Road transport harmful effects have to be more and more
integrated in urban planning. Therefore, urban planners may wonder what is the bad influence of their choices on road safety: what are the impacts of different
urban forms? Is it safer and to separate means of transport (i.e.: using pedestrian
and cycle paths) or to share the street?
Complete Streets
It’s not just about walking. Complete Streets work for everyone. We can restore an age-friendly network of smaller-scale streets as we reinvent suburbia and rebuild downtowns. Our youngest and oldest drivers then can safely move around the community instead of being forced onto those fast-moving five- and seven-lane roads. The same traffic-calming strategies that communities have applied to reduce speed and improve safety in existing neighborhoods can be used to design street networks that ‘get it right the first time.’ These new designs are called Complete Streets since they work for all users: walkers, bikers, drivers, and transit riders. With narrower lanes (to slow traffic speeds and reduce run-off), safer intersection designs (to reduce crashes and encourage crossing in the right place), curb extensions and median crosswalks (to shorten crossing distances and have a stopping place), bike lanes (to give bikes the same treatment as cars), wider sidewalks and street trees (to make walking a safe, pleasant option), and a host of other details, we can build Complete Street networks that make it easier for everyone to get around: driving, walking, wheeling, or taking transit. A well-planned system of clear, easy-to-read signage will also help us to get where we’re going, however we choose to travel. Growing Smarter,
Growing Smarter, Living Healthier: A Guide to Smart Growth and Active Aging, US EPA, 2009.56
Successful case of traffic planning in term of Design
A well-executed design process can build on early efforts in visioning, planning, and integration of transportation, land use, and housing, bringing them closer to implementation. Conceptual design is often where many of the most creative solutions are developed. Exploring alternative design concepts in the visioning process can help develop broad goals and objectives, while helping participants to understand the challenges and constraints of transportation facility design, engineering, and constructional. Many of the case studies faced significant challenges posed by existing conventional design guidance and regulations, requiring repeated efforts to get design exceptions.
Case Studies: Hillsborough Street Improvement Project
Introduction:
Hillsborough Street in Raleigh, NC, served a fundamentally urban, multimodal role in the community but had been assigned a role of moving high volumes of traffic. It is one of a limited number of east-west connections between Raleigh’s central business district and Durham and Chapel Hill, its partner cities in the region. This case study demonstrates that community objectives sometimes conflict with a roadway’s designation, but that appropriate design can help meet both community and transportation system goals.
The Hillsborough Street Partnership (HSP), a coalition of community members, businesses, civic organizations, and students. HSP began developing concepts for streetscape design and traffic calming along Hillsborough Street in 1999 and partnered with the City of Raleigh soon after.-led team identified principal concerns, including a high rate of pedestrian-vehicle accidents (four times the average for North Carolina State highways), lack of dedicated bicycle facilities and infrequent use of designated parallel bicycle routes, and problems with traffic flow when commuting and business traffic combined in peak travel hours. With city support, the team conducted a feasibility study to explore design options and test roadway performance using corridor simulations. The city’s involvement in a collaborative design process helped bridge the gap between the community-led effort and NCDOT, which retained control over the roadway.
The resulting two-lane road design used roundabouts to preserve traffic capacity, manage intersection congestion, and reduce delay while improving pedestrian crossing safety. At the time of design, Hillsborough Street carried 26,000 cars per day, with higher numbers forecast for the future. The reduction from four to two through lanes added on-street parking, bicycle lanes, and a landscaped median to restrict midblock left turns and provide pedestrian refuge in midblock crossings. Due to the high traffic volumes, roundabouts were used to improve traffic flow while maintaining turning movements. Since the inner travel lane on four-lane roads is frequently blocked due to left turns, the Hillsborough design limits direct left turn access into business driveways. Turning traffic passes its destination, uses a roundabout to make a U-turn, and makes a right turn at the destination.
Due to budget reasons, all the proposed roundabouts were not constructed. Several minor intersections use traffic signals, but the central raised median is replaced with left-turn lanes to preserve movement on the travel lane. At intersections without high levels of delay, modeling demonstrated that signalized intersections could handle traffic, saving funds to improve pedestrian crossings. The roundabouts critical to traffic operations at major intersections were constructed.
