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HomeMy WebLinkAboutCOM 0227.008 1996-1998 Q~Ar,nrvV ~'l Eari Blumenauer, Commissioner C~ OF Fsgineering & Development 1120 S.W.Fihh Avenue = PORTI.AI`ID, OREGOI`I Portland, Oregon 97204-191 ' OFFICE OF TRANSPORTATIOf~1 (503) 823 7004 ~,asi - FAX: (503)823-7371 r RECEN® ''1'- n~.------------ ----pY- Data-----~ ~i.9.- -~-7 - Count' Council~P- ~'c REPORT ON NEW STANDARDS roR RESIDENTIAL STREETS IN PORTLAND, OREGON Terrence L. Bray, P.E. Karen Carlson Rabiner, P.E. Bureau of Transportation Engineering October 18, 1991 (Revised August 1, 1994) n. ltk~ suQ ~ - Ite~ ,~~Presented Pc- ~ ter, ~ JUL 2 s -1991 INTRODUCCION Over the past ninety years, it has been Portland's policy to provide maintenance services on only those local streets built to city standards. Those standards were developed to ensure that streets accepted Cor city maintenance meet necessary safety and durability crquirements. Streets in new subdivisions and other raw land developments are built to city standards at the expense of the developers, who then pass the cost along to new home buyers. Construction of city streets in existing neighborhoods has been accomplished through the city-managed Local Improvement District program, with the costs being assessed upon the adjacent, benefitting properties. Of the approximately 1200 miles of local streets in Portland, virtually all were improved through these two approaches. In Portland today, only about 80 miles oC public rights of way used as neighborhood streets remain unimproved. Many of the residents of these neighborhoods feel that the city offers too few improvement options, that the street standards are excessive, and that streets built to these standards are too costly. Added to those concerns is growing public dissatisfaction with high trafl-ic speeds and volumes on streets already improved to city standards. Street drainage, erosion control and water pollution issues have emerged in the Tualatin River Basin, and are a growing concern across the city. In 1988, a citizens committee was created to look at and seazch for solutions to the problems associated with unimproved neighborhood streets. Through the committee, a consultant was retained to "brainstorm" new solutions to traditional neighborhood street problems. At the suggestion o£ the consultant, the committee recommended that the city . develop new standards for city-maintained residential streets. In May 1990, the city began development of new standards for city-maintained residential streets. This report summarizes the development of those new residential street standards. The standards were adopted by the Portland City Council on July 31, 1991. 2 s ~ a. ~ DEVELOPMENT OF S'I'ANDAItDS In a report prepared by the consulting firm of Cogan Sharpe Cogan, it was recommended that City staff "...begin the effort to establish a performance evaluation approach to determine appropriate street improvement standards, while remaining acceptable for maintenance." Within the body of literature pertaining to the role of the neighborhood street and its impacts on the surrounding environment, the 1980 Bucks County, Pennsylvania publication, Performance Streets, reflected a new and substantially different view of the purposes of the various elements of residential street design. That document states: "Whether street standards were intuitively based or adapted jrom highway design, what seemed to have been overlooked was that focal residential streets are part and parcel of the neighborhood they serve. People live on them. It would seem desirable, therefore, not solely to moue lra~c safely and ejjuiently, but to see that the needs ojpeople for a residential neighborhood that is quiet, safe, pleasant, convenient and sociable are met as well." In 1990, the National Association of Home Builders, the Urban Land Institute, and the American Society of Civil Engineers joined to publish another milestone in urban street design, Residential Streets, which advocates: • designing to minimize traffic volumes and speeds in residential areas • properly scaled streets • streets planned to avoid excessive stormwater runoff • streets which can serve as meeting places and centers of community activity The philosophies espoused in both documents are clearly shared by many Portlanders. The challenge was to find a way to bring them to reality in Portland. The citizens committee's recommendation to develop performance standards was the beginning. The City retained a consultant to research the existing standards of several other communities for purposes of comparison, and then to propose new performance-based standards in an interim report. Transportation could then evaluate and refine those standards, secure public comment, and modify them as needed, before Seal City Council approval of implementation. In March 1991, the rnnsultaat completed the required interim report. Below are the consultant's key suggestions, followed by Transportation s recommendations. 