Proiect Obiectives and Results

Transcription

1 Pedestnan Project Award Application Montgomery County, Maryland May 28,2003 Design Standards for Pedestrian and Bicycle-Friendly, Environmentally Sensitive Roadways Proiect Obiectives and Results Montgomery County, Maryland has developed an innovative set of design standards for open section roadways with sidewalks and off-road bikepaths. These standards were prepared primarily for application in the environmentally sensitive watersheds throughout the County. Three design standards were prepared for low volume residential streets (Tertiary, Secondary, and Residential Primary classzfkations) and three design standards were prepared for Master Planned collector roadways (Master Planned Primary, 2-lane Arterial, and 4-lane Divided Arterial). Two landscaping design standards and a policy to allow waivers for closed section roads in environmentally sensitive watersheds were are also developed as part of this project. These standards are the product of an effort that balanced the competing goals and objectives of a diverse group of stakeholders. The acknowledged group of stakeholders included motorists, pedestrians, bicyclists, public agencies, the development community, private utility companies, and the future residents. Noteworthy features of these standards include:& locating the sidewalks and off-road bikepaths behind the side ditches -for maximum clear zones from potentially errant vehicles; improved water quality of runoff due to reduced impervious (roadway) surface area and the natural filtering action of the sodded shoulders and side ditches; maintaining consistent driveway (longitudinal grade) and sidewalk (cross) slopes to satisfy the Americans With Disabilities Act; uniform shoulder and ditch sections - dimensions and slopes determined based on the hierarchy of roadway classifications; preserving developmentaot yields through the use of Public Improvements Easements (in lieu of requiring additional right-of-way); and providing street tree species and locations to promote shading the pavement and grass surfaces, in locations relative to the roadway classifications, to reduce the temperature of stormwater runoff..' These design standards are the result of the efforts of a dedicated team of public professionals drawn from staff in the Maryland-National Capital Park & Planning Commission, the Montgomery County Department of Permitting Services, and this Department. The local development community, through their representatives in the Maryland National Capital Building Industry Association and the Montgomery County Road Code Committee also offered invaluable suggestions, prior to approval of these details. The underlying goals of this project have been achieved. As a result of the reduced runoff and improved water quality at the storm drain outfalls, the environmental impact of open section roadways is significantly less than that of a comparable classification closed section roadway. Pedestrians, bicyclists, and handicapped persons are provided a pleasant and safe environment. The shoulder and ditch side slopes are such that maintenance by the abutting homeowners and public works crews can be performed with relative ease. Plan approval and permit acquisition have been facilitated since the adoption of these standards. These standards have now gained the acceptance and support of the regulatory (planning, transportation, and environmental) agencies as well as the private development industry. These design standards are now available on the internet through the County's website:

2 Pedestrian Project Award Application Montgomery County, Maryland Design Standards for Pedestrian and Bicycle-Friendly, Environmentally Sensitive Roadways Analvsis of the Proiect s Historv, Challenges, and Solutions The ProblemNeed for the Promam In 1992, the Montgomery County Council adopted two pieces of legislation which were intended to result in the construction of more sidewalks in new residential, commercial, and industrial subdivisions. This legislation amended two sections of the Montgomery County Code: Chapter 49 (the Road Code ) and Chapter 50 ( Subdivision of Land ). Administration of these two Chapters today falls under the joint jurisdictions of the Montgomery County Planning Board, the County Department of Public Works & Transportation, and the Department of Permitting Services.. Bill No amended Chapter 49 to require the construction of sidewalks in new subdivisions. When it was originally introduced, the bill proposed the construction of sidewalks where the zoning resulted in minimum lot sizes of one acre or less. Since the County s design standards at the time allowed sidewalks only on roads constructed with curb and gutter, this proposal would have resulted in significant environmental impact. The proposals were subsequently reconsidered and modified. In the bill s adopted form, sidewalks are now required in residential developments where the subdivision zoning results in minimum lot sizes of 25,000 square feet or less. The bill generally precludes the construction of streets with curbs and gutters ( closed section streets) in environmentally sensitive watershed areas (as designated by the Maryland Department of the Environment) or any headwaters area (when designated as environmentally sensitive by the County Department of Environmental Protection)., Companion Ordinance No amended the Subdivision Ordinance to also require the construction of sidewalks in new residential, commercial, and industrial developments. This bill was intended to provide better connectivity between new and existing adjacent developments. The bill provides the Montgomery County Planning Board the authority to require developers to extend sidewalks a reasonable distance off-site to connect with another sidewalk or an (existing or proposed) bus stop or public facility. The bill also requires constructing sidewalks on new public streets and existing frontage roads. The need to construct sidewalks on public open section roadways (roads which use shoulders and side ditches to redirect stormwater runoff) created a dilemma for both the public and the private sectors: the then-adopted County roadway design standards did not include sidewalks on open section roads. As a result, there was no consistency in the locations where private consulting engineers proposed to construct the required sidewalks: some engmeers proposed locating the sidewalk in the shoulder area while others proposed it behind the side ditch. This situation necessitated site specific designs and delayed all construction plan approvals (even subdivision plans that were not directly. affected by this legislation, because they were remained in the review queue). The County had an obligation to develop new design standards to resolve that problem. 1

