Street Quality Research Articles

Design for movement: linking non-work travel and activity level to local urban design dimensions

With the arising sustainability issues related to both the natural and built environments along with health issues as a result of reduced activity, active modes of travel such as walking and bicycling are being investigated to increase their use to combat such issues in Australian cities. This study through an advanced behavioural modelling approach on four typical suburbs of metropolitan Adelaide, Australia confirms that urban design generally have a modest but sometimes statistically significant effect on modal choices. Well-connected streets, and close proximity to jobs and key functions were shown to induce non-motorised travel. Other exogenous environmental factors such as population density, street quality, and the level of public transport had little influences. From a urban design and planning policy perspective, this suggests that greater daily activity and consequent health and environmental benefits might accrue from designing human-scale, walkable communities that appeal to the preference of different social groups vs investment in master-planned communities in the hope of swaying travel behaviour. That is, pedestrian-friendly places suited to the taste preferences of socio-demographic groups might induce more physical activity over the long run through the process of residential self-selection than overt efforts to create fully planned, attractive and quality landscapes all over suburbia.

Development of Speed-Related Ride Quality Thresholds Using International Roughness Index

The International Roughness Index (IRI) has been used as a road roughness index on highways for nearly two decades. Research shows that subjective ratings such as present serviceability rating or mean panel rating could be reasonably predicted from IRI. Acceptable IRI values for highways have been developed and published by FHWA. Such IRI standards, however, are not applicable to local streets. Because vehicle speeds are lower on local streets, a comfortable ride can still be achieved at higher IRI values. There is a need to determine the acceptable IRI threshold values for local streets with various speed limits. Such IRI threshold values allow local pavement management officials to compare objectively the ride quality of streets with different speed limits. It was found that human ratings depend linearly on the logarithm of the rate of change of the vertical acceleration, namely, the jolt or jerk experienced by the raters. By analyzing the IRI records in the Long-Term Pavement Performance database and the corresponding calculated jolts, the authors found that jolt is linearly proportional to IRI at a given speed and approximately linearly proportional to the travel speed for a given IRI. By assuming further that the same jolt will lead to the same ride quality and that Interstate highways are operated at 120 km/h (75 mph), the authors use the jolt corresponding to the IRI thresholds set by FHWA for highways to develop speed-related ride quality thresholds at different travel speeds. The variation of jolt for roads with the same IRI value is also discussed.

Development of Speed-Related Ride Quality Thresholds Using International Roughness Index

The International Roughness Index (IRI) has been used as a road roughness index on highways for nearly two decades. Research shows that subjective ratings such as present serviceability rating or mean panel rating could be reasonably predicted from IRI. Acceptable IRI values for highways have been developed and published by FHWA. Such IRI standards, however, are not applicable to local streets. Because vehicle speeds are lower on local streets, a comfortable ride can still be achieved at higher IRI values. There is a need to determine the acceptable IRI threshold values for local streets with various speed limits. Such IRI threshold values allow local pavement management officials to compare objectively the ride quality of streets with different speed limits. It was found that human ratings depend linearly on the logarithm of the rate of change of the vertical acceleration, namely, the jolt or jerk experienced by the raters. By analyzing the IRI records in the Long-Term Pavement Performance database and the corresponding calculated jolts, the authors found that jolt is linearly proportional to IRI at a given speed and approximately linearly proportional to the travel speed for a given IRI. By assuming further that the same jolt will lead to the same ride quality and that Interstate highways are operated at 120 km/h (75 mph), the authors use the jolt corresponding to the IRI thresholds set by FHWA for highways to develop speed-related ride quality thresholds at different travel speeds. The variation of jolt for roads with the same IRI value is also discussed.

