40,800 sq. ft.	26,000 sq. ft.
Research & Development	87,000 sq. ft. or 7 acres	70,000 sq. ft. or 4 acres
Light Industrial	115,000 sq. ft. or 8 acres	115,000 sq. ft. or 11.5 acres
Manufacturing	215,000	195,000
Notes: 1. Rates/equations used to calculate the above thresholds are from Trip Generation Manual, 7th Edition, 2003, by the Institute of Transportation Engineers. This table will likely need updating as future editions provide additional information. 2. For example, a full traffic impact study should be completed (100 peak hour, peak direction trips generated) if 150 or more single family units are proposed for a site. 3. GLA – Gross Leasable Area; GFA – Gross Floor Area. 4. Using AM peak-hour rates/equations would provide a lower threshold. However, adjacent roadway volumes are usually higher during the PM peak hour. 5. Uses both “Service Station with Market” and “Convenience Market with Pumps” data. 6. For further trip generation characteristics of the above land uses, or of other uses not illustrated above, refer to the latest version of Trip Generation.

3.5.5

The Level of Service (LOS) and capacity shall be evaluated for the critical movements at site access points. Also, the traffic study should show the projected level of service for all movements at signalized intersections and for all critical movements at unsignalized intersections. If the LOS of the existing intersections are a "D" or better, and the proposed project will produce a LOS of "E" or worse at one or more movements at a nearby intersection or site access point, mitigation needs to be evaluated. If the intersection LOS is currently an "E?, or worse, the current LOS or vehicular delay must be maintained or improved.

3.5.6

The major benefit of a Traffic Impact Study is to determine what, if any, mitigation measures are needed. The study should present mitigation alternatives and recommendations. Mitigation measures are not limited to physical improvements. Mitigation can include changes to traffic signal timing or reducing the number of trips generated in the peak hour. Sample mitigation measures include, but are not limited to, the following:

1. Roadway Improvements
   • construct an auxiliary turning lane
   • pave the roadway
   • re-align the road
   • improve sight distance
   • widen the roadway
   • intersection improvements
   • add deceleration/acceleration lanes
   • add a median crossover
2. Access Management Techniques
   • increase driveway spacing from intersections
   • relocate driveway or intersection
   • reduce the number of driveways
   • install a median
   • develop a service road system
   • share access with adjacent land
3. Operational Improvements
   • change signal timing or phasing
   • improve signal progression
   • reduce peak hour trips through transit
   • off-peak shift changes
4. Site Plan/Land Use Techniques
   • reduce project size
   • modify project phasing
   • use of traffic control devices
   • pedestrian or bicycle circulation
   • internal circulation
   • service vehicle/truck access or circulation

3.5.7

The study shall include a resume of the preparer and/or relevant experience of the firm responsible for the report and shall be signed by the preparer with full recognition of potential liability for the results and recommendations outlined in the report.