1. Allow additional street width variations. Response: Transportation concurs with this recommendation. The city's existing neighborhood street standards are designed primarily 8H a traffic facility comprised of two travel lanes, plus either two parking lanes, one parking lane, or no parking, yielding widths of 82, 28, or 20 feet, respectively. Transportation proposes (a) reducsng the current 32-foot standard to 26 feet, and (b) reducing the current 28-foot standard to 20 feet. 3 The problems of high speeds and through, non-neighborhood traffic have been the source of continuing complaints from throughout the community. Streets designed to ealsting standards accommodate or encourage higher travel speeds. By virtue of the appearance of the 28 or 32-Coot streets as wide, inviting thoroughfares, they may also be used as a shortcut by non-neighborhood traffic. In addition to being considered costly to construct, the existing standards produce excessive stormwater runoff; require wide rights of way, are wasteful of natural resources, and demand clearing of many trees and other vegetation. An approach which reduces all of these problems, and one advocated in the publication Residential Streets, is building narrower streets with only a single travel lane. These "queueing streets", intended for two-way traffic, are comprised of a single traffic lane and a parking lane on one or both sides. When two vehicles meet on a queueing street, one of the vehicles must yield by pulling over into a vacant segment of the adjacent parking lane. (Of interest is the fact that many of the city's older local streets range from 18 to 28 feet wide and, as such, are queueing streets.) Acceptable operation of a queueing street occurs only where there are occasional breaks in the curbside parking approximately forty feet in length to permit the yielding vehicle to pull over. These breaks are ordinarily available where ample ofT street parking for residents is available, and where on-street parking by residents or guests is only occasional. Breaks in parking are also provided by individual driveways, combinations of driveways, and intersections. These conditions are commonly satisfied in areas Comprehensive Plan zoned Single Dwelling residential, t35 (5000 sq.ft. per dwelling unit) through RF (2 acres per dwelling unit). In more densely-zoned areas, queueing streets may be inappropriate because of inadequate off-street parking capacity, or because of differing emergency response requirements. The city currently requires all streets in new subdivisions to be built to accommodate on-street parking. The aty requires through streets to be 32 feet wide, which permits two travel lanes plus on-street parking on both sides of the sheet. For either cul-de-sacs, or streets serving 30 or fewer dwellings, or one-way streets, the required dimension is 28 feet, which permits two travel lanes and a parking lane on one side only. It is proposed that through streets be built with a single travel lane with parting on one or both sides, for widths of 20 or 26 feet, respectively. It is also recommended that the decision to provide a street with two-side versus one-side parting be at the discretion of the developer of the subdivision or of the property owners funding construction of the street. The proposal to reduce the widths of through streets differs firom that for cut-de- sacs, where it is proposed that the 20 and 26-foot widths be permitted to be further reduced to 18 and 24 feet, respectively. The two foot reduction, termed the "cut-de-sac compromise", would be constructed only if requested by those funding the street improvement. Although the additional two foot reduction in travel lane width reduces impervious surfaces and saves natural resources, it also further reduces the ease of operation between adjacent parked and moving 4 vehicles. Because a cul-de-sac serves only Uiose who are directly accessed by it, Lhe t«~o foot reduction may be a desirable element for those residing on the street. Because the site oC a fire emergency can be accessed from either direction on a through street, the