Effect of Lane Narrowing Implemented on an Urban Dual Carriageway on Speed Reduction and Acoustic Environment

The on-going growth in the use of motor vehicles leads to a number of traffic safety problems. Therefore, various traffic calming measures are applied to increase traffic safety in built-up areas. Lane narrowing is one of the techniques used to influence the perception of drivers and make them slow down. With this in mind, the authors conducted traffic volume and speed counts before and after installation of the lane narrowing treatment, covering 100 passing vehicles, at an intersection between an urban dual carriageway and an estate street where over a dozen fatal accidents occurred in the recent years. Traffic noise was also measured, both before and after lane narrowing. The traffic count data were analysed to show speed reduction by ca. 15 km/h, yet in all cases still above 50 km/h, which is the speed limit applicable to built-up areas in Poland. The analysis of the “before” and “after” noise maps showed only minor changes to the distribution of noise. The locations of these changes to the acoustic environment depended on the speed and volume of traffic and, much more importantly, on the topography of the surrounding area, the existing roadside layered landscape and the type of planted vegetation. The detailed analyses of the analysed parameters demonstrated that sustainable design of traffic calming measures on urban dual carriageways must consider not only the desired speed reduction but also the surrounding landscape and the local topography.

Synergy Effect of Factors Characterising Village Transition Zones on Speed Reduction

There are various traffic calming measures that can be installed in village transition zones. So far, focus was placed on diversified use of pavement markings, amounts of horizontal deflection, shape of the installed chicanes or central islands, presence of gateway, etc., and their location along the transition zone. However, the combined effect of the different transition zone factors on speed reductions has been rarely studied so far. Authors put forward a hypothesis of there being some determinants, which in combination influence speed reduction. To corroborate the hypothesis on the combined impact of the transition zone features on speed reduction in the village transition zones and to validate the established relationships the authors conducted verification study in transition zones containing chicanes or central islands. To verify this hypothesis the authors studied twenty transition zones and managed to confirm the hypothesis at 95% confidence level. The authors used previously adopted binary methods, verified the previously defined factors and added a few new determinants. The contribution of this study is a further investigation of the synergy effect of various relevant factors and the findings can assist in planning new transition zones or suggest additional measures to achieve the desired speed reduction in existing transition zones.

Evaluation of the Radar Speed Cameras and Panels Indicating the Vehicles’ Speed as Traffic Calming Measures (TCM) in Short Length Urban Areas Located along Rural Roads

Traffic calming measures (TCMs) are implemented in urban areas to reduce vehicles’ speed and, generally speaking, results are obtained. However, speed is still a problem in rural roads crossing small villages without a bypass and with short-length urban areas, since drivers do not normally reduce their speed for that short segment. Hence, various TCM can be installed. It is necessary to maintain a calm area in these short segments to improve road safety, especially for pedestrian aiming to cross the road, and to save combustible by avoiding a constant increase-decrease of speed. Four villages were selected to evaluate the efficiency of radar speed cameras and panels indicating vehicle’s speed. Results showed that the presence of radar speed cameras reduces the speed in the direction they can fine, but with a lower effect in the non-fining direction. Additionally, a positive effect was observed in the fining direction in other points, such as pedestrian crossings. Nevertheless, the effect does not last long and speed cameras may be considered as punctual measures. If the TCMs are placed far from the start of the village they are not respected. Hence, it is recommended to place them near the real start of the build-up area. Lastly, it was verified that longer urban areas make overall speed decrease. However, when drivers feel that they are arriving to the end of the urban area, due to the inexistence of buildings, they start speeding up.

THE EFFECT OF RESIDENTIAL LAYOUT DESIGN ON NEIGHBOURHOOD RECREATIONAL ACTIVITIES IN JOHOR BAHRU

In Malaysia, typically, the grid system of terrace houses layout has been dominated by landed housing in the property market for many years. The grid system of residential layout may offer more units to be built up by the developers. This situation may lead to fewer open spaces, playgrounds, and other recreational facilities in a strategic location within the neighbourhood schemes. Adopting some residential layout patterns may influence activities, frequency, interest, time, place, and route while doing their recreational activities. A study related to residential layout mainly focuses on building orientation, building design, privacy, safety, traffic calming, and social relation; however, a limited number of studies examine the effect of neighbourhood design on dwellers’ recreational activities routine and pattern. This paper aims to assess the relationship between residential layout design and its impact on dwellers’ recreational activities in well-planned landed neighbourhood schemes. Using observation, two (2) different residential layouts in Johor Bahru were selected as the study area, namely Taman Mutiara Rini (Presint Bakti), for the grid housing schemes and Taman Nong Chik Height for the innovative honeycomb layout. Descriptive analysis was used to analyse the data. Findings in this paper proposed recreational activities in the residential layout may be influenced by several design factors. The design of neighbourhood and outdoor open spaces, for example, played an essential role in residents’ evaluation of the various recreational activities. This study concludes that residential neighbourhoods design, including buildings and the neighbouring environment, significantly impacts people's ability to participate in neighbourhood recreational activities. Based on this research’s findings, residential layouts’ design in both study areas influenced local dwellers’ recreational activities types behaviour and preferred route through outdoor space arrangement.

