Low-speed Roads Research Articles

Benefits of Short-Distance Walking and Fast-Route Scheduling in Public Vehicle Service

Public vehicle service (PVS), as a paradigm to manage and share large-capacity vehicles for public passenger delivery, is promising to improve the quality of urban transportation. In the PVS system, a command center receives requests sent by passengers, periodically assigns them to public vehicles and schedules vehicle routes to serve the requests. However, in the PVS system, the passengers’ waiting time is not well utilized. Moreover, it is observed that the driving distance on low-speed roads accounts for a rather high percentage. These two factors impact on system efficiency. In order to utilize the waiting time, we propose to let passengers walk a short distance instead of standing at their origins. At the same time, the driving distance on low-speed roads will be reduced. In this paper, the closest meeting point algorithm is proposed to address the challenge of determining the best pick-up and drop-off locations. The large-scale simulations show that the passenger walking and the proposed fast-route scheduling strategy can shorten the total vehicle travel distance by 34%.

Young Driver Crashes with Cyclists: Identifying Training Opportunities

To understand where driver training should focus to contribute to improving the safety of cyclists, this study compared bicycle-motor-vehicle (BMV) crashes involving novice drivers (under 25 years) with those involving experienced drivers in the Australian states of Victoria, Queensland, and South Australia. Novice drivers were involved in only a small proportion of BMV crashes and were not over-represented on a per-license basis. For both driver groups, most crashes happened on lower speed roads, at intersections, and during the day. In contrast to expectations, the distribution of types of BMV crashes differed little between experienced and novice drivers. The absence of major differences between experienced and novice drivers may result from learning opportunities being too infrequent in low-volume cycling countries, but this hypothesis needs further testing. A comparison between Queensland and Victoria showed three situations with a higher proportion of young driver crashes: in the evening in both states, Right through-opposing directions (Victoria only), and From footway-maneuvering (Queensland only). These patterns are likely to be indicative of young driver experiences. When their time on the road increases, so does their exposure to risk and to challenging driving conditions (e.g., driving in darkness). On the other hand, these patterns may also point to effects of legislation on young driver crashes, for instance cycling on the sidewalk in Queensland. The results suggest that training for novice drivers needs to supplement a wider strategy to improve cyclist safety (including infrastructure and traffic management improvements) and that training needs to be tailored to state-specific conditions.

The Influence of Pavement Degradation on Population Exposure to Road Traffic Noise

Road pavement develops distresses over time, which increase tyre/road noise. This work focuses on the impact of these distresses on environmental noise. To calculate the environmental noise, a method to transform Close ProXimity (CPX) measurement results into the required input for traffic noise models was defined and used. The tyre/road noise levels were determined by the CPX method for three types of pavement, with three types of distress, at three different speed levels. The study was carried out in the city center of Guimarães, a medium-sized Portuguese city. Using the NMPB model, 18 noise maps were produced for the passing of one single vehicle, taking into account two levels of distress (50% and 100%) for the pavement. The presence of distresses increased the noise, calculated at control points, by up to 7.1 dBA, and the percentage of the population exposed to levels over 45 dB was more than 11%. It was shown that pavement maintenance at early stages of distress development is, particularly for low-speed roads, very important to reduce environmental noise and population exposure. A comprehensive selection of the type of surface and speed control policies can mitigate the impact of a lack of maintenance.

Torque Analysis and Dynamic Performance Improvement of a PMSM for EVs by Skew Angle Optimization

In this paper, a permanent magnet synchronous machine (PMSM) for electric vehicles (EVs) is studied. Since EVs need to face some low speed road conditions, it is necessary to drive the machine to maintain a stable torque at low speed. The stator skew slot is often adopted to reduce torque ripple; however, it declines the output torque at same time. Besides, the difference between positive rotation performance and negative rotation performance, which caused by the skew slot are often ignored. Through the finite element analysis, the cogging torque and dynamic performance of the PMSM at different skew angle are studied. Moreover, the different influence of slot skew angle on positive and negative rotation performance is studied. Then, the optimum skew angle of the PMSM is studied through comprehensive consideration. Finally, the cogging torque of the prototype is verified to be less than 2N·m through the experiment.

