![[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Preamble Principal Authors James Daisa, PE Ove Arup & Partners, Ltd. San Francisco](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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Similaire à ITE RP Presentation (Part 3 Of 3)
Similaire à ITE RP Presentation (Part 3 Of 3) (20)
ITE RP Presentation (Part 3 Of 3)
- 1. Designing Walkable Urban Thoroughfares: A Context Sensitive Approach An ITE Recommended Practice Part 3 of 3
- 7. Streetside Zones Example Frontage Zone Throughway Zone Furnishing Zone Edge Zone
- 9. Example Streetside Design Parameters
- 10. Streetside Examples Context Sensitive Not Context Sensitive Photo: James M. Daisa, P.E., Arup Example: Retail Main Street
- 11. Streetside Examples Context Sensitive Not Context Sensitive Example: Urban Core Business District Photo: James M. Daisa, P.E., Arup
- 12. Streetside Examples Context Sensitive Not Context Sensitive Example: Urban Residential Photo: James M. Daisa, P.E., Arup
- 13. Streetside Examples Context Sensitive Not Context Sensitive Example: Historic District Photo: Kimley-Horn and Associates, Inc.
- 16. Furnishing Zone in Residential Context
- 17. Furnishing Zone in Commercial Context
- 20. Designing Walkable Urban Thoroughfares: A Context Sensitive Approach Photo: Dan Burden, Walklive.org Example: Use of fencing to buffer pedestrians from traffic
- 21. Curb Extensions Example: Mitigating narrow buffer between pedestrians and traffic Photo: James M. Daisa, P.E., Arup
- 23. TRAVELED WAY DESIGN Segment 6
- 31. Photo: Kimley-Horn and Associates, Inc. Example: Marked bike lane on a street in an General Urban context
- 34. Photo: James M. Daisa, P.E., Arup
- 37. Planning for Transit on Thoroughfares Type of Transit Local Bus Rapid Bus Bus Rapid Transit (BRT) Trolleys / Streetcar Light Rail Transit (LRT)
- 39. Considerations When Planning for Transit Thoroughfare Component Factors to be Considered Streetside Streetside width at stops or stations Space for passenger requirements such as shelters, seating, trees, lighting, etc. Accessibility requirements (lift pads) Traveled Way Available total right-of-way to accommodate running ways, stops and stations Lane width to accommodate transit vehicle in mixed flow lanes Type of running way and separation Median width to accommodate running ways and stations Pedestrian access to median stations Parking restrictions near stops and stations Bike/bus conflicts where buses stop in bike lane Additional width for transit facilities versus pedestrian crossing distance Horizontal and vertical clearances for transit Transit operations on one-way streets, location of stops, turns Overhead clearance for catenary power supply or trolley wires and space to mount poles
- 40. Photo: Texas Transportation Institute Example: Local bus route in a High Occupancy Vehicle (HOV) lane on an Urban Core avenue
- 41. Photo: James M. Daisa, P.E., Arup Example: Trolley in mixed flow lane with raised island stop
- 42. Photo: James M. Daisa, P.E., Arup Example: Shared bus and bike lane
- 43. Photo: James M. Daisa, PE, Arup Example: Light rail transit in separate right-of-way within an Urban Center boulevard
- 45. Example: Compact bus stop on Urban Center street with “lean bar” around street tree Photo: Kimley-Horn and Associates, Inc.
- 46. Photo: Dan Burden, Walklive.org Example: Bus stop Suburban boulevard
- 54. Median refuge island High visibility crosswalk markings Advanced warning signs Street and crosswalk illumination
- 57. Intersection Design Considerations Source: Community Design +Architecture and Urban Advantage Typical Auto-oriented Intersection Features
- 58. Intersection Design Considerations El Camino Real @ Los Robles – PROPOSED IMPROVEMENTS Source: City of Palo Alto CD+A, FPA, and Urban Advantage Source: Community Design +Architecture and Urban Advantage Features that Accommodate All Users
- 61. Curb Extensions
- 63. Photo: Dan Burden, Walklive.org Example: A low-speed channelized right turn lane with an uncontrolled crossing. Note the damaged mountable pavers likely caused by trucks.
- 64. Example: A conventional channelized right turn lane with an uncontrolled crossing. The at-grade channel through the refuge island conforms to ADA. Photo: Kimley-Horn and Associates, Inc.
- 66. Photo: James M. Daisa, P.E., Arup Example: Median refuge island with “Z” configuration on a General Urban boulevard A “Z” configuration directs pedestrians crossing the median to look toward oncoming traffic This tree must be pruned regularly to maintain proper sight distance and visibility between drivers and pedestrians
- 67. Photo: Kimley-Horn and Associates, Inc. Example: Multiway boulevard with refuge islands between the center thoroughfare and access lanes.