1. Traffic Impact Studies shall meet the requirements of Evaluating Traffic Impact Studies: A Recommended Practice for Michigan Communities, by McKenna Associates, Inc; The WBDC Group which is available in .html format at the National Transportation Library website at http://ntl.bts.gov/DOCS/etis.html.
2. The study shall include a description of the site, surroundings, and study area. Illustrations and a narrative should be included to help describe the characteristics of the site and adjacent road system including functional classification, number and types of lanes, speed limits, and traffic control. The description should include surrounding land uses, expected development in the vicinity which could influence future traffic conditions, special site features, and a description of any programmed road improvements. The study should define and justify the study area selected for analysis.
3. The study shall include a description of the proposed use including details such as land use, the number and types of dwelling units, the gross and usable floor area of buildings, number of employees, shift changes, intended development phasing, potential future expansion, etc.
4. The study shall include a description of existing traffic conditions as follows:
   1. Traffic Counts: Existing conditions including peak hour traffic volumes (and daily volumes if applicable) on roads adjacent to the site. Existing counts and levels of service for intersections in the vicinity which are expected to be impacted, as identified by the community at a pre-application conference or discussion, should be provided for projects requiring a Traffic Impact Statement or Regional Traffic Analysis. Traffic count data shall be not more than two years old, to be increased by a factor supported by documentation or a finding that traffic has increased at a rate less than two percent annually over a period measured by the last three years, four years, or five years.
   2. Traffic counts shall be taken on Tuesday, Wednesday, or Thursday of non-holiday weeks and preferably when public schools are in session. Additional counts, e.g., on a Saturday for a proposed commercial development or a Sunday for a proposed church, may also be required in some cases. The individual or firm performing the impact study shall obtain the traffic counts during average or higher than average volume conditions, so as to minimize weather or seasonal variations, the effects of any construction or special events, etc.
   3. Roadway characteristics shall be described and illustrated as appropriate. Features to be addressed include lane configurations, geometrics, signal timing, traffic control devices, posted speed limits, average running speeds, and any sight distance limitations. Existing levels of service shall be calculated for intersections included within the study area.
   4. Existing driveways and potential turning movement conflicts in the vicinity of the site shall be illustrated and described.
   5. The existing right-of-way shall be identified along with any planned or desired expansion of the right-of-way requested by the WCRC.
   6. Traffic crash data and analysis covering the most recent three years for the study area or proximity to site access points may be required, particularly for sites along roadways identified as critical or congested corridors.
5. A Traffic Impact Statement with a development completion date beyond one year at the time of the traffic study shall also include analysis of forecast traffic at date of completion along the adjacent road network. The forecast shall be based on a network traffic assignment model (if available), historic annual percentage increases and future approved development in the area. Long range projections shall be used when a Regional Traffic Analysis is required.
6. Forecasted trip generation of the proposed use shall be provided for the a.m. and p.m. peak hours and the average day. The forecasts shall be based on the data and procedures outlined in the most recent edition of the ITE Trip Generation Manual and per the methodology as described in the ITE Trip Generation Handbook. The applicant may use other commonly accepted sources of data or supplement the standard data with data from at least three similar developments located in southeast Michigan. Any reduction for pass-by trips, transit, ridesharing, other modes of travel, or internal capture rates shall be based on both ITE findings and documented survey results acceptable to the WCRC. For projects intended to be developed in phases, the trip generation by phase shall be described.
7. The generated traffic volumes shall be distributed (inbound v. outbound, left turn v. right turn) onto the existing road network to project turning movements at site access points and nearby intersections where required. Projected turning movements shall be illustrated in the report. A description of the application of standard engineering procedures for determining the distribution should also be attached (trip distribution model, market studies, counts at existing driveways, etc.). For projects requiring a Regional Traffic Analysis, use of a network traffic assignment model projection may be required to help evaluate impacts.
8. The following impact analyses shall be included in the report:
   1. Level of service and capacity analysis at the proposed access points shall use the procedures outlined in the most recent edition of the TRB Highway Capacity Manual. For projects requiring a Traffic Impact Statement or Regional Traffic Analysis, before-and after-capacity analyses shall also be performed for all intersections where the expected traffic generated at the site will comprise at least five percent of the existing intersection capacity, or for roadway sections and intersections experiencing congestion or a relatively high crash rate, as determined by the WCRC.
   2. Gap studies for unsignalized intersections where applicable.
   3. The WCRC may require a Regional Traffic Analysis which evaluates the impact on the road network over a wide area for up to 20 years for a project of regional significance, if a network model is available.
9. The report shall include a map and description of the location and design of proposed access points (driveways or road approaches) including: any sight distance limitations, dimensions from adjacent driveways and intersections within 250 feet on either side of the main roadway, data to demonstrate that the number of driveways proposed is the fewest necessary, and evidence that the proposed access points will provide safe and efficient traffic operation and will comply with all WCRC regulations.
10. The Traffic Impact Study shall include the following:
    1. Description of any additional right-of-way where planned or desired by the WCRC.
    2. Changes that should be considered to the plat or site plan layout.
    3. Description of any needed non-motorized facilities.
    4. If the use involves a drive-through facility, the adequacy of the queuing/stacking area should be evaluated.
    5. If a median crossover is desired, separate analysis should be provided.
    6. If a traffic signal is being requested, provide the relationship of anticipated traffic to traffic signal warrants in the most recent edition of the MMUTCD. Analysis should also be provided of the impacts to traffic progression along the roadway through coordinated timing. vii. Description of site circulation and available sight distances at site driveways.
11. The study shall outline mitigation measures and demonstrate any changes to the level of service achieved by these measures. Any alternatives or suggested phasing of improvements should be described. The mitigation measures may include items such as roadway widening, addition of turn lanes or deceleration and acceleration tapers, changes to signalization, use of access management techniques or a reduction in the proposed intensity of use. Proposed mitigation measures should be discussed with the WCRC. The responsibility for and timing of roadway improvements shall be described.

3.6.1

The location and spacing of access for commercial driveways and road approaches is an important element in the planning, design, and operation of roadways. Access points are the main location of crashes and congestion. Their location and spacing directly affect the safety and functional integrity of the roadway.

3.6.2

A driveway shall be so located that no undue interference with the free movement of roadway traffic will result. A driveway shall be so located also to provide the most favorable vision and grade conditions possible for motorists using the roadway and the driveway consistent with development of the site considering proper traffic operations and safety. The Applicant shall submit plans showing the driveway layout requested, including the number, type, dimensions, location, and spacing of all driveways. Driveways shall provide the required sight distance and shall provide the most favorable driveway grade reasonably possible.

3.6.3

In general, one access point is adequate for a single business. When one-way pair driveways (In-Out) are requested and the inside traffic circulation promotes such operation, these driveways may be considered as a single access point. If multiple access points are requested, the Permit Section may require a traffic impact study from the business owner/property owner to justify the need for the multiple access points.

3.6.4

Adjacent driveways on the same side of the road shall be spaced as far apart as on-site circulation allows. In some cases the Permit Section may require that the business owner/property owner redesign the site plan, and relocate the access point to meet the desirable spacing distance.

3.6.5

Adjacent property owners may consolidate their driveways by using either a frontage road or a joint driveway system. If the WCRC approves such a system, a driveway permit shall be issued to all property owners concerned and shall state that there is an agreement that all properties shall have access to the roadway via the frontage road and the joint driveway system.