Portland Fire Bureau has endorsed the proposed reduced street widths for through streets, but cul-de-sac streets present a problem for fire fighting operations. Hydrants are normally located at the intersection, and the first fire apparatus responding to an emergency pauses to connect its hoses to that hydrant. The truck then moves up the street, with the hose being drawn out from the rear, "snaking" out over the lane. If the street is narrow enough for only a single travel lane, such as with a queueing street, the second apparatus would have to drive over the charged hoses, risking greater damage or injury. Instead, on "short" cul-de-sacs, the second vehicle will park at the intersection and needed equipment can be carried to the scene by the firefighters. On longer cul-de-sac streets, fire fighting capabilities may be seriously compromised if all equipment must be hand-tamed to the emergency scene from the second or third apparatus. In addition, long, tightly curved, narrow cul-de- sacs with on-street parking may be physically inaccessible to fire apparatus. For that reason, except with the Fire Bureau Chiefs approval of measures designed to facilitate fire protection capabilities, it is proposed that newly-platted cul-de- sacs greater than 300-feet in length be built as a "fire lane", with two unobstructed travel lanes and, if needed, additional parking lanes. It is proposed that curbs be required, except where unsuitable or inappropriate, on all through streets. Curbs are used on city streets to a) facilitate sidewalk construction, b) confine vehicles to the roadway, c) control on-street parking, d) protect adjacent landscaping, e) channel street drainage, and f) accommodate roof drains. Circumstances under which curbs may be omitted may include, for example, where roadside drainage swales are necessary for water quality control purposes, or where city-adopted neighborhood plans provide the framework and rationale for uncurbed "lane" treatments. 2. Allow right of way widths to coincide with street widths. Response: Transportation concurs with this recommendation, and proposes reduang the right of way widths required for queueing streets in Comprehensive Plan Single Dwelling residential zones R7, R10, R20 and RF. Retain sufficient right of way width in zone R5 to accommodate the potential of sidewalk/planting strip construction on both sides of the street. Dedication of rights of way greatly in excess of those needed to accommodate specific street widths is costly and unreasonable. Proposed right of way widths are shown on page 8. These reduced widths permit greater utilization of privately-developable land, while maintaining sufficient space for utility installations and sidewalks. 5 ' 3. Allow reduced dead-end street turnaround sizes. Response: Transportation concurs with this recommendation, and proposes adoption oC a reduced diameter oC 70 feet Cor all newly-platted dead-end streets. The current standard diameter of all dead-end street turnarounds is 90 feet, and was originally developed to allow the largest fire apparatus to turn around without requiring a backing manuever. According to Residential Streets. "vehicle types that rarely use the street should not be a determining factor in the design. When weighed against the disadvantages oC an extensive paved area -poor aesthetics, higher maintenance and installation costs, increased stormwater runoff, and the significant limits that large dimensional requirements place on sound land planning -the minor inconvenience experienced by some drivers in reversing direction is not an important consideration." Bucks County's Performance Streets states "Cul-de-sac turnarounds should be designed no larger than necessary to permit free turning of the largest service vehicles regularly servicing the neighborhood." 4. Allow mountable curbs to be used in turnaround areas. Response: Transportation concurs with this recommendation. Once homes are built on the property adjacent to a cul-de-sac, the majority of the curb line within-the cul-de-sac is occupied by driveways. Permitting mountable curb to be constructed at the time of initial construction of the cul-de-sac will preclude the need to tear out and replace the curbing with driveway approaches. Mountable curbs are not permitted elsewhere because they a) permit and may encourage easy vehicular access to the front yard area of a residence, in conflict with city planning regulations, and b) permit easy vehicular access to the sidewalk area, which can cause sidewalk damage for which the property owner is liable. 