Case Study : Palm Canyon Drive
A primary commercial arterial in Cathedral City, CA, shows how integration of roadway and urban design can incorporate future land use plans and preserve future capacity. The project preserved a five-lane cross section as the principal roadway, while separating on-street parking and business access from through travel with a series of access lanes, using a modified form of the model of European and City Beautiful boulevards.
The original multiway boulevard design concept emphasized a flexible approach based on a range of adjacent development types. Design features such as sidewalks, on-street parking, and transit facility location were chosen based on the land uses desired for different parts of the corridor. Roadway construction included a landscaped center median, two travel lanes in each direction, and an additional landscaped median separating a new angled parking and transit lane from the through lanes. Implementation involved elimination of numerous angular driveways that had compromised traffic operations, and pedestrian-oriented intersection improvements to better connect the two sides of the street.
Source: Freedman Tung Sasaki.
Palm Canyon’s reconstruction was completed in 1998, and several of the accompanying downtown projects have also been completed. These include the new IMAX theatre, City Hall, and several mixed-use retail and housing projects. The multiway boulevard has shown notable safety improvements, both for motorists and pedestrians. The city’s traffic engineer noted after construction that the road, which averaged 3 pedestrian crashes per year in the mid-1990s, had not had any crashes reported.
Resources: ivability in Transportation Guidebook Planning Approaches that Promote Livability, USA
Complete Streets
It’s not just about walking. Complete Streets work for everyone. We can restore an age-friendly network of smaller-scale streets as we reinvent suburbia and rebuild downtowns. Our youngest and oldest drivers then can safely move around the community instead of being forced onto those fast-moving five- and seven-lane roads. The same traffic-calming strategies that communities have applied to reduce speed and improve safety in existing neighborhoods can be used to design street networks that ‘get it right the first time.’ These new designs are called Complete Streets since they work for all users: walkers, bikers, drivers, and transit riders. With narrower lanes (to slow traffic speeds and reduce run-off), safer intersection designs (to reduce crashes and encourage crossing in the right place), curb extensions and median crosswalks (to shorten crossing distances and have a stopping place), bike lanes (to give bikes the same treatment as cars), wider sidewalks and street trees (to make walking a safe, pleasant option), and a host of other details, we can build Complete Street networks that make it easier for everyone to get around: driving, walking, wheeling, or taking transit. A well-planned system of clear, easy-to-read signage will also help us to get where we’re going, however we choose to travel. Growing Smarter,
Growing Smarter, Living Healthier: A Guide to Smart Growth and Active Aging, US EPA, 2009.56
Successful case of traffic planning in term of Design
A well-executed design process can build on early efforts in visioning, planning, and integration of transportation, land use, and housing, bringing them closer to implementation. Conceptual design is often where many of the most creative solutions are developed. Exploring alternative design concepts in the visioning process can help develop broad goals and objectives, while helping participants to understand the challenges and constraints of transportation facility design, engineering, and constructional. Many of the case studies faced significant challenges posed by existing conventional design guidance and regulations, requiring repeated efforts to get design exceptions.
Case Studies: Hillsborough Street Improvement Project
Introduction:
Hillsborough Street in Raleigh, NC, served a fundamentally urban, multimodal role in the community but had been assigned a role of moving high volumes of traffic. It is one of a limited number of east-west connections between Raleigh’s central business district and Durham and Chapel Hill, its partner cities in the region. This case study demonstrates that community objectives sometimes conflict with a roadway’s designation, but that appropriate design can help meet both community and transportation system goals.
The Hillsborough Street Partnership (HSP), a coalition of community members, businesses, civic organizations, and students. HSP began developing concepts for streetscape design and traffic calming along Hillsborough Street in 1999 and partnered with the City of Raleigh soon after.-led team identified principal concerns, including a high rate of pedestrian-vehicle accidents (four times the average for North Carolina State highways), lack of dedicated bicycle facilities and infrequent use of designated parallel bicycle routes, and problems with traffic flow when commuting and business traffic combined in peak travel hours. With city support, the team conducted a feasibility study to explore design options and test roadway performance using corridor simulations. The city’s involvement in a collaborative design process helped bridge the gap between the community-led effort and NCDOT, which retained control over the roadway.