3.6.6

Table 2 shows desirable unsignalized access spacing as a function of posted speed. These distances are based on average acceleration and deceleration considered adequate to maintain good traffic operations. The sight distance at the access points must also be investigated. Driveway spacing in Table 2 is measured from centerline to centerline.

Table 2: Unsignalized Access Spacing (adjacent)
Design Speed (mph)	Center-to-Center of Access (ft)
25	130
30	185
35	245
40	300
45	350
50 and above	455

3.6.7

In the event that a particular parcel or parcels lack sufficient frontage to maintain adequate spacing, the owner(s) have several options:

1. Seek a variance from the County Highway Engineer from the desired spacing, but in no case can the variance be greater than the next lowest classification shown in Table 2. For example, on a 30 mph roadway requiring 185 foot spacing, the distance may be reduced to no less than 130 feet. To minimize left turning conflicts, driveways should be either aligned directly with those across the road, or offset a sufficient distance from those across the road to achieve the minimum spacing standards listed in Table 2.
2. Adjacent owners may agree to establish a common driveway. In such case the driveway centerline should be the property line between the two parcels. The driveway must meet standard specifications, and the estimated driveway volume will be the sum of the trip generation rate of both parcels.
3. In areas where frontage roads or service drives exist or can be constructed, individual properties shall be provided access to these drives rather than directly to the main highway.
4. After all the above options are exhausted, an access point may be allowed within the property limits as determined by the Permit Section.

3.6.8

All frontage roads shall be placed on private property outside of the future right-of-way, as defined by the WCRC.

3.6.9

If the road carries one-way traffic, the dimensions provided in Table 2 may be revised so that the movements creating conflict are discouraged. If the driveway system is on the left-hand side of a one-way road, the dimensions approved shall be based on the same principles as used on right-hand side driveways.

3.6.10

In accordance with AASHTO guidelines, driveways should not be situated within the functional boundary of at-grade intersections. This boundary includes the longitudinal limits of auxiliary lanes. An access point may be allowed within the above boundary if the entire property frontage is located within this boundary.

3.6.11

Restricting or prohibiting left turns at unsignalized access points aligned across from each other can greatly reduce safety and operational problems. Table 3 provides the desirable distances between two access points on the opposite side of the roadway.

Table 3: Desirable Driveway Offsets on Undivided Roadways
Design Speed (mph)	Center-to-Center of Access (ft)
25	255
30	325
35	425
40	525
45	630
50 and above	750

3.6.12

A driveway, including the radii but not including the right-turn lanes and tapers, shall be located entirely within the area between the Applicant's property lines extended to the centerline of the roadway. A driveway radius may extend outside of that area only if the adjacent property owner certifies in writing that he will permit such extension. Driveways, including the radii (but not including right turn lanes, left-turn lanes, passing flares, or tapers), shall be located entirely within the Applicant's right-of-way frontage. This right-of-way frontage is determined by projecting the property lines to the centerline of the road. Radii on adjacent right-of-way frontage shall be permitted only upon obtaining a letter allowing encroachment from the adjacent property owner and when the Permits Section has determined that such encroachment is necessary.

3.6.13

A driveway shall not be constructed along acceleration or deceleration lanes and tapers, unless no other reasonable access point is available. WCRC may require extension of these lanes by the Applicant.

3.6.14

Driveways shall not be constructed along the acceleration or deceleration lanes and tapers connecting to freeway interchange ramp terminals.

3.6.15

The number of residential driveways that may be permitted shall be determined as follows:

1. One (1) residential driveway shall be permitted for each platted lot or for each unplatted residential parcel.
2. Two (2) residential driveways may be permitted for residential property with more than 300 feet of frontage if, in the opinion of the Permit Section, the additional driveway does not create a safety problem.
3. Two (2) residential driveways may be permitted on the same property, in lieu of the above, to serve a circle driveway if the frontage of the property is 85 feet or more at the right-of-way line.
4. Residential driveways on the same property shall be at least 45 feet apart, center-to-center.

3.6.16

Spacing between a road intersection and an access connection shall be sufficient to avoid creating conflicts between driveway traffic movements and road movements at the intersection. The corner clearance required is a function of the types of roads which intersect. In all quadrants of an intersection access points should be located according to the dimensions shown in Figure 1. Table 4 provides the minimum corner clearance dimensions. The spacing requirements in Table 4 are from the centerline of the proposed driveway to the near right-of-way line of the intersecting road.

		Table 4: Corner Clearance
Design Speed (mph)	Dimension	Signalized Intersection Control (ft)		Stop Sign Intersection Control (ft)
25 to 35	A	230		115
B	115		85
C	75		75
40 to 55	A	460		230
B	230		170
C	150		150

3.6.17

The application shall specify the driveway system requested, including the number and type (two-way, one-way, or divided) of driveway(s). The Permits Section may approve the requested system or may require as a condition of issuance that the Applicant make changes to ensure safe operations and necessary spacing between driveways. Such requirements shall be based on anticipated traffic volumes on the driveways and on the road, type of traffic to use the driveway, characteristics of roadside development, and other safety and operational considerations. Generally, only one driveway will be permitted per parcel.