Traffic calming in historic city centres - a case study

The aim of the paper is to compare the existing transport service solutions in the city centers of Bydgoszcz (Poland) and Hasselt (Belgium) that use the widely understood idea of calming the movement. The method of elaboration consisted of analyzes of the literature on the subject of the article, analyzes of available documents and local visits. The solution has been operating in Hasselt since September 2018, and in Bydgoszcz also since September, but 2019. Analyzed solutions in terms of traffic calming goals in these areas, implemented principles, methods used and traffic calming measures that are to lead to a consensus between traffic and the accessibility of the area and making centers living areas. The analyzes carried out confirm that the primary effect of leading to obtain areas centers as areas of “livable city" is to eliminate traffic not associated with a given area, the implementation of restrictions on the availability of cars while maintaining accessibility to public and residential buildings and creating preferences in terms of accessibility for pedestrians, bicycles and public transport. In both cities significant attention was paid to shaping public spaces for pedestrians and development of street fronts with facilities for attractive functions for center users and tourists. Analyzed examples of Bydgoszcz and Hasselt show that the implementation of a separated cycling infrastructure in the historic structure of centers is very difficult. For achievement of “livable city", special emphasis is placed on functional solutions and forms of pedestrian areas, taking into account the requirements of conservation protection, aesthetics and road safety.

Effect of Traffic Calming in a Downtown District of Szczecin, Poland

The increasing use of road vehicles has caused a number of transport and environmental issues throughout the world. To cope with them, traffic calming schemes are being increasingly implemented in built-up areas. An example of such schemes are Tempo-30 zones. The traffic calming measures applied as part of this scheme must be carefully planned in terms of location and design details in order to obtain the desired reduction in speed, traffic volume and exhaust emissions and, last but foremost, to increase the safety and facilitate the movement of vulnerable road users. The coexistence and combined effect of these measures and their design details must also be taken into account. The purpose of this study was to investigate whether the applied traffic calming measures had a considerable bearing on the reduction in speed to the desired level, as assumed in the traffic calming plan. Three street sections starting and ending with different intersection types were chosen to examine the synergy of the applied traffic calming measures. The numbers and speeds of vehicles were measured in three day-long continuous surveys. As it was expected, the amount of speed reduction depended on the hourly traffic volume on a one-way street and various other traffic engineering aspects. The obtained results may be used to modify the existing speed profile models and can guide traffic engineers in choosing the most effective traffic calming measures.

Evaluation of the Use of a Road Diet Design: An Urban Corridor Case Study in Washington, DC

A traditional road diet design converts a four-lane two-way road to a three-lane road consisting of two through lanes and a center two-way left turn lane. This paper introduces a new application of the road diet design in an urban corridor. Specifically, the new application converts a four-lane two-way road into a two-lane two-way road with full-time parking lanes in both directions. The paper analyzed the traffic impacts of the road diet application on the corridor of New Jersey Avenue, northwest, in the city of Washington, District of Columbia. The corridor included five signalized and one unsignalized intersections. Before-and-after analyses using Synchro 11 simulation and Site-Specific Empirical Bayes analysis were used to evaluate and compare existing and proposed scenarios. The proposed scenario provided various benefits including offering accessibility to the businesses in the area and acting as a traffic calming strategy. For signalized intersections, the overall performance remained the same for most intersections except for one intersection (on P Street), as it is significantly impacted by the road diet design due to the dramatic increase of traffic volumes in its minor streets as a result of diverting traffic volumes from the unsignalized intersection for left and through movements. Results showed that the use of a road diet design enhanced the unsignalized intersection performance due to the traffic volume divergence from its minor streets and enhanced the safety of the study area by decreasing the annual number of predicted crashes. To achieve better operational benefits and reflect traffic demands, the paper recommends to re-optimize signal timings when a road diet design is adopted.

Identification of the Determinants of the Effectiveness of On-Road Chicanes in the Village Transition Zones Subject to a 50 km/h Speed Limit

In recent years, in which a considerable increase in the road traffic volumes has been witnessed, traffic calming has become one the key issues in the area of road engineering. This concerns, in particular, trunk roads passing through small villages with a population of up to 500 and the road section length within the village limits of ca. 1400–1700 m. A successful traffic calming scheme must involve primarily effective reduction in inbound traffic speed. A review of the data from various countries revealed that chicanes installed in the transition zones may have a determining effect on the success of the traffic calming project. The effectiveness of such chicanes depends mainly on the type of chicane, its location on the carriageway, its shape and the size of the lateral deflection imposed by the chicane on the inbound lane. The purpose of this study was to identify the speed reduction determinants in traffic calming schemes in village transition zones, based on a central island horizontally deflecting one lane of a two-lane two-way road with 50 km/h speed restriction. As part of the study, vehicle speeds were measured just before and after the chicanes under analysis. Furthermore, the inbound lane traffic volumes were measured in field and a number of factors were identified, including the applied traffic management scheme, road parameters, view of the road ahead and of the village skyline, isolated buildings, road infrastructure and adjacent roadside developments. The obtained data were analysed with a method employing tautologies of the selected 32 factors affecting the drivers’ perception. A single aggregate parameter was proposed for assessing the coincidence of the influence of selected factors on speed reduction. The analysis of the existing schemes and the results of statistical analyses carried out in this study confirmed the authors’ hypothesis that the combined selected factors produce a desirable effect and that they should be additionally enhanced by the application of solar powered devices.