3 Pedestrian Project Award Application,\ Montgomery County, Maryland Description of the Proaam An all-volunteer team of public professionals was organized in early 1994, charged with the task of developing a set of recommended design standards. Six representatives (two from each of the three County agencies that were affected by the legislation) participated on the original team [agency representatives did change over time, as the project evolved from conceptual planning to design and implementation]. Each person was a specialist with either a transportation or an environmental background. Each team member had an equal vote in the team s discussions and was encouraged to consult with other staff in their agency. Because this team was composed entirely of volunteers, operating without a dedicated budget or schedule;.meetings were held on an infrequent basis - in large part to accommodate the team members official work assignments, priorities, and individual schedules. Team members were forced to think in an innovative manner, overcome their own individual biases and agendas, and cooperate with one another to achieve consensus. The team was also ubliged to balance the transportation and environmental criteria of the enabling legislation, as well as the oftencompeting goals of the previously identified group of stakeholders. Such considerations included: providing for safe passage by motorists, pedestrians, and bicyclists - commensurate with the roadway s classification and function; providing pedestrian facilities in accordance with the Americans With Disabilities Act (ADA); decreasing the volume of stormwater runoff by minimizing paved surface area; decreasing the temperature of stormwater runoff by shading paved surfaces and side ditches; maximizing the use of grass surfaces to naturally filter stormwater runoff of sediment, road salts, heavy metals, and organic materials and encouraging groundwater recharge; facilitating the design and approval of plans for roads, sidewalks, off-road bikepaths, and driveways; ensuring manageable construction costs for permittees and the County; preserving potential development yields through the use of Public Improvements Easements (for public facilities located outside the public rights-of-way); providing facilities which do not exacerbate public and/or private construction and maintenance costs; providing an aesthetically pleasing and readily-maintainable neighborhood for the future residents; and facilitating access to the private/public utility companies underground facilities. The team developed six typical sections based on the hierarchy of roadway classifications found in the County Road Code: tertiary, secondary, primary, and arterial. These typical sections were divided into two distinct groups: residential streets and master planned roads. The three residential street standards are for tertiary, secondary, and residential primary roadways. The three masterplanned roads standards are for the master planned primary and two arterial roadways. Residential streets are envisioned to be low volume, low speed roads on which their neighborhood character has been a significant consideration. These roadway classifications are determined during the subdivision review process. Enhancing the neighborhood character - by shading the street - is an important goal of the residential roadway sections. 2

