2701 Prospect ▪ PO Box 201001 Helena MT 59620-1001 Christopher Dorrington, Director

To:	Ryan Dahlke, P.E. Statewide Project Development Engineer

From:	Insert name of individual submitting request Insert title of individual submitting request Insert name of Agency submitting request

Date:	Date Submitted to MDT

Subject:	Insert Project Name Local Agency Name (i.e. City of Bozeman) Request for Exception to Design Standards

Executive Summary

The executive summary should describe what you are seeking for a design exception. Provide a brief description of the features that will require an exception to approved design standards.

Example:

The City of Bozeman is developing a project for improvements on an MDT facility, and is requesting an exception to MDT design criteria, specifically for objects within the clear zone. As described further in this report, the City is proposing to install 8 trees, 4 bike racks, and 5 non-breakaway luminaires. While these elements are more than 1.5 feet behind the curb, they do lie within the clear zone for this facility.

Proposed Project

This section should describe the proposed project. Describe general project information, including the purpose and need, location, length, and scope of work. Provide a brief description of the proposed design features of the project (i.e. horizontal and vertical curve discussion, number and widths of travel lanes, parking lanes, shoulders, curb & gutter, as well as other miscellaneous elements like lighting, landscaping, and signing).

Example:

This project is located on North 7th Avenue, from West Mendenhall Street to Beall Street. The purpose and need of the project is to improve non-motorized facilities and to enhance aesthetics of the corridor. This will be accomplished by adding boulevard and sidewalk, bike racks, trees, and period lighting. No changes to the existing roadway driving surface will be made. The roadway horizontal and vertical alignments, width and number of travel lanes and shoulders, surfacing, striping, and drainage elements will all remain in their existing condition. Minor modifications to the curb and gutter to occur are limited to curb returns where ADA ramps are being brought into compliance and at driveway replacements as necessary to complete the work.

Existing Conditions

This section should address the existing conditions in which the project is being proposed and provide the context to better understand the potential impact of the design exception. Include:

Functional classification

Posted speed limits

Traffic data (current AADT and percent trucks) (available on MDT’s internet site)

Use and character of land adjacent to the project

Planned or anticipated changes in adjacent land use

Example:

This section of North 7th Avenue is classified as an urban principal arterial with a posted speed limit of 25 mph through the extent of the project limits. According to MDT’s Traffic Data interactive GIS map, this section of roadway has a 2017 AADT range of 10,175 – 14,798. There is a specific Short Term Count Site located just north of W Mendenhall Street that falls within the limits of this project. That Traffic Count Site indicates a specific 2017 AADT of 14,478. Adjacent land use and character is highly developed with a mix of residential and commercial use, and there is no foreseeable or planned changes in use or zoning.

Description of Design Exception and Applicable Criteria

This section should address the design exception in detail. In the case that there are multiple design exceptions being submitted, each design exception request should be individually addressed. Include:

A detailed explanation of the design exception and why it is the preferred action, particularly why it is appropriate and consistent with the purpose and need of the project.

A quantitative comparison of each controlling element standard to the proposed element for which the design exception is being sought. Provide measurable and meaningful dimensions and/or frequency of the proposed design exception element with respect to the overall project.

Example:

Throughout the limits of the project, numerous obstructions are proposed that fall within the limits of the clear zone. These items are specified in the table below. The clear zone was obtained from the MDT Road Design Manual, Exhibit 9-1, using a design speed of less than 40 mph, a design ADT of over 6,000, and a slope flatter than 6:1.

Item	Construction Plan CL Station; Offset	Offset from edge of travel lane	Offset from face of curb	Clear zone width
Luminaire	5+72.3, 29.9’ LT	6.8’	3.4’	14’
Luminaire	6+07.9, 32.8’ RT	6.6’	3.3’	14’
Luminaire	7+26.7, 33.2’ RT	6.6’	3.2’	14’
Luminaire	8+43.2, 36.6’ RT	9.4’	6.5’	14’
Luminaire	10+02.8, 36.4’ RT	8.9’	6.4’	14’
Tree	4+77.7, 30.9’ LT	7.3’	3.9’	14’
Tree	5+14.5, 32.6’ RT	6.7’	3.5’	14’
Tree	5+14.6, 30.6’ LT	7.5’	3.9’	14’
Tree	5+61.2, 32.8’ RT	6.8’	3.5’	14’
Tree	6+20.3, 30.0 LT	7.1’	3.8’	14’
Tree	7+22.7, 29.5’ LT	6.0’	3.5’	14’
Tree	8+38.4, 29.4’ LT	5.6’	3.6’	14’
Tree	9+49.3, 29.5’ LT	5.1’	3.5’	14’
Bike Rack	4+69.7, 30.8 LT	7.2’	3.8’	14’
Bike Rack	5+30.8, 32.4’ RT	6.4’	3.3’	14’
Bike Rack	8+55.1, 28.8’ LT	5.1’	3.0’	14’
Bike Rack	9+71.7, 29.2’ LT	4.8’	3.2’	14’