5. Reduce minimum required separated sidewalk width to four feet. Response: Transportation concurs with this recommendation, but only in comprehensive plan Single Dwelling zones R7, R10, R20 and RF. The current minimum required width of a sidewalk in a residential area is five feet. Where a sidewalk is built adjacent to the curb without an intervening planting strip, pedestrians are forced to share the sidewalk with utility poles, signs, mail boxes, etc. A five-foot width is needed to provide space for pedestrian use around those obstacles. Where a sidewalk is built separate from the curb, the sidewalk is act similarly obstructed, and afour-foot width is sufficient for low volume pedestrian useage found in low density areas R7 through RF. 6 RECOMMENDED SI'ANllARDS:(Adopted by Portland City Council July 31, 1991) A. In Comprehensive Plan Single Dwelling zone R5 (only): 1. Through street: a. Park t~vo sides (1) R/W = 50 ;street width = 26' b. Park one side (1) R/W = 40'; street width = 20' 2. Newly-platted dead-end street less than or equal to 300 feet in length: a. Park 2 sides (1) R/W = 40'; Street width = 26' (or 24') b. Park one side (1) R/W = 35'; Street width = 20' (or 18') *3 Newly-platted dead-end street more Than 300 feet in length: a. Park 1 side (1) R/W = 40'; Street width = 28' b. No parking (1) R/W = 35'; Street width = 20' 4. Minimum sidewalk width = 5 feet. 5. Curb return radius = 30 feet..• A. In Comprehensive Plan Single Dwelling zones R7, R10, R20, RF: 1. Through street width: a. Park two sides (1) R/W = 40'; street width = 26' b. Park one side (1) R/W = 35'; street width = 20' 2. Newly-platted dead-end street less than or equal to 300 feet in length: c. Park 2 sides (1) R/W = 40'; Street width = 26' (or 24') b. Park one side (1) R/W = 35'; Street width = 20' (or 18') *3. Newly-platted dead-end street more than 300 feet in length: d. Park 1 side (1) R1W = 40'; Street width = 28' b. No parking (1) R/W = 35'; Street width = 20' 4. Sidewalk widths: a. In combination with curb 5 feet b. Separated from curb 4 feet 5. Curb return radius = 30 feet. * Unless queueing street approved by Chief of Bureau of Fire. C. TURNAROUND DIAMETER R/W Dia. = 80 feet. Paved Dia. = 70 feet. ~ ' ~ ~ i5{{~3~~~~'W1~~ ~L _ ' .q -J. rS~~l>in"C5t N Ly f'k~~S7-~7 "E~9a.. ~6 ' ;(~iO~17~Y 1 iLr~ti1~" o®o 0 0 0 0 aIE 12~ 3IE 31 20' ROADWAY 1 LANE 0 o ® o 0 0 ~e a~E 13~ i 3_~So~~ 9ke ~~j-a - R/W WIDTH CUT SLOPE FILL l SLOPE 3' PAVEMENT WIDTH 3' 2 1 - 6. 6 ~ ~ ~ C-r7o-wn ~ , SLOPE SLOPE 7/4'~---- i• I 1/4'~- Construct curbs as specified by City Engineer. MINIMUM PAVEMENT THICKNESS: 1 1/2" Asphalt Concrete Class "C" on 7 1/2` Asphalt Concrete Class "B" on 6" (1 1/2"-O) Crushed Rock Base (or 1"-O) (NOT TO SCALE) MINIMUM STREET AND RIGHT OF WAY WIDTH Pavement CONFIGURATION Width R/W Width Crown 2 Travel Lanes & 2 Parking Lanes 32' S0' 6" 2 Travel Lanes & 1 Parking Lane 28' 40' S" 2 Travel Lanes & No Parking 20' 35' 4" NOTES 1. Sidewalks, if required, shall be at least 5' wide, & shall be located no less than 6" from right of way line. 2_ Planting strips, if desired, shall be at least 4'-6" wide, measured from face of curb. 3. Any variation from this standard must be approved by the City Engineer. CITY OF PORTLAND, OREGON TITLE OF STANDARD PLAN STANDARD PLAN NO. LOCAL TRAFFIC STREET (NOT FOR USE IN ZONES R5, R7, R10, R20, ~ RF) ^ _ ~ ~ O APPROVE / - 110 NEV i5T 0115 oATE BY 3 1 CITY ENGINEER DATE CU7 SLOPE 2 R/W WIDTH 1~- FILL SLOPE - ' 2 3' PAVEMENT WIDTH 4.5' 4'z i ~ i L~ Crown SLOPE 1• 1• SLOPE 1/4'~- i/4"~- Construct curbs as specified by City Engineer. (NOT TO SCALE) MINIMUM PAVEMENT THICKNESS: 1 1/2" Asphalt Concrete Class "C" on 1 1/2" Asphalt Concrete Class "8" on 6" (1 1/2'-O) Crushed Rock Base (or 1"-0) TYPE OF PARKING R/W PAVEMENT MINIMUM MINIMUM CROWN STREET (i or 2 sides) wIOTH HIOTH COMB. S/W SEP'D. S/w THROUGH 2 401 26 5 42 5 THROUGH 1 35 3 20 5 4 z 4 Cl CUL-DE-SAC 2 40 264 5 42 5 300'. _ CUL-DE-SAC 1 35 205 5 q2 q </a 300' NOTE: For cul-de-sac streets longer than 300 ft. use LOCAL TRAFFIC STREET standards, per STD_ PLAN N0. 3-150, unless QUEUING STREET standard is approved by the Fire Marshall. i. In R5, 50' required. 4. Optional 24' (cul-de-sac compromise) 2. In R5, 5' required. 5. Optional 16' (cul-de-sac compromise) 3. In R5, 40' required NOTE: Use 30' curb return radius at intersections of SB' ar 20' queuing streets. CITY OF PORTLAND, OREGON TITLE OF STANDARD PLAN STANDARD PLAN N0. LOCAL GIUEUING STREET (FOR USE IN ZONES R5, R7, R10, R20 S RF) APPRO~/~ ~ N° ISIO~ ~ ~ s. 3 -15 0 A