The resulting two-lane road design used roundabouts to preserve traffic capacity, manage intersection congestion, and reduce delay while improving pedestrian crossing safety. At the time of design, Hillsborough Street carried 26,000 cars per day, with higher numbers forecast for the future. The reduction from four to two through lanes added on-street parking, bicycle lanes, and a landscaped median to restrict midblock left turns and provide pedestrian refuge in midblock crossings. Due to the high traffic volumes, roundabouts were used to improve traffic flow while maintaining turning movements. Since the inner travel lane on four-lane roads is frequently blocked due to left turns, the Hillsborough design limits direct left turn access into business driveways. Turning traffic passes its destination, uses a roundabout to make a U-turn, and makes a right turn at the destination.
Due to budget reasons, all the proposed roundabouts were not constructed. Several minor intersections use traffic signals, but the central raised median is replaced with left-turn lanes to preserve movement on the travel lane. At intersections without high levels of delay, modeling demonstrated that signalized intersections could handle traffic, saving funds to improve pedestrian crossings. The roundabouts critical to traffic operations at major intersections were constructed.
 | ||
| Hillsborough Street—Hillsborough-Pullen and Oberlin-Pullen Roundabouts The roundabouts at the Hillsborough/Pullen (lower left) and Oberlin/Pullen (upper right) intersections reflect the variety of design options available in just this one type of intersection. Higher-volume, multi-lane roadways can still be accommodated with roundabouts through the use of two lanes in the circulating roadway.
Source: City of Raleigh, 2007.54
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| Hillsborough Street Intersection with Turn Lanes
In some cases on Hillsborough, property constraints and project cost led to the continued use of conventional signalized intersections. However, it is still possible to enhance these kinds of intersections to make them more livable: the use of curb extensions (on the upper-left corner of the intersection) and clearly marked crosswalks improve the pedestrian experience.
source: Source: City of Raleigh, 2007.55
The reduction of travel lanes restored space for on-street parking, bicycle lanes, and expanded sidewalks. The on-street parking allows for adjacent properties to maximize buildable area without needing to add on-site parking and circulation.
Lessons Learned
Local government involvement is essential to the success of community-led projects, especially when a State agency has jurisdiction over the project. North Carolina retains control over most roadways. Raleigh is North Carolina’s capital and second largest city, and NCSU is one of its premier educational institutions. Having a strong base of municipal and institutional support helped advance the project through design and construction.The project also demonstrates the effectiveness of roundabouts in reducing pedestrian-vehicle conflicts and untangling key operational complications of urban streets. Roundabouts allow free low-speed movement without stopping traffic like signalization, while separating pedestrians from the direct path of turning vehicles. Initial observations suggest that the roundabouts constructed from the original concept plan are meeting traffic flow objectives while greatly improving pedestrian conditions. The Pullen roundabout inside the NCSU campus has performed successfully and without accidents since its construction.
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Case Study : Palm Canyon Drive
A primary commercial arterial in Cathedral City, CA, shows how integration of roadway and urban design can incorporate future land use plans and preserve future capacity. The project preserved a five-lane cross section as the principal roadway, while separating on-street parking and business access from through travel with a series of access lanes, using a modified form of the model of European and City Beautiful boulevards.
The original multiway boulevard design concept emphasized a flexible approach based on a range of adjacent development types. Design features such as sidewalks, on-street parking, and transit facility location were chosen based on the land uses desired for different parts of the corridor. Roadway construction included a landscaped center median, two travel lanes in each direction, and an additional landscaped median separating a new angled parking and transit lane from the through lanes. Implementation involved elimination of numerous angular driveways that had compromised traffic operations, and pedestrian-oriented intersection improvements to better connect the two sides of the street.
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Cathedral City—Traffic Control Design ConceptPalm
Palm Canyon Drive’s design sought to balance vehicle mobility needs of a transportation agency with livability needs of the community. To achieve this balance, designers considered the supporting street network and access to it from Palm Canyon.
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Palm Canyon’s reconstruction was completed in 1998, and several of the accompanying downtown projects have also been completed. These include the new IMAX theatre, City Hall, and several mixed-use retail and housing projects. The multiway boulevard has shown notable safety improvements, both for motorists and pedestrians. The city’s traffic engineer noted after construction that the road, which averaged 3 pedestrian crashes per year in the mid-1990s, had not had any crashes reported.
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| Completed Palm Canyon Drive in the late 1990s. Source: Freedman Tung and Sasaki Urban Design, 2006.59 |
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