- 68. Modern Roundabouts Photo: Dan Burden, Walklive.org
- 69. Photo: Kimley-Horn and Associates, Inc.
- 70. Photo: Kimley-Horn and Associates, Inc. Photo: Kimley-Horn and Associates, Inc.
Notes de l'éditeur
- For the next few slides it is useful to think of the thoroughfare in terms of the three components shown in the diagram, the context, the streetside, and the traveled way. There is a 4th component not shown, that is intersections.
- When dealing with design issues for the roadside, the area between the face of curb and the property line, it is again useful to divide the area into zones, each which has its own function. The width of the roadside zones, and their function, vary by context and the activities generated by the adjacent land uses. That’s why one standard cross-section is usually inadequate to address the ever changing needs of urban roadsides. The RP contains detailed definitions of the functions of these zones.
- Roadside design is a lot more than simply determining how wide the sidewalk and the planting strip needs to be. In urban areas there are many functions expected of the roadside and its proper design needs careful thought. The roadside is the interface between the public and private properties and sometimes the line is blurred. Here is where the practitioner has the challenging task of integrating land use into thoroughfare design.
- The RP contains guidance on roadside design elements and dimensions under varying contexts. These, however, are only guidelines. The practitioner is encouraged to carefully consider the needed functions (which may be in the future) and allocate the appropriate width. This may require trade-offs with other thoroughfare design elements.
- This was designed for the current context, but also for some future context where there is more activity on the street. Each zone is adequately sized for its intended function.
- This is an example of a roadside design that has failed to meet the function of the roadside. Too much was put into a limited space, resulting in a design that is not sensitive to its context.
- The edge zone is essentially an operational clearance. Emphasize it does not represent a clear zone. Clear zones rarely can be achieved (and are not desirable) in urbanized areas. Use the RP considerations and guidelines to highlight a few issues related to design, but generally a minimum dimension is applied for this zone.
- Describe the definition of the furnishings zone and what it can be used for…point out the difference between its function in residential and commercial areas. Emphasize that the furnishing zone can be one of the most variable widths of the roadside. Use the RP considerations and guidelines to highlight a few issues related to design.
- This is an example of a furnishing zone in a residential context. Emphasize that in this context the zone is less modestly furnished, often simply a landscaped strip, and narrower. Both of these examples are located in Celebration Florida.
- The furnishing zone in commercial contexts ranges from simple zones to accommodate street furniture, utilities, and landscaping, to wide zones that accommodate transit stops and outdoor cafes. The example on the left is Santa Cruz California and the example on the right is Lake Oswego, Oregon.
- Describe the definition of the throughway zone and what its function, primarily for pedestrian passage and must meet ADA minimum requirements. Describe that the frontage zone can vary widely…at a minimum it should provide a shy distance from buildings and opening doors. It sometimes serves a similar purpose to the furnishings zone in that it can be used for street furniture, outdoor displays, and cafes. Use the RP considerations and guidelines to highlight a few issues related to design. The throughway example shown is from Culver City, California.
- One of the critical roles of the streetside is to buffer pedestrians from adjacent traffic. Studies show that the most important factor for this function is the distance between pedestrian and passing traffic. In urban areas distance is at a premium so more creative ways are used to provide an “effective buffer.” Ways include: On street parking Landscape strips with street trees Combinations of parking and landscaping In very narrow conditions, bollards may be used.
- In this example fencing is used to buffer pedestrians from traffic. It was also an opportunity to incorporate some aesthetic landscaping. This is also an example of a design, in this case a functional barrier, that requires regular maintenance. Flowers are high maintenance. In the CSS process, this type of feature is encouraged, as long as maintenance and landscaping stakeholders are included in the design process.
- Examples of curb extensions. Point out use of bollards to separate pedestrians from traffic. Some agencies frown upon the use of bollards as fixed objects.
- Clear zones are the outcome of the concept of the “forgiving highway,” providing space for errant drivers to recover before hitting something. This is a perfectly sound concept for high speed roads and highways., such as the condition shown in the top image. Some practitioners feel it is important to provide some level of clear zone on all types of thoroughfares, even in urban areas. In urban areas where the practitioner often has to scrounge for every inch of right of way to accommodate multiple demands for width, the fact is that clear zones are not practical or even necessary on lower-speed urban thoroughfares.
- For the next few slides it is useful to think of the thoroughfare in terms of the three components shown in the diagram, the context, the streetside, and the traveled way. There is a 4th component not shown, that is intersections.
- A schematic diagram of some of the components of an urban thoroughfare design. Point out a few of the components. Explain the complexity of integrating the components, particularly in constrained right of way.