Metropolis-Hasting based Expanded Path Size Logit model for cyclists’ route choice using GPS data

Abstract This study contributes to the field of cycling route choice by adopting the unprecedented combination of the Metropolis-Hastings (MH) path-sampling algorithm and the Expanded Path Size Logit (EPSL) model. The MH sampling approach is used to generate 15 alternative route choice sets for cyclists. The EPSL multivariate route choice framework is utilized to account for the correlation between sampled and non-sampled alternatives (joint MH-EPSL model). The data used in this paper is drawn from GPS data collected by the City of Toronto using a custom-built smartphone application in 2014–2015. The study focuses on non-work-related cycling trips (shopping, leisure, social and others) in downtown Toronto on weekdays. The estimated results indicate that the presence of bicycle lanes and road medians attractions and number of trees along the path have a positive impact on cyclist route choice. In general, cyclists prefer to take shorter routes on lower speed roads with less public transit stops especially during the evening rush hour, and less willing to take one-way streets, local roads, and steep road segments. These findings are useful to policy makers as well as transportation and urban designers when developing a cycling network aiming to attract more cyclists. Finally, our results indicate that the MH-EPSL model performance is an appropriate framework to study cyclists’ route choice decisions.

Characteristics of the close to home crash

Crashes are over-represented on roads close to home, but it is not clear why. We sought to address this gap by exploring the characteristics of close to home crashes. We used twelve months of crash data that included driver home address, and travel survey data captured over the same period to group crashes based on equivalent amounts of travel at different distances from home, controlling for exposure. We compared crashes on high-speed (rural) and low-speed (urban) roads; crashes caused by different types of error (lapse and violation); and crashes at major intersections (roundabouts and traffic signals), minor intersections (priority intersections and driveways), and midblocks; to find out which road type, error type, and locations were most common in crashes on roads close to home. Findings revealed that crashes over-represented close to home were on low-speed (urban) roads; were more likely to involve lapses of attention than violations; and that crashes related to lapses of attention on low-speed roads were more common at minor intersections and mid-blocks than at major intersections. Although drivers may be most likely to consider busy intersections risky and worthy of effortful focus, these results show that seemingly safe, slow streets and minor intersections account for a surprisingly high proportion of crashes overall, particularly on familiar urban roads close to home. The interplay of drivers’ attentional regulation with momentary driving demands, and risk is complex and worthy of continued investigation.

Skid Resistance of nano silica modified roller compacted rubbercrete for pavement applications: Experimental methods and response surface methodology

Roller compacted concrete (RCC) pavement usage is limited to low-speed roads due to its low skid resistance, caused by the smooth surface texture that makes it unsuitable for use in high-speed traf...

Comparison Different Black Spot Identification Methods

Abstract The identification of road sections characterized by high risk accidents is the first step for any successful road safety management process, considering the limited available resources. Although researchers started to study black spot decades ago, there are many un-clarified questions in this field. In the identification process of black spots three main methods can be used: screening methods, clustering methods and crash prediction methods. Many literatures and case studies were written describing each method pros or cons. These literatures concentrate mostly on one type of road each time, although road characteristics (i.e. speed, ADT) can highly affect the success and precision of the applied method. Therefore, the most important question to be answered is which method for which road?. This question can be answered by comparing different applied methods for different road types. However the comparison of different methods is still not adequately explored areas. This article aims to compare different methods used in identifying black spot; the sliding window and the spatial autocorrelation for two types of roads differ in their average speed, where speed is one of the important road characteristics which is still not adequately explored. The result shows a preference to use the sliding window for identifying black spot in high speed roads and the lack of preference to use it in low speed roads, and vice versa for spatial autocorrelation method, following accidents distribution pattern. And a result of a weakness in applying Empirical Bayesian in high speed road is also included.