4 Pedestrian Project Award Application Montgornely County, Maryland Description of the Program (cont.) Masterplanned roadways, on the other hand, are determined through the County s Master Plan process. These roads are expected to carry greater volumes of traffic - often at higher speeds - with little or no direct driveway access. As such, they are intended to facilitate the through movement of vehicular traffic. They are also those roadways on which bicycle facilities are most often located. For those reasons, the team chose to emphasize vehicular and bicyclist safety on the master planned road sections. The team was challenged by five major issues. Those issues were: A. widths of rights-of-way versus perpetual easements; B. location and species of street trees; C. location, width, and material of the sidewalk and bikepaths; and D. identification of the optimum dimensions and slopes of the shoulder, ditch, and driveway; and E. criteria to allow closed section streets in environmentally sensitive watersheds on nzn-ow frontage lots. A. Widths of rights-of-wav versus perpetual easements: The County s standard rights-of-way are not sufficient to accommodate all of the required improvements. As a result, the team evaluated the desirability of wider right-of-way widths versus the use of perpetual easements. Wider rights-of-way were not favored for several reasons: greater out-to-out setbacks between opposing houses, potential additional encroachment on any environmentally sensitive areas behind the proposed homes, and reduced development yields. Consequently, the team advocated the use of Public Improvements Easements (PIES) to allow sidewalks and off-road bikepaths to be constructed and publicly maintained on private property. Public Utility Easements are also proposed to overlap the PIES as necessary to provide the utility companies ten (10) feet of unencumbered work area. B. Location and species of street trees: Street tree locations are a critical component of these typical sections. Heretofore, the County s standards reflected street tree locations (on open section roads) only behind the side ditch, The team wanted to promote the environmental benefit which will result from shading the pavement and grass areas while still providing a reasonable balance between environmental sensitivity, safety, and aesthetics. County arborists aided the team by recommending a list of deciduous tree species based on their root growth and branching characteristics. To reinforce the concept of a hierarchy of roadway classifications, the location of street trees varies within the different sections. On the residential streets, street trees are proposed to be planted in front of or within the side ditch - to maximize the shading benefit and enhance the neighborhood character. The separation between the edge of the roadway and the street tree differs relative to, the hierarchy of roadway classifications. On the master planned roadways, where safety is promoted by providing a clear (horizontal) zone from vehicles, street trees are proposed behind the side ditch in accordance with the previously adopted standards. Since these three standards allow street trees to be planted within three (3) feet of the sidewalk and the off-road bikepath, root barriers are to be provided to protect those paved surfaces fiom damage by the nearby trees. 3

5 Pedestrian Project Award Application Montgomery County, Maryland Description of the Promam (cont.) C. D. E. Location, width, and material of the sidewalk and bikepaths: Each of the approved standards locates the sidewalk behind the side ditch. This location was determined to be the optimal location for several reasons including safety, constructability, aesthetics, and maintenance. A four (4)-fOOt wide sidewalk was approved for the tertiary and secondary streets while a five (5) foot wide sidewalk was approved on the primary and arterial roadways. An eight (8) foot wide off-road bikepath is shown behind the side ditch on the primary and arterial standards. On the two arterial roadway sections, the roadway shoulder is paved only four (4) feet wide [instead of our current standard of eight (8) feet] to minimize impervious surface area; this area is available for use by on-street bicyclists.._ The originally approved standards reflected the use of bituminous concrete dnveways, sidewalks, and bikepaths. However, to facilitate the long-term maintenance of the sidewalks, the material was amended to portland cement concrete on the July 1 1,2000 standards. At the request of the development community, it was agreed that the driveway apron may be constructed using concrete or asphalt, at the discretion of the developer. Identification of the optimum dimensions and slopes of the shoulder, ditch, and driveway: In order to maintain adequate cover over the dnveway culverts and satisfy the ADA-mandated two (2) percent cross-slope across the sidewalk, a number of alternatives were analyzed. In the end, it was decided to employ a single uniform cross-section for each standard. These uniform crosssections, which will facilitate plan approvals as well as future roadway and driveway construction, neces-sitated modifications to the County s typical dimensions and slopes on the shoulder and side ditch. Roadway classification and function were considered in determining the extent of these adjustments. Criteria to allow closed section streets in environmentallv sensitive watersheds on narrow frontage lots: During the development of these standards, the development community advised the team that open section residential streets would be undesirable on streets bordered by narrow frontage lots. It was agreed that criteria needed to be developed to allow the automatic approval of closed section roads along such lots, without the requirement of a formal waiver request. The team s recommen-dations have been approved. In general, streets with lots averaging eighty (80) feet or less may auto-matically be designed as closed section roads, with the construction of additional water quality measures. Lots averaging one hundred (100) feet or more should be designed as open section roads. Streets with average lot frontages in the eighty (80) to one hundred (100) foot range require a site specific justification and approval. Conclusions The underlying goals of this project have been achieved. As a result of the reduced runoff and improved water quality at the storm drain outfalls, the environmental impact of open section roadways is significantly less than that of a comparable classification closed section roadway. Pedestrians, bicyclists, and handicapped persons are provided a pleasant and safe environment. The shoulder and ditch side slopes are such that maintenance by the abutting homeowners and public works crews can be performed with relative ease. Plan approval and permit acquisition have been facilitated since the adoption of these standards. These standards have now gained the acceptance and support of the regulatory (planning, transportation, and environmental) agencies as well as the private development industry. These design standards are now available on the internet through the County s website: 4