Automobile Drivers' Perceptions of Service Quality on Urban Streets

The Highway Capacity and Quality of Service Committee of TRB, which oversees the development of the Highway Capacity Manual, has formally recognized a need to improve the current level-of-service (LOS) methodologies. Among the concerns about the methodologies is the extent to which LOS estimates correspond to road users' perceptions. In recognition of these concerns, the objectives of this study were to ( a) develop and test a methodology to obtain drivers' opinions with regard to urban street quality of service (QOS), ( b) apply the methodology to identify the factors that affect drivers' perceptions of QOS on urban streets, and ( c) provide a qualitative foundation for the development of quantitative QOS tools that are based on the perceptions of drivers. This study used an in-vehicle field approach to determine the factors that affect automobile drivers' perceptions of service quality on urban streets. While driving on a preselected route, 22 participants in four cities were asked to speak aloud about their driving experience and the factors that influenced their perception of service quality. Afterward, drivers also completed a written questionnaire. The drivers expressed their opinions about a wide range of issues, including simple observations, more detailed evaluations, and broad concerns related to the roadway environment. From the drivers' comments, 40 factors were identified as relevant to their perception of service quality on urban streets. The authors believe that by identifying a wide range of factors that influence drivers' perceptions of service quality on urban streets, this study has increased the knowledge and understanding of the needs and values of automobile drivers on urban streets and has laid the groundwork for future studies aimed at developing quantitative QOS tools and models.

The role of design elements on the cost-effectiveness of streetscape improvement

This study discusses the effectiveness of contingent valuation methods in evaluating the visual quality of streets. Economic valuation methods provide effective design methods that balance cost-effectiveness with the quality of urban design. Research on conventional contingent valuation methods concentrates on estimating the total value of landscape resources such as forests, wetlands, and parks. In contrast, we assess street design plans from both economic and psychological points of view and analyze by factor analysis the relative importance of design elements such as vegetation, lighting columns, and pavements on the economic and perception-based values. We conducted experiments by using computer-simulated photomontage images as virtual alternatives for two street design projects in Saitama City. The elements considered various types of design with a varying cost of materials for street furniture. The respondents participating in this experiment were asked to evaluate the alternatives by a bidding game method, which is one of the elicitation methods used in contingent valuation. In the economic evaluation of alternatives, the availability of amenities and high design quality of a street are seen as benefits, and these can be compared with the material cost of an alternative. In this study, we use six indices for the economic evaluation of street design that include an acceptable cost derived from a contingent valuation method as well as composite indices related to the cost and benefits (cost ( C), amenity ( A), acceptable cost (AC), A/ C, AC/ C, A − C) and clarify their characteristics indicating cost-effectiveness. Acceptable cost had a strong correlation to the amenity score for each of the two street design projects. In addition, our analysis suggests that AC/ C is highly correlated to low cost plans and that A/ C is a moderate index balancing high amenity value and low cost. We also discuss how these six indices can help planners and designers in making decisions regarding the design strategy of a project. Our results should prove useful in actual street design where cost-effectiveness is an issue.

DB32 and the design of good urban streets

Good streets play a vital role in making cities work well: they provide networks for circulation, spaces for human interaction, conduits for services and (less tangibly) they define urban character. However, street design has become dominated by the requirements of the motor car and statutory services, enforced by legislation and standards. The other functions, equally important, have been pushed aside, leading to a decline in street quality and the urban environment. The problems caused by the unimaginative following of DB32 were addressed by the DETR in 1998 in its publication Places, Streets and Movement which showed how streets could be designed for the full range of functions, in particular promoting walking and cycling. This approach to street design reflects the Government's wider sustainability agenda, but it is often incompatible with the car-dominated standards of DB32. Most streets still give priority to the motor car, mainly because it is easier and safer, both for developers and local authorities, simply to follow the Standards than to take an imaginative approach to streets. DB32 needs to be revised to end the contradictions and to bring it into line with the more recent guidance, allowing local distinctiveness and good design, and recognising the full range of a street's functions.