3.7.1

The driveway grade shall be determined using the following criteria:

1. If the road is uncurbed, the grade of the driveway shall meet the existing shoulder.
2. If the road is curbed, the grade of the driveway shall meet the existing edge of pavement.
3. The grade of a commercial driveway shall not exceed a maximum of six percent (6%).
4. The grade of a residential driveway shall not exceed a maximum of ten percent (10%).
5. If the sidewalk elevation must be adjusted to meet the driveway, the slope shall not exceed five percent (5%).

3.8.1

Minimum sight distance for all driveways and road approaches shall be in accordance with the current edition of the AASHTO Policy On Geometric Design of Highways and Streets.

3.8.2

The safety of an access connection is improved where the location and geometrics of the connection are clear to approaching drivers and the driver of a stopped vehicle intending to enter or cross the intersecting road. The area on either side of an access connection should contain a triangular area free of obstructions that might block an approaching or stopped driver's view. To provide for adequate vision, all obstructions must be removed within the clear vision area, otherwise known as a sight distance triangle. A driveway or road approach shall be constructed and maintained at a location along the property frontage that meets or exceeds the requirements of Tables 5 and 6. Should this not be obtainable, then the driveway shall be constructed at a location that provides the distance closest to that required in Tables 5 and 6, provided the stopping sight distance identified in Table 6 is met or exceeded.

3.8.3

Stopping Sight Distance: The following general discussion on stopping sight distance is adopted as excerpted from the 2004 edition of A Policy on Geometric Design of Highways and Streets (AASHTO) page 110:

Sight distance is the length of the roadway ahead that is visible to the driver. The available sight distance on a roadway should be sufficiently long to enable a vehicle traveling at or near the design speed to stop before reaching a stationary object in its path. Although greater lengths of visible roadway are desirable, the sight distance at every point along a roadway should be at least that needed for a below-average driver or vehicle to stop.

Stopping sight distance is the sum of two distances: (1) the distance traversed by the vehicle from the instant the driver sights an object necessitating a stop to the instant the brakes are applied; and (2) the distance needed to stop the vehicle from the instant brake application begins. These are referred to as brake reaction distance and braking distance, respectively.

3.8.4

In computing and measuring stopping sight distance, the height of the driver's eye is estimated to be 3.5 feet and the height of the object to be seen by the driver is 2 feet ( equivalent to the taillight height of a passenger car). 2004 AASHTO Exhibit 3-1 on page 112 also gives stopping sight distances for various design speeds.

3.8.5

Intersection Sight Distance: The following general discussion on intersection sight distance is adopted as excerpted from the 2004 edition of A Policy on Geometric Design of Highways and Streets (AASHTO) page 651:

The driver of a vehicle approaching an intersection should have an unobstructed view of the entire intersection, including any traffic control devices, and sufficient lengths along the intersecting highway to permit the driver to anticipate and avoid potential collisions. The sight distance needed under various assumptions of physical conditions and driver behavior is directly related to vehicle speeds and to the resultant distances traversed during perception-reaction time and braking.

Table 5: Intersection sight distance for passenger cars from stop
Design Speed (mph)	Left Turn (ft)	Right Turn or Crossing (ft)
25	280	240
30	335	290
35	390	335
40	445	385
45	500	430
50	555	480
55	610	530

Table 6: Sight distance for passenger cars left turn from intersecting road
Design Speed (mph)	Stopping Sight Distance (ft)	Intersection Sight Distance (ft)
25	155	205
30	200	245
35	250	285
40	305	325
45	360	365
50	425	405
55	495	445

3.8.6

Sight distance will be measured 10 feet from the edge of the traveled portion of the intersecting road for proposed residential driveways and a minimum of 15 feet for all other proposed access connections.

3.8.7

The sight distances presented in Tables 5 and 6 are valid for passenger cars, two-lane undivided intersecting roads, and when roadway grades are between -3.0 percent and +3.0 percent. Additional adjustment factors, per AASHTO, shall be applied for situations that exceed these parameters.

3.8.8

A permit for an access connection between a property and a public road shall be denied when minimum safe sight distance cannot be attained. When a permit is denied, access may be obtained, at the owner's expense and subject to WCRC approval in one of the following ways:

1. Negotiating with adjacent property owners to acquire access to the subject parcel through easements which facilitate lawful permitted access;
2. Constructing an approved frontage road serving the subject property and connecting with the roadway at a location where a safe driveway can be permitted; or
3. Realignment or reconstruction of the existing roadway to correct the sight distance deficiency. This possibility would require execution of a Road Improvement Agreement as described in Section 3.2.2.

3.8.9

At intersections or railroad crossings where the WCRC owns limited access right-of-way to provide a clear vision area, no driveway shall enter or cross any part of that clear vision area. Where the WCRC has an easement for such clear vision area, driveways shall not be permitted through the clear vision area.

3.8.10

These standards shall be used unless WCRC engineering judgment determines that another value is more suitable for a particular site or a special condition is approved by the WCRC.