6 TYPICAL ROAD SECTION '4. CONCRETE 6' AT DRNEWAYS._ PAVING SECTION 3" BITUMINOUS CONCRETE BASE COURSE 1 APPROVED SUBGRADE I GENERAL NOTES REFER TO MARYLAND 'STATE HIGHWAY ADMINISTRATION SPECIFICATIONS FOR MATERIALS AND ME~HODS OF CONSTRUCTION. SEE STANDARD NO. MC METHODS OF GRADING SIDE SLOPES. PUBLIC UTlLlM EASEMENTS (PUEs) ARE SUBJECT TO THE TERMS AND CONDITIONS OF A DOCUMENT ENTITLED "DECLARATIONS OF TERMS AND PROVISIONS OF PUBLIC UTlLlM EASEMENTS" THAT IS RECORDED IN THE LAND RECORDS OF MONTGOMERY COUNTY IN LIBER 3834 AT FOLIO 457. THE SIDE DITCH IN FILL SLOPES MAY BE ELIMINATED IN AREAS NOT MASTER PLANNED FOR DEVELOPMENT ONLY AFTER OVERLAND FLOW PATH AND EROSION POTENTIAL ARE CONSIDERED. SEE STANDARDS NO. MC AND MC FOR SPECIES, SIZE AND SPACING OF STREET TREES. WHEN USING THIS STANDARD, THE GARAGE SHALL BE SET BACK A MINIMUM DISTANCE OF 20 FEET, MEASURED FROM THE BACK EDGE OF THE SIDEWALK. THE MINIMUM BUILDING RESTRICTION LINE SETBACK IS 25 FEET. STREET LIGHTING POLES ARE TO BE LOCATED AS DIRECTED BY THE MONTGOMERY COUNTY DEPARTMENT OF PUBLIC WORKS AND TRANSPORTATION. PUBLIC IMPROVEMENTS EASEMENTS (PIES) ARE TO BE GRANTED BY A SITE SPECIFIC DECLARATION OF PUBLIC IMPROVEMENTS EASEMENT DOCUMENT. THAT DOCUMENT IS TO BE RECORDED IN THE LAND RECORDS OF MONTGOMERY COUNTY, MARYLAND AND REFERENCED ON THE RECORD PLAT. THE 2-FOOT WIDE SECTION OF THE PIES BEHIND THE SIDEWALKS IS TO ALLOW FOR THE TEMPORARY CONSTRUCTION, RECONSTRUCTION, AND MAINTENANCE OF THE SIDEWALKS. NO PERMANENT PUBLIC IMPROVEMENTS ARE TO BE PLACED WITHIN THESE 2-FOOT WIDE STRIPS. SEVERAL OF THE DIMENSIONS SPECIFIED ON THIS STANDARD REFLECT MODIFICATIONS TO THE VALUES SHOWN ON STANDARD NO. MC (RESIDENTIAL DRIVEWAY/OPEN SECTION ROAD). ELEVATION AT THE FRONT EDGE OF SIDEWALK = EDGE OF PAVEMENT ELEVATION ' APPROVED STANDARD NO. MC