DB32 and the design of good urban streets

Good streets play a vital role in making cities work well: they provide networks for circulation, spaces for human interaction, conduits for services and (less tangibly) they define urban character. However, street design has become dominated by the requirements of the motor car and statutory services, enforced by legislation and standards. The other functions, equally important, have been pushed aside, leading to a decline in street quality and the urban environment. The problems caused by the unimaginative following of DB32 were addressed by the DETR in 1998 in its publication Places, Streets and Movement which showed how streets could be designed for the full range of functions, in particular promoting walking and cycling. This approach to street design reflects the Government's wider sustainability agenda, but it is often incompatible with the car-dominated standards of DB32. Most streets still give priority to the motor car, mainly because it is easier and safer, both for developers and local authorities, simply to follow the Standards than to take an imaginative approach to streets. DB32 needs to be revised to end the contradictions and to bring it into line with the more recent guidance, allowing local distinctiveness and good design, and recognising the full range of a street's functions.

AN EXPERIMENT OF A TOWN CENTER TRAFFIC MANAGEMENT PACKAGE EMPLOYING TRAFFIC CAPACITY REDUCTION AND PUBLIC TRANSPORT PROMOTION-THE CASE STUDY OF TOYONAKA STATION DISTRICT

The objective of this paper is to present a review of the process and results of an experiment for traffic capacity reduction and street enhancement in a town center in Japan. Regeneration of town centers is one of the most important for keeping green mode transport patronage aiming at sustainable development. Most cities in Japan have old city centers and traffic management measures, such as the introduction of transit or pedestrian malls are necessary to revive these cities. Toyonaka station district in Osaka Prefecture is an old-fashioned style shopping area, consisting of narrow shopping streets linking to a railway station. Unfortunately, due to a large volume of motorized vehicles and, along with much on-street bicycle and loading vehicles parking, it has made the area undesirable for shoppers. A relief road is also congested by through traffic because it not wide enough. The Toyonaka municipal government and the Ministry of Construction has begun research into street quality improvement and carried out a traffic experiment for 4 days in April 2000.

Auto traffic noise, air traffic noise, and the environmental quality of city streets: Test of a model

In Jan. 1991 the Greater Cincinati Airport opened a new runway whose traffic flies directly over heavily populated residential areas which had little prior exposure to aircraft noise. Our evaluative study design replicated with modifications the classic and influential Appleyard and Lintell [(1969); Appleyard, LivableStreets (1981)] studies of the effects of auto traffic on residential life. As did Appleyard and Lintell, three streets were chosen called High, Medium, and Low, based on observed noise levels (and dBA measures of flights; many were found to be in the 90 to 100 dBA range), and conducted, using their questionnaire, 36 structured in-depth interviews with 12 randomly sampled households on each street, concerning five components of ‘‘perceived livability’’: traffic hazard; psychological stress, social interaction with neighbors; privacy and home territory; and environmental awareness. Residents gave numerical ratings of these components, as well as giving detailed verbal descriptions. Using ANOVAS and Tukey tests of the ratings, and structured analyses of the verbal descriptions, we found perceived livability was lowest on the High noise street and highest on the Low noise street, implying that the Appleyard and Lintell model for assessing residential livability effects of auto traffic noise is also useful for air traffic noise.

Visual Quality of Residential Streets: Both Street and Yard Trees Make a Difference

Past research has shown that street trees have a powerful impact on how people judge the esthetic quality of residential streets. In the study reported here, observers' ratings of the scenic quality of streets in photographs showed that trees on private property in front of homes also enhance the quality of the view down the street. Street trees contribute most to the visual quality of the street where there are few yard trees, and the least where there are many yard trees. This implies that arborists and urban foresters should give highest priority to planting street trees in neighborhoods where there are few yard trees.

Inequality, discrimination, and service delivery: A recapitulation for the public administrator

The equitable provision of urban public services has begun to receive increased attention from researchers, administrators, and the courts. Recent research has questioned the view that minority and low-income groups are systematically deprived in the distribution of public services, e.g. police and fire services, libraries, street quality and maintenance, and parks and recreational facilities. This paper reviews empirical studies in urban service distribution and judicial responses to municipal service claims. The research reveals that discimination in service delivery does exist. However, it is difficult to determine empirically in larger cities if a consistent pattern of discrimination exists and whether or not it bears a significant relationship to race or class. Discrimination and inequality on the basis of race has been subject to meticulous judicial prowess benefitting at one time or another the citizen and the municipality. The courts are requiring overwhelming statistical documentation to substant...