These items are non-breakaway, non-crash tested elements, and therefore are considered obstacles in the clear zone. Since the purpose and need of the project is to improve non-motorized facilities and to enhance aesthetics of the corridor, the inclusion of these elements serves the purpose and need of the project. Quantitatively speaking, there are a total of 17 point-obstacles in the overall length of the project, which is 600 feet.

Impacts to Safety and Operational Performance

This section should address the safety and operational impacts. If multiple design exceptions are being submitted, describe how the multiple design exceptions relate to one another directly or indirectly, particularly if there is a cumulative effect. Include:

A comparison of the safety and operational performance of the roadway with and without the proposed design exception elements.

A discussion of compatibility with adjacent roadway sections and anticipated future corridor improvements, including impact to driver expectancy.

A discussion on any other applicable impacts, such as right-of-way, community, environmental, cost, and usability by all modes of transportation.

The Highway Safety Manual (HSM) procedures may be used, when applicable, to compare predicted safety for alternative scenarios using level-of-service of safety.

Example:

There are limited safety or operational impacts to the roadway from this design exception. These obstacles will be located behind curb and gutter. While there are additional obstacles introduced to the roadside with this project, these types of items are expected in an urban setting. The described features are consistent with adjacent sections of roadway, as there are existing non-breakaway luminaires within the clear zone. There are no known anticipated corridor improvements adjacent to this project. The obstructions listed are expected conditions for this urbanized strip development.

Alternatives Considered

This section should include a description and explanation of any feasible alternatives that were considered and the reasons why the proposed treatment/element was selected.

Example:

Several alternatives to the proposed design were considered. One alternative would be to install the elements beyond the clear zone. This was removed from consideration due to site constraints. The existing right-of-way for North Seventh Avenue is located, in general, approximately 5’ behind the back of the existing curb. Additional right-of-way does not exist for the corridor, and it is well beyond the scope of work of this project to acquire additional right-of-way.

A second alternative typically considered related to obstructions in clear zones is to protect the element with roadside barrier. This is not a feasible alternative in this case due to the presence of on-street parking. Based on MDT crash data, there is not a demonstrated fixed object crash rate history for this low speed roadway that would indicate a trend requiring additional mitigation.

Lastly, designing the elements to be breakaway was considered. For the trees, that would involve limiting the tree species to those that have a mature trunk diameter of less than 4”. This was removed from consideration (explain why……). There are no known breakaway bike racks commercially, so this alternative was removed from further consideration for these elements. Regarding the luminaires, non-breakaway luminaires was requested by MDT per standard practice. MDT has determined the risk of breakaway luminaires falling on individuals is greater than the risk of injury if a non-breakaway luminaire is struck, particularly in low-speed environments such as this.

Mitigation Measures

This section should address any mitigation features proposed within the design, whether incidental or added exclusively to mitigate the non-conforming element. The FHWA document, Mitigation Strategies for Design Exceptions may be a resource; it provides potential mitigation measures for various design elements.

No feasible mitigation measures were identified. Potential mitigation measures that were evaluated include widening of the shoulder and signage/object delineation. Widening of the shoulder is well beyond the scope of this project. Additional signage or object delineation was eliminated from further consideration to avoid further inundation of signage in this urban area. As discussed in this request, the proposed elements fit within the context of the roadway and follow the practices described in the MDT Road Design Manual concerning objects in urban, curbed facilities.

Graphical representation (attached)

Provide attachments illustrating the design exception, such as plan view, profile view, cross-sections, and details, as available. Elements for which the design exception is being sought should be highlighted in some manner (i.e. circled in red, highlighted in some manner, etc.)

Concur:	Date:
Ryan Dahlke
Statewide Project Development Engineer

copies:

Choose District Administrator. District Administrator	Ryan Dahlke, Statewide Project Development Engineer
Dave Holien, Highways Engineer	Jon Swartz, Asset Strategy, Operations & Maintenance Mgr.
Andy Cullison, Bridge Engineer	Gabe Priebe, Traffic and Safety Engineer
LeRoy Wosoba, System Impact Supervisor Ed Ereth, Asset Strategy Program Manager	Doug McBroom, Statewide Planning & Modal Operations Mgr. Steve Felix, Maintenance Division Administrator