3.9.1

Adjacent to driveways, a buffer area between the right of way line and the pavement edge shall be provided as determined necessary by the WCRC to provide a physical barrier between moving traffic and private property. A buffer area is needed to provide an unobstructed vision area and to physically prohibit potentially hazardous movement of vehicles (especially at undesirable angles of approach) from and to the road. Where encroachment by parked vehicles takes place or may take place, the WCRC may require the buffer area to be established by traffic control order and installation of regulatory signs, guardrail, guard posts, curb or equivalent method. In every case, an area of unobstructed vision shall be provided at either side of driveways. This may require the removal of trees, earthen embankments and other obstructions.

3.10.1

The design features described herein with their appropriate illustration of various driveway features as shown in Figure 1 shall be used by the Applicant in dimensioning a proposed residential driveway on plans accompanying driveway permit applications. The dimensions to be used for various driveway design features, shown as a standard with a working range of dimension, are given in Table 7. These standard dimensions shall be used unless conditions warrant a deviation. The WCRC may specify particular dimensions so a particular driveway system will accommodate vehicle movements normally expected without creating undue congestion or hazard on the roadway or to provide reasonable access.

3.10.2

The letters in the following design features refer to features in Figure 2:

1. Intersecting angle, A, the clockwise angle from a roadway centerline to a driveway reference line which is the centerline or the edge of the driveway.
2. Driveway width, B, the distance between driveway edges of pavement or edges of the gravel surface measured at the point where the edges of the driveway become parallel, point b in figure 1. If the right-of-way line is so close to the pavement that point b falls on the applicant's property, then the width of the driveway at the right-of-way line shall be based on the projected driveway width.
3. Entering radius, C, the radius of a driveway edge curve on the right side of a vehicle entering the applicant's property.
4. Exiting radius, D, the radius of a driveway edge curve on the right side of a vehicle leaving the applicant's property.
5. Curb cut, R, the length of the opening along a roadway curb for a straight-sided residential driveway

3.10.3

A residential driveway shall be paved between the edge of the pavement and the existing or proposed sidewalk. If there is no existing or proposed sidewalk, the surfacing shall extend at least 10 feet from the edge of pavement. For a residential driveway, either curb cuts or curb returns shall be required as determined by the WCRC, based on the current WCRC standards for curb and gutter and shall be a MDOT Type ?L? opening unless otherwise authorized.

3.10.4

Residential driveway dimensions

1. The design feature dimensions of a residential driveway shall conform to those given in Table 7.

Table 7: Residential Driveway
Design Features		Curbed Roadway		Curbed Roadway
		Standard	Range	Standard	Range
Intersecting Angle	A	90°	80 to 100°	90°	80 to 100°
Driveway Width	B	12ft	10 to 20ft	12ft	10 to 20ft
Entering Radius	C	15ft	5 to 15ft	15ft	5 to 20ft
Exiting Radius	D	10ft	5 to 10ft	10ft	5 to 20ft
Curb Cut	R	26ft	20 to 40ft	Not Applicable

The standard shall be used unless engineering judgment determines that another dimension within the range is more suitable for a particular site or a special condition is approved by the WCRC.

3.11.1

The MDOT Geometric Design Guide, GEO-680 shall be used by the applicant in dimensioning a proposed commercial driveway or driveway system on plans accompanying the driveway permit application. The WCRC may specify certain dimensions so a particular driveway system will accommodate vehicle movements normally expected without creating undue congestion or hazard on the roadway or to provide reasonable access.

3.11.2

If the roadway carries one-way traffic, dimensions may be altered so that the prohibited movements are discouraged. If the driveway system is on the left-hand side of a one-way roadway, the dimensions used shall be based on the same principles as used on right-hand side driveways.

3.11.3

A divided commercial driveway shall have a curbed island separating the entrance and the exit drive. The radii forming the edges on this island shall be designed to accommodate the largest vehicle that will normally use the driveway. WCRC may deny divided commercial driveways in areas where left turn interlock problems may develop or where otherwise deemed necessary by WCRC.

3.11.4

To facilitate vehicle movements between a roadway and private property when the major vehicle movement at a commercial establishment is approximately parallel to the roadway, such as at a service station or drive-in bank, the WCRC may permit dual service driveways.

3.11.5

A directional commercial driveway is a special case and the driveway shall be designed individually to facilitate the desired turning movements and to discourage prohibited movements. Radii shall be as approved by the WCRC, based on the driveway intersecting angle and on the turning path of the largest vehicle that will normally use the driveway.

3.12.1

One farm field entrance may be permitted for each 1000 feet of frontage of cultivated land, timber land or undeveloped land. Additional driveways may be permitted when a single driveway will not provide adequate access due to topographic conditions.

3.12.2

Field entrances may be surfaced with stabilized gravel and may be uncurbed unless otherwise required by the WCRC.

3.12.3

The design feature dimensions of a farm field driveway shall conform to those given in Table 8 and as illustrated in Figure 2.

3.13.1

A utility structure driveway may be surfaced with stabilized gravel or with sod over a stable base and may be uncurbed, as determined by the WCRC.

3.13.2

The design feature dimensions of a utility structure driveway shall conform to those given in Table 9 and as illustrated in Figure 2.