7 TYPICAL ROAD SECTION 4'-0' SHOULDER 'w Li 2 $1._ 1/2' BITUMiNi BITUMINOUS cconcrete o i n SURFACE BASE COURSE ioutm. 6' AT DRIVEWAYS CLASS I BIKEPATH (SEE NOTE 14) STD. Mc ~ TYPE A PAVING SECTIONS?!I 4" CONCRETE 6' AT DRIVEWAYS, I 3" BITUMINOUS CONCRETE SURFACE COURSE IN 2-1 1/2" LAYERS 5." BITUMINOUS CONCRETE BASE 8" GRADED AGGREGATE BASE I 9" BITUMINOUS CONCRETE BASE COURSE IN 2-4 1/2" LAYERS SUBGRADE DRAINS REQUIRED SEE MC PREFERRED GENERAL I APPROVED SUBGRADE 1 NOTES ALTERNATE REFER TO MARYLAND STATE HIGHWAY ADMINISTRATION SPECIFICATIONS FOR MATERIALS AND METHODS OF CONSTRUCTION. SEE STANDARD NO. MC METHODS OF GRADING SIDE SLOPES. PUBLIC unm EASEMENTS (PUE~) ARE SUBJECT TO THE TERMS AND CONDITIONS OF A DOCUMENT ENTITLED "DECLARATIONS OF TERMS AND PROVISIONS OF PUBLIC UTILITY EASEMENTS" THAT IS RECORDED IN THE LAND RECORDS OF MONTGOMERY COUNTY IN UBER 3834 AT FOLIO 457. THE SIDE DITCH IN FILL SLOPES MAY BE ELIMINATED IN AREAS NOT MASTER PLANNED FOR DEVELOPMENT ONLY AFER OVERLAND FLOW PAM AND EROSION POTENTIAL ARE CONSIDERED. A PHYSICAL ROOT BARRIER SHALL BE PROVIDED WHERE STREET TREES ARE CLOSER THAN SIX FEET TO A SIDEWALK OR BIKEPATH. MINIMUM DEPTH OF ROOT BARRIER SHALL BE EIGHTEEN INCHES. ROOT BARRIER SHALL EXTEND A MINIMUM DISTANCE OF 10 FEET LONGITUDINALLY ON EITHER SIDE OF THE TREE. SEE'STANDARDS NO. MC AND MC FOR SPECIES, SIZE AND SPACING OF STREET TREES. WHEN USING THIS STANDARD, THE GARAGE SHALL BE SET BACK A MINIMUM DISTANCE OF 20 FEET, MEASURED FROM THE BACK EDGE OF THE SIDEWALK (OR BIKEPATH, AS APPROPRIATE). STREET LIGHTING POLES ARE TO BE LOCATED AS DIRECTED BY THE MONTGOMERY COUNTY DEPARTMENT OF PUBLIC WORKS AND TRANSPORTATION. PUBLIC IMPROVEMENTS EASEMENTS (PIES) ARE TO BE GRANTED BY A SITE SPECIFIC DECLARATION OF PUBLIC IMPROVEMENTS EASEMENT DOCUMENT. MAT DOCUMENT IS TO BE RECORDED IN THE LAND RECORDS OF MONTGOMERY COUNM. MARYLAND AND REFERENCED ON THE RECORD PLAT. THE 2-FOOT WIDE SECTIONS OF THE PIES BEHIND THE SIDEWALK/BIKEPATH ARE TO ALLOW FOR THE CONSTRUCTION, RECONSTRUCTION, AND MAINTENANCE OF THE SIDEWALKS AND BIKEPATH (AND THE INSTALLATION OF STREETLIGHTING BEHIND THE SIDEWALK AND/OR THE BIKEPATH, IF REQUIRED BY THE DIVISION TRAFFIC AND PARKING SERVICES). SEVERAL OF THE DIMENSIONS SPECIFIED ON THIS STANDARD REFLECT MODIFICATIONS TO THE VALUES SHOWN ON STANDARD NO. MC (RESIDENTIAL DRIVEWAY/OPEN SECTION ROAD). DRIVEWAY WILL BE CONSIDERED ON A CASE BY CASE BASIS BUT ARE NOT TO BE ENCOURAGED ON ARTERIAL ROADWAYS. DRIVEWAY PIPES LARGER THAN 15" x 21" MAY NOT BE USED WITH THIS STANDARD. ELEVATION AT THE FRONT EDGE OF SIDEWALK/BIKEPATH - OUTSIDE EDGE OF PAVED SHOULDER ELEVATION ' BIKEPATH WILL BE REOUIRED ONLY IF SPECIFIED IN THE MASTER PLAN OR IF INCLUDED AS A CONDITION OF SUEDNlSlQN APPROVAL. '. REVISED MONTGOMERY COUNTY DEPARTMENT DIRECTOR, U6Wr -- \ + U ARTERIAL DUAL ROAD OPEN SECTION WITH SIDEWALK H BIKEPATH. AND STREET TREES I I I=I STANDARD NO. MC

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