Sleep-related vehicle crashes on low speed roads

BackgroundVery little is known about the characteristics of sleep related (SR) crashes occurring on low speed roads compared with current understanding of the role of sleep in crashes occurring on high speed roads e.g. motorways. To address this gap, analyses were undertaken to identify the differences and similarities between (1) SR crashes occurring on roads with low (≤60km/h) and high (≥100km/h) speed limits, and (2) SR crashes and not-SR crashes occurring on roads with low speed limits. MethodPolice reports of all crashes occurring on low and high speed roads over a ten year period between 2000 and 2009 were examined for Queensland, Australia. Attending police officers identified all crash attributes, including ‘fatigue/fell asleep’, which indicates that the police believe the crash to have a causal factor relating to falling asleep, sleepiness due to sleep loss, time of day, or fatigue. Driver or rider involvement in crashes was classified as SR or not-SR. All crash-associated variables were compared using Chi-square tests (Cramer’s V=effect size). A series of logistic regression was performed, with driver and crash characteristics as predictors of crash category. A conservative alpha level of 0.001 determined statistical significance. ResultsThere were 440,855 drivers or riders involved in a crash during this time; 6923 (1.6%) were attributed as SR. SR crashes on low speed roads have similar characteristics to those on high speed roads with young (16–24y) males consistently over represented. SR crashes on low speed roads are noticeably different to not-SR crashes in the same speed zone in that male and young novice drivers are over represented and outcomes are more severe. Of all the SR crashes identified, 41% occurred on low speed roads. ConclusionSR crashes are not confined to high speed roads. Low speed SR crashes warrant specific investigation because they occur in densely populated areas, exposing a greater number of people to risk and have more severe outcomes than not-SR crashes on the same low speed roads.

Investigating the effects of Rectangular Rapid Flash Beacons on pedestrian behavior and driver yielding on 25 mph streets: A quasi-experimental field study on a university campus

Rectangular Rapid-Flash Beacons (RRFBs) are safety measures that have become popular in recent years in the USA. Such equipment has demonstrated effectiveness in reducing vehicle speed and conflicts among road users, and increasing drivers’ yielding to pedestrians. However, RRFB effects on pedestrian behaviors are less well documented, and perhaps could produce contraindicated effects in crossing behavior. Specifically, RRFBs may give pedestrians a feeling of protection and induce them to more risk-taking when crossing the road. The current study was designed to investigate drivers and pedestrians’ reactions to a RRFB system installed at a university campus located in Virginia, USA. We deployed (a) field observation, using a multiple pretest/posttest non-equivalent control group quasi-experiment design and (b) interviews of students throughout the project’s multiple time periods. In total, 2454 pedestrians and 1312 drivers were observed and 265 students were interviewed. RRFB installations did not distinguish driver yielding likelihood between sites with or without RRFBs. However, driver yielding overall increased linearly over the five rounds of the study. Whether this was the result of the general presence of RRFBs on campus from the third round to the end of the fifth round is unknown. There is evidence from person interviews that students perceived increased safety for pedestrians over time. Being a RRFB chosen site or actual activation of the RRFBs did not have a significant relationship with pedestrian looking behavior either. The potential consequences of these results as well as the context of RRFB use on a university campus and generally low-speed roads are discussed.

Noisiness of the Surfaces on Low-Speed Roads

Traffic noise is a particular threat to the environment in the vicinity of roads. The level of the noise is influenced by traffic density and traffic composition, as well as vehicle speed and the type of surface. The article presents the results of studies on tire/road noise from passing vehicles at a speed of 40–80 kph, carried out by using the statistical pass-by method (SPB), on seven surfaces with different characteristics. It has been shown that increasing the speed from 40 kph to 50 kph contributes to the increase in the maximum A-weighted sound pressure level by about 3 dB, regardless of the type of surface. For larger differences in speed (30 kph–40 kph) increase in noise levels reaches values about 10 dB. In the case of higher speeds, this increase is slightly lower. In this article, special attention is paid to the noisiness from surfaces made of porous asphalt concrete (PAC), BBTM (thin asphalt layer), and stone mastic asphalt (SMA) with a maximum aggregate size of 8 mm and 5 mm. It has also been proved that surfaces of porous asphalt concrete, within two years after the commissioning, significantly contribute to a reduction of the maximum level of noise in the streets and roads with lower speed of passing cars. Reduction of the maximum A-weighted sound pressure level of a statistical car traveling at 60 kph reaches values of up to about 6 dB, as compared with the SMA11. Along with the exploitation of the road, air voids in the low-noise surface becomes clogged and acoustic properties of the road decrease to a level similar to standard asphalt.