The standard shall be used unless engineering judgment determines that another dimension within the range is more suitable for a particular site or a special condition is approved by the WCRC.

The standard shall be used unless engineering judgment determines that another dimension within the range is more suitable for a particular site or a special condition is approved by the WCRC.

Table 8: Farm Field Driveway
Design Features	Curbed Roadway	Uncurbed Roadway
		Standard	Range	Standard	Range
Intersecting Angle	A	90?	80 to 100?	90?	80 to 100?
Driveway Width	B	20 ft	15 to 40 ft	20 ft	15 to 40 ft
Entering Radius	C	Not Applicable		20 ft	5 to 40 ft
Exiting Radius	D	Not Applicable		20 ft	5 to 40 ft
Curb Cut	R	26 ft	20 to 50 ft	Not Applicable
Table 9: Utility Structure Driveway
Design Features	Curbed Roadway	Uncurbed Roadway
		Standard	Range	Standard	Range
Intersecting Angle	A	90?	80 to 100?	90?	80 to 100?
Driveway Width	B	20 ft	15 to 40 ft	20 ft	15 to 40 ft
Entering Radius	C	Not Applicable		20 ft	5 to 40 ft
Exiting Radius	D	Not Applicable		20 ft	5 to 40 ft
Curb Cut	R	26 ft	20 to 50 ft	Not Applicable

3.14.1

Driveways serving large developments frequently generate large numbers of turning movements. On two-lane, two-way roadways, this situation can disrupt traffic operations and often makes shoulder maintenance difficult. MDOT Traffic & Safety Notes 603A, 604A, and 605A shall be utilized in order to promote a uniform system to determine where right-turn lanes, left-turn lanes, or passing flares shall be required as a condition of permit issuance.

3.14.2

The applicant shall provide right-turn lanes or tapers as part of a commercial driveway system if the WCRC determines per MDOT standards or an approved traffic impact study that such right-turn lanes or tapers are required to minimize congestion or hazard on the roadway caused by vehicles entering the applicant's driveways. A right-turn lane shall be preceded by a taper. The current MDOT Design Guide for Flares and Intersection Details, VII-650 series, shall be utilized for the design of turning lanes, flares and tapers.

3.14.3

The cross slope of a right-turn lane and tapers shall be 2%, unless otherwise determined by the WCRC.

3.15.1

Residential driveways will normally be surfaced to match the existing road surface type, i.e., HMA if the existing road is HMA or PCC if the existing road is PCC. When required by the WCRC, residential driveway approaches shall be paved with HMA Mixture 13A, placed according to MDOT specifications using 330 lbs/syd minimum. Concrete driveway approaches shall use six inches minimum of PCC Grade P1. When reinforcement is specified, wire fabric reinforcement shall be used according to MDOT Standard Plan R-29 Series.

3.15.2

A commercial driveway shall be paved and curbed to the right-of-way line and shall be an MDOT Type ?M? opening unless otherwise authorized.

3.15.3

When the public road to be accessed is paved the type of surfacing at commercial driveways depends upon the existing surface of the road and the potential axle loading of vehicles using the driveway.

3.15.4

When the public road to be accessed is unpaved commercial driveways may be surfaced with stabilized gravel. The minimum requirement for commercial driveways is ten inches of compacted MDOT 23A dense-graded aggregate. If driveways are paved, the paving shall extend no closer to the road than one foot behind the driveway culvert location or five feet from the edge of the road, whichever is greater.

1. The surface of paved commercial driveways, including tapers without right-turn lanes, shall be concrete, hot mix asphalt or equivalent surfacing material. The thickness of the surface and the base to be used shall be sufficient to provide the bearing capacity needed to carry the proposed traffic loads. A three-inch (330 pounds per square yard) hot mix asphalt on eight inches of compacted gravel, or eight inches of hot mix asphalt on existing ground, or eight inches of nonreinforced concrete on sand, or equivalent surfacing material which meets current MDOT Standard Specifications For Construction may be considered acceptable for normal commercial driveway traffic loads over stable soil.
2. The pavement of all additional lanes such as turning lanes, and accompanying tapers, shall be the same material as the pavement of the existing road or applicable WCRC pavement cross section, whichever is greater. The cross slope of all additional lanes and all tapers shall be a continuation of the cross slope of the existing road pavement unless otherwise specified by the Permit Section.
3. The surface of road shoulder adjacent to all additional lanes and tapers shall be of the same material as the surface of the contiguous existing road shoulder and shall conform to the current MDOT Standard Specifications For Construction. The shoulder area between adjacent commercial driveways serving the same property which are less than 200 feet apart (centerline to centerline) must be paved as directed by the Permit Section.
4. If a roadway is uncurbed, the following driveway surfacing and curbing requirements apply:
   1. A commercial driveway, along a paved road, shall be paved and curbed either to the right-of-way line or to the point of curvature between the driveway edge and the larger radius, point b in Figure 1, except a commercial driveway may be uncurbed where there is a proper ditch and other adequate roadside control or delineation, as determined by the WCRC. The curb ending adjacent to the roadway shall be located at least 13.5 feet from and parallel to the edge of the pavement.
   2. A commercial driveway approach off a gravel road shall be gravel.