- Similar to roadside design the design of the traveled way has a number of components and issues to address that go beyond just the capacity of the street. Again, often times there is not enough RW to design the ideal street so it is up to the designer and the stakeholders to evaluate the trade-offs and determine which elements have high priority.
- Emphasize that the recommended practice is consistent with AASHTO in urban areas with target speeds/design speeds of 35 mph or less: -The basic lane width for arterials is 11 feet -The basic lane width for collectors can go as low as 10 feet. Point out that the 12-foot lane width is used on streets with high volumes of transit vehicles and freight. (modern buses can be 10.5 feet in width, mirror to mirror). The determination of lane width goes beyond looking up a dimension in a table…the practitioner should consider the issues listed in the last bullet. Important not to combine minimum dimensions particularly when providing for bicyclists…do not want to squeeze bicyclists in a minimum width lane between minimal parking and travel lane widths.
- Describe the functions of a median: -Separation of opposing traffic movements -Width for turning lanes -A highly effective safety feature -Access management -Pedestrian refuge on long crossings (as long as appropriate width is provided) -Landscaping and utilities RP advocates raised curbed medians and does not necessarily support painted flush medians (e.g., continuous two-way turn lanes) in urban areas for pedestrian safety reasons. Highlight some of the dimensions.
- This may be one of the more controversial issues in the RP. There are many issues regarding the safety of trees in medians. At the same time, trees in medians are considered an important community asset and highly desirable in many places. Review the guidelines presented in the slide. Important to highlight the small caliper trees in medians on higher speed streets. This is a good slide to open a dialogue with the participants.
- Highlight issues with bike lanes adjacent to on-street parking: -door opening risks -minimal avoidance room Standard practice provides a combined 13-feet, but if RW is available increase the bike lane width. May want to describe other types of bike facilities not addressed in the RP: -Shared bike routes using “sharrows.” -Back in angled parking to address safety issues of angled parking on bike routes.
- Note that dimensions are consistent with AASHTO Green Book. Emphasize 8-foot wide parking lanes where high parking turnover is expected (commercial areas) Avoid widths below 7 feet. Point out that many drivers park up to 18-inches from curb. Preponderance of SUVs
- Discuss that mid-block crosswalks are typically not needed in highly urban areas with walkable block sizes and highly connected street networks. Consider midblock crosswalks to achieve good pedestrian spacing…BUT only where there is a strong and high pedestrian crossing demand. The criteria provided is from… Safety Effects of Marked vs. Unmarked Crosswalk at Uncontrolled Locations : Executive Summary and Recommended Guidelines , Federal Highway Administration, February 2002, Report No. FHWA RD-01-075.
- The RP contains a brief section on arterial speed management. This was based on research in best practices the authors conducted for the City of Pasadena to help them review new regulations for establishing speed limits in California. Most of the RP addresses design, but this section addresses retrofitting thoroughfares that have been inadvertently designed for high speeds, essentially arterial traffic calming. Hopefully, the CSS designer of urban thoroughfares won’t need to use the practices.
- Intersections are the most complex components of thoroughfare design and where most modal conflicts occur. Intersection design often requires balancing of design priorities to create safe and efficient facilities. This is a list of just some of the topics that need to be considered.
- Point out that intersection design in urban areas is a complex process that should be generally based on these principles.
- Emphasize that intersection design is the most complex aspect of thoroughfare design and is too broad of a subject to address in detail in the course. These are some of the more common design elements that typically need to be addressed.
- These are some of the features that improve the pedestrian environment at uncontrolled intersections.
- The next two slides show an example of some of the considerations in designing an urban intersection. Although it looks like a pretty typical suburban intersection, there are issues that would need to be considered in any redesign. These are highlighted.
- This is an example of an after condition with most of the issues addressed. Keep in mind that the CSS approach to thoroughfare design is an opportunity to enhance and improve upon the context, as well as address functional needs.
- Remind participants about design vehicle versus control vehicle. Discuss “effective width”…the actually turning radius of the vehicle within the r=travel lane as opposed to the exact radius of the curb.
- Emphasize the two primary functions of curb extensions: Improves visibility of both pedestrians and vehicles Shortens pedestrian crossing distance Describe that often used in conjunction with bus stops and increases area for transit users to wait and space for bus stop amenities. Remind users that can only be used on streets with on-street parking.
- Examples of curb extensions. In left example point out use of bollards to separate pedestrians from traffic. Some agencies frown upon the use of bollards as fixed objects. In right example, note that curb extensions are used as landscaping opportunities, but care should be taken as to not reduce the visibility advantage provided by the extensions.
- Discuss pros and cons of channelized right turns. In general, avoid their use in urban areas, but can be advantageous… -Where frequent large vehicles turn -At oblique angled intersections Regardless of use, should be designed to accommodate large vehicles and expedite right turns but at lower speeds.
- Example roundabout