Rollover Propensity of Heavy Vehicles at Roundabouts: Case Study on High- and Low-Speed Roads

In Indiana, roundabout construction recently commenced on high-speed roadways (i.e., with posted speed limits of 50 mph or higher), many carrying significant truck traffic. Studies show that heavy vehicle rollovers may be an issue at roundabouts. A case study compared the safety-related behavior of truck drivers at roundabouts on low- and high-speed roads. The rollover model is more suitable for truck trailers than previous models used for design considerations because it accounts for the complex paths and vehicle tilt of semitrailers and other heavy vehicles. The model was used to determine the difference between the critical rollover speed determined from the model and the observed vehicle speed. The proximity to rollover in the roundabout circulating lane was found to be different on low- and high-speed roads. However, this difference could not be explained by actual driver approach speeds. Drivers on the high-speed approach began decelerating earlier than those on the low-speed approach, and their deceleration rates were similar. In addition, vehicle speeds on the high-speed approach were only 1 mph faster than those on the low-speed approach close to the roundabout. The average minimum proximity to rollover on the circulatory roadway was about 3 mph slower on the low-speed, one-lane roundabout than on the high-speed, two-lane roundabout, and this difference might have been the main reason for higher risk of circulatory rollover in the one-lane roundabout.

Characterization of Half-Warm–Mix Asphalt with High Rates of Reclaimed Asphalt Pavement

Growing awareness about preservation of the environment has led asphalt technicians to assess and correct resulting impacts from the manufacture and application of bituminous mixtures. The concept of sustainability has come to the field of bituminous mixtures with two main components: reducing emissions and consumption of raw materials and preserving resources for the future. Conservation and rehabilitation activities of road pavements generate an increasing amount of waste from the milling of layers of damaged asphalt mixtures. This material, having great costs and exceptional properties, should be reused in manufacturing new mixtures of the same type and function. This paper presents efforts carried out to develop a technology allowing manufacturing and applying half-warm mix asphalt in surface layers of low-speed roads at low temperatures by using high percentages of reclaimed asphalt pavement. Continuously graded mixtures were manufactured at 100°C and compacted at 80°C with different percentages of RAP, from 50% to 100%. Results obtained from testing laboratory specimens indicated that their mechanical properties, cracking resistance and fatigue resistance, were close to those expected from regular hot-mix asphalt mixtures. Additionally, a field study was carried out in which this technology was put to use. First field cores were extracted and tested from old pavement and then the RAP coming from this pavement was employed to manufacture laboratory specimens with different gradations, RAPs, and emulsion contents. Results showed that use of this technology provided the new mixture with improved fracture properties and ductility with respect to the old pavement mixture.

Associations between the neighbourhood built environment and out of school physical activity and active travel: An examination from the Kids in the City study

This study's aim was to examine selected objectively-measured and child specific built environment attributes in relation to proportion of out-of-school time spent in moderate-to-vigorous physical activity (%MVPA) and active travel in a group of ethnically and socio-economically diverse children (n=236) living in Auckland, New Zealand. Street connectivity and distance to school were related to the proportion of trips made by active modes. Ratio of high speed to low speed roads and improved streetscape for active travel were related to %MVPA on weekdays only. Inconsistent results were found for destination accessibility. Local destinations (particularly schools) along a safe street network may be important for encouraging children's activity behaviours.

A35 The relationship between walking and cycling of youth and urban form: a Heckman selection model of active travel mode and