3.15.5

Surface materials and thickness

1. The surface of a paved driveway, excluding right-turn lanes, shall be concrete, bituminous or equivalent surfacing materials. The thickness of the surface and the base to be used shall be sufficient to provide the bearing capacity needed to carry the proposed traffic loads. A 2 ? inch, 250 pounds per square yard, bituminous mix on 8 inches of compacted gravel, 8 inches of unreinforced concrete or equivalent surfacing material, which meets the MDOT Standard Specifications for Construction, is acceptable for normal driveway traffic loads over stable soil.

3.16.1

Curbing shall either be the same detail as any existing curb or shall conform to the current WCRC standards for curb and gutter.

3.16.2

If the road is uncurbed, the grade of the driveway between the road edge of pavement and the edge of the shoulder shall conform to the slope of the shoulder.

3.16.3

The curb height shall be tapered from full height at the edge of pavement to zero-height at any sidewalk if the driveway grade meets the grade of the existing sidewalk.

3.16.4

The driveway curb shall either match the existing roadway curb or shall conform to the current WCRC standards for curb and gutter.

3.16.5

The driveway curb height shall be constant if there is no existing or proposed sidewalk or if an inclined sidewalk is permitted by the WCRC.

3.16.6

The driveway curb height may be tapered to zero height at the sidewalk if the driveway grade meets the grade of an existing or proposed sidewalk.

3.17.1

The surface of the shoulder adjacent to a right-turn lane and tapers shall be of the same materials as the roadway shoulder and conform to the MDOT Standard Specifications for Construction.

3.17.2

If the distance between two paved commercial driveways serving the same property is less than 200 feet, measured between adjacent ends of the curb endings, the applicant shall pave the shoulder between the driveways, unless otherwise determined by the WCRC.

3.18.1

Design of drainage facilities shall conform to the current edition of the MDOT Drainage Manual.

3.18.2

A driveway or road approach, including any new lanes or tapers, shall be constructed so that the existing drainage is not adversely affected. The drainage and the stability of the road subgrade shall not be altered by driveway construction or roadside development. Roadway drainage shall be carried to the outside edge of the pavement.

3.18.3

Drainage from adjacent private property in excess of assumed agricultural runoff from natural ground contours shall not be discharged directly into the road drainage system. Drainage from paved areas of the driveway within the right-of-way shall be directed outside the right-of-way unless adequate enclosed drainage facilities are available or are provided by the Applicant as part of the driveway construction.

3.18.4

All culvert pipe used shall be of a size adequate to carry the anticipated natural flow of the ditch. The culvert size shall be approved by the WCRC and shall be not less than 12 inches inside diameter. All culverts, catch basins, drainage channels and other drainage structures required within the road right-of-way shall be manufactured or constructed and installed in accordance with the current MDOT Standard Specifications For Construction. The minimum length of the culvert may be determined as the sum of the width of the driveway and the distance needed to provide slopes to adjacent fore slope and back slope with a maximum transverse slope of 1 on 6 for locations susceptible to high-speed impacts. On low-volume or low-speed roads, where a crash history does not indicate a high number of run-off-the-road occurrences, a steeper transverse slope up to 1 on 4 may be considered. The use of headwalls on culvert ends will not be permitted. The use of sloped end sections or mitered ends are required on all culverts 18 inches diameter and greater. Sod, rip-rap or other suitable material shall be placed at all culvert ends and slopes to prevent erosion.

3.19.1

If the road is curbed, the grade of the driveway shall meet the existing edge of pavement.

3.19.2

If the road is uncurbed, the grade of the driveway between the road edge of pavement and the outside edge of the shoulder shall conform to the slope of the shoulder. Where the existing shoulder is less than six feet, the grade of the existing road bed or shoulder shall be carried to a point six feet off the edge of the existing roadway surface.

3.19.3

The grade of two-way, one-way, and divided commercial driveways shall not exceed a maximum of six percent (6%).

3.19.4

The grade of residential, utility, and field driveways shall not exceed a maximum of ten percent (10%).

3.19.5

Vertical curves (15-foot minimum) shall be provided at all changes of grade of four percent (4%) or more.

3.19.6

If a sidewalk elevation must be adjusted to meet the driveway, the slope of the sidewalk shall not exceed five percent (5%).

3.19.7

A driveway profile shall be determined using the following criteria:

1. If the roadway is uncurbed, the grade of the driveway between the roadway edge of pavement and the edge of the shoulder shall conform to the slope of the shoulder.
2. If the roadway is uncurbed or if the sidewalk is more than 10 feet from the edge of the pavement or if there is no sidewalk:
3.  
   1. The grade of a two-way, one-way or divided commercial driveway after it transitions from the shoulder edge shall not exceed 6%.
   2. The grade of a residential or utility structure driveway or field entrance shall not exceed 10% after it transitions from the shoulder edge.
4. If the roadway is curbed and if the sidewalk is 10 feet or less from the edge of pavement, the grade of a driveway, except a directional driveway, shall be the grade required to meet the sidewalk elevation; but if that grade would exceed the maximums specified in paragraph (b), the sidewalk shall be either tilted or inclined.
5. The grade of a directional driveway shall be designed so to provide vision of the roadway edge of pavement and the driveway surface for a distance of 100 feet along the driveway. For a driveway on an upgrade towards the roadway, a grade of 1.5% for a distance of 100 feet from the edge of the pavement is acceptable. Beyond this distance, the grade shall not exceed 6% and the differences in grades where there is a change of grade shall not exceed 3%.
6. Vertical curves, with a minimum length of 15 feet, shall be provided at a change of grade of 4% or more.

