04-13-1994 Additions - Laserfiche WebLink

Home Browse Search

gh 0 6 00 a.- f. a.- n l- y ,s c e d c 2.03.05. Type of Curb. As may be expected. a wide divergence of opinion exists with respect to curb design. The advantages of vertical curb are: a. Pedestrians. street trees. utilities, and signs are best protected by the vertical curb. b. A positive limit of vehicle en- croachment an the border area is established. This minimizes parkway erosion and also reduces probability of vehicles sliding off the roadway under unfavorable pavement and weather conditions. c. Depression of curb is required at driveways. Such depression is de- sirable for clear identification of driveway, which minimizes block- age by curb packers. d. Excellent drainage control may be maintained by either variable height or standard height curb. e. Provides improved control of po- tential parked runaway vehicles. Advantages of the roll -type curb are: a. It is slightly less expensive than the vertical type. b. Some persons feel that the roll - type is the more aesthetically pleasing. c. Cheap driveway construction can be employed without curb depres- sion. This allows the subdivider and developer certain flexibilities in their constructions, in that driveway locations are not re- quired to be determined prior to curb installation. A discussion of curb types would not be complete without consideration of gutter design. Some municipalities use a separate vertical curb. Others employ a 12- to 18- inch -wide (30- to 46 -cm) gutter, poured integrally with the curb- ing. Still others employ large V -type gutter designs, or wide apron. high - slope gutters of 3 or 4 feet (1 to 1.2 m) in width. This variation in design policy is an important consideration in specify- ing street width. In Reference Number 2.03.04 (Table 1), the term "Pavement Width" is intended to be a practical driv- ing width available between faces of abutting curbs. In the case of the roll - type curb, in 12- to 18 -inch (30- to 46 -cm) gutter design. this distance is measured between points approxi- mately halfway up the roll curb. In the 2.00 DESIGN ELEMENTS FOR SCB01V9SION STREETS case of standard vertical curbs, with or without gutter widths of normal slope, the distance is measured face -to -Face of curb. In the case of large V- gutters or high -slope gutters. the width must be measured across only the pavement area within which the average driver oper- ates. The complete elimination of curbs poses a number of disadvantages as fol- lows: a. No protection is given to pedes- trians, street trees, and utilities. b. Border area erosion is prevalent. c. The roadway is poorly defined at night under rainy weather when asphalt surfacing is used. d. Positive control of drainage is to- tally lacking. Open ditch -type ad. jacent drainage facilities are cus- tomarily employed, which leaves the subdivision with a rural ap- pearance. e. Where asphalt surface is used, pavement edge raveling poses a maintenance problem. 2.03.06. Sidewalks and Bicycle Paths. In today's typical subdivision, sidewalks have the following function: a. Providing for maximum safety of children playing on their block. b. Protection of children walking to and from schools and neighbor- hood parks. c. Provision for adults to walk to and from neighborhood shopping and , transit stops (if any). Sidewalks should ordinarily be provided along streets used for pedes- trian access to schools, parks. shopping areas, and transit stops. Paved sidewalks should also be provided within pedes- trianways giving midblock access to these types of generators. Wider sidewalks may be considered next to higher density pedestrian generators, such as schools, transit stops, and churches. In the very low- density subdivisions, walking distance to regular elementary schools is often excessive. In com- munities where all such travel is by way of school buses. there will be less need for sidewalk construction as a standard policy. Page 9 The need for bicycle paths is a func- tion of subdivision density, area of the county. and proximity of bicycle - oriented generators such as educational institutions or parks. See source refer- ence No. 1 for design dimensions. There have been a number of initia- tives to provide accessibility for the handicapped through provisions such as sidewalk ramps. There is currently no consensus on when or where to include such provisions, or on the best design specifications. Until some consensus is reached, decisions on whether or not to include such provisions and the spe- cifics of design should consider local regulations and /or practice, and the number of persons benefited vs. those adversely affected (i.e.. wheelchairs vs. blind, handicapped vs. nonhandicapped. etc.) 2.03.07. Sidewalk Distance from Curb Face. (See Figure 2.) Many agencies specify a standard lo- cation for sidewalk 1 foot (0.3 m), from right -of -way line. This location has the following advantages where proper right -of -way width and attendant border area of 5 -foot (1.5 -m) minimum remain between the street edge of sidewalk and curb face: a. Children walking and playing side by side have increased safety from street traffic, b. Conflict between the pedestrians and garbage or trash cans awaiting pickup at the curb is eliminated by using the border area for such temporary storage. c. The warped area necessary for a proper driveway gradient is minimized by having a major por- tion of this gradient fall within the border area. d. Danger of collision by runoff-road vehicles is minimized by place- ment of the walk at maximum practical distance from the curb, and with further separation by tree plantings. e. Conflict with storage of snow plowed off the roadway is minimized. f. Pedestrians are less likely to be "splashed" by passing vehicles. When right -of -way restrictions result in a sidewalk next to the curb. an addi- tional width of 1 to 2 feet (0.3 to 0.6 m) is desirable.