3.20.1

Adequate storage for vehicles parking or waiting to be serviced shall be provided so as not to interfere with pedestrian movements, vision requirements or traffic operations on the roadway.

3.20.2

Commercial establishments of a "drive-in" nature (drive-in restaurants, drive-in banks, auto washes, etc.) should provide adequate storage off highway rights of way for vehicles waiting to be serviced because vehicle storage on highway lanes or shoulders may constitute a traffic hazard in the public roadway.

3.21.1

The Applicant shall provide and/or maintain traffic control devices as required by the WCRC and per the current MMUTCD. The plans shall illustrate and specify all required traffic control devices. For private road approaches, a private road sign package including a stop sign and road name panel is required and shall be paid for, per the WCRC fee schedule, by the Applicant. The private sign package will be fabricated, installed and maintained by the WCRC at the completion of the private road approach construction.

3.21.2

At high-volume intersections, traffic safety and operations may be enhanced by the installation of a traffic signal. Traffic signal warrants shall be determined by reference to a traffic impact study completed by the Applicant's engineer. The installation of a traffic signal shall require approval of the County Highway Engineer. Although the warrants for the installation of a traffic signal may be satisfied, the County Highway Engineer may determine that a traffic signal would be detrimental to coordinated traffic flow, result in undue delay, impair traffic operations, or impair traffic safety on the county road. In this case, a traffic signal shall not be installed. If authorized by the County Highway Engineer, the traffic signal shall be designed in accordance with the current WCRC, MDOT, and MMUTCD requirements.

3.21.3

All costs associated with a traffic signal installation necessitated by or approved in conjunction with any new or modified public road access shall be the sole responsibility of the Applicant. Prior to approval of an access facility with a traffic signal, the Applicant shall enter into a formal agreement with the WCRC. The agreement shall delineate the responsibilities of the WCRC and the responsibilities of the developer regarding the signal installation. The responsibilities of the developer shall include, without limitation, paying or causing to be paid all perpetual costs for the energy and maintenance of a traffic signal; paying or causing to be paid all costs for any future upgrading, revisions, modifications, and/or modernizations; providing the WCRC with indemnification; and such other provisions related to the traffic signal installation as the WCRC shall require. Ownership of the traffic signal shall remain with the WCRC. If a traffic signal is required to be a part of an interconnected traffic signal system, the developer shall be responsible for all costs associated with the interconnection, before or after the installation of the signal.

3.21.4

To facilitate progression of traffic in both directions at design speed through a system of traffic signals, spacing of signalized intersections of an arterial or major collector roadway with cross streets should be in multiples of at least one-quarter mile.

3.21.5

Signalization of driveways should only be considered if driveway traffic volumes or past crash experience warrants installation. With the approval of the County Highway Engineer, any warranted driveway signals may be located 600-700 feet from adjacent signals if the driveways served form "T" intersections. Four-legged signalized driveway intersections should be avoided unless they are least one-quarter mile from adjacent signals. Driveway signals should also be interconnected and coordinated with any other signals, either existing at the time the driveway signal is installed or added later, within 1,500 feet of the signalized driveway.

3.21.6

Outside the public road right-of-way, the Applicant should provide and properly maintain approved permanent traffic control signs and pavement markings as necessary for the proper operation of the driveway intersection. All signs and pavement markings should conform to the current MMUTCD. The plans shall indicate the signing and pavement markings required.

3.22.1

When the Application and its supporting data demonstrate that traffic, safety, and/or road maintenance impacts of the proposed project or modified use will require road improvements as a condition of permit approval, the Applicant may decide, as a business decision, to agree to fund the road improvements. In such case the WCRC may require that the agreement of the parties be expressed in a written Road Improvement Agreement subject to the approval of the Board of County Road Commissioners. The Road Improvement Agreement shall set forth all of the material terms of the parties? agreement. The Road Improvement Agreement shall require that the parties obtain a Declaratory Judgment from the Washtenaw County Circuit Court, finding and declaring that the Agreement is a valid, lawful, binding, and enforceable agreement pursuant to any and all provisions of the Michigan Constitution, statutes, and common law.

1. The need for road improvements shall be determined in accordance with the findings of a traffic impact study.
2. When road improvements are required as a condition of permit approval, the WCRC shall not issue the permit until all of the foregoing conditions have been met.
3. Should the Applicant decline to fund the road improvements necessitated by the impact of the Applicant's project, the application will be denied. The WCRC is without funds to expend on mitigation of the impacts on the public roads caused by new development or intensified use.