Abstract Background Active travel of children and adolescents is a major public health challenge, which when promoted, offers immediate health benefits and forms future sustainable travel habits. Studies show that urban form is essential for encouraging children to use non-motorized modes. Existing studies have five limitations. Firstly, they explored the relationship between urban form and the odds of active travel while neglecting the amount of active travel. Secondly, they focused on exclusively on walking. Thirdly, they were conducted in car-oriented countries. Fourthly, they did not base their analysis on detailed GIS databases. Last, they focused on 9-12 year-olds, which cannot be readily extended to older adolescents because of changes in parental attitudes. Methods We focus on the relationship between children’s mobility and measurable aspects of urban form and overcome the aforementioned limitations. We explore jointly the choice and the extent of active travel of youth while distinctly considering walking and cycling, controlling for urban form measures, and taking both a “street view” looking at the immediate home surroundings and a “bird’s eye view” looking at wider neighbourhoods. A Heckman selection model represents the distance covered while cycling (walking) given the mode choice being bicycle (walk) for a representative sample of 2,336 travel-activity diaries 10-15 year-old children from the Capital Region of Denmark extracted from the Danish national travel survey and combined with GIS sources and the Danish national transport model. Results Higher probability to cycle as active travel mode and longer cycling distances are related to older age of the youth and escorting by the parents, with the latter being the most dominant effect among the socioeconomic characteristics. Higher probability of cycling is positively related to: high density of low-speed roads within 1.5 km from the children’s house, not having a train station with 1 km from home, low intersection density, lower car and heavy vehicle traffic densities, lower crash densities, and low share of immigrants. Conclusions Policy implications are: i) the necessity of different urban environments for walking and cycling, as the former relates to “street view” urban form and the latter also to “bird’s eye view”; ii) the need for measures aiming at traffic reduction and speed calming, diminution of heavy vehicle movements, lessening of cyclist-motorist conflicts at intersections, and decrease of cycling crashes, ii) the need for campaigns addressing social norms in neighbourhoods located outside the city or with higher percentages of immigrants in order to motivate active travel of children.

Effects of Pavement Surface Conditions on Traffic Crash Severity

AbstractImproving road safety through proper pavement maintenance is one of the goals of pavement management. Many studies have found that pavement conditions significantly influence traffic safety. Although several studies have explored the relationship between pavement conditions and crash occurrence, the effect of poor pavement conditions on crash severity levels has not been investigated, especially by using a discrete model that can handle ordered data. This paper focuses on the development of the relationship between poor pavement conditions and crash severity levels using a series of Bayesian ordered logistic models for low/medium/high speed roads and single/multiple collision cases. The Bayesian ordered logistic regression models indicated that the poor pavement condition decreases the severity of single-vehicle collisions on low-speed roads whereas it increases their severity on high-speed roads. On the other hand, the poor pavement condition increases the severity of multiple-vehicle crashes on ...

Minor Road Traffic Delays at Priority Junctions on Low Speed Roads in Suburban Areas

Traffic delay is one of the important aspects considered in the assessment of the operational performance of intersections. In the analysis of priority or unsignalised junctions, delays to minor road vehicles are often estimated using the existing mathematical models. However, the applicability of such a model depends on the basis and the source of the data with which the model was calibrated. This study was carried out to evaluate traffic delays to minor road vehicles at priority junctions in suburban areas. The data were collected at two priority junctions using video recording technique. The results showed that the day time delays were longer than of those observed during the twilight time. In both situations, delay to minor road vehicles increases as the volume of major road traffic increases. However, the effect of conflicting volume on the delay to the minor road vehicles is not clear. The comparisons between observed delay and the values predicted using the HCM and Tanner’s models indicated that, in general, the observed delays are much lower than the values predicted by both models particularly during the day time. Such a finding suggests that both HCM and Tanner’s models are not directly applicable to the analysis of delays at priority junctions in Malaysia.

Musical hallucination following whiplash injury: case report and literature review

A musical hallucination is defined as a form of auditory hallucination characterised by the perception of music in the absence of external acoustic stimuli. It is infrequently cited in the literature, although population studies suggest a greater prevalence. The aetiology of this unusual disorder remains unclear. A 70-year-old man with acquired hearing loss suffered a whiplash injury in a low-speed road traffic accident, and subsequently presented with bilateral 'tinnitus.' On closer questioning, he described hearing orchestral music. There was no evidence of psychosis, delirium or intoxication, and the patient was managed expectantly. This patient represents the first published case of musical hallucination precipitated by whiplash injury. We explore the possible pathophysiological underpinnings of musical hallucination and highlight the need for a greater awareness of this disorder. A management strategy is suggested.

Relative Risks of Deer–Vehicle Collisions Along Road Types in Southeast Michigan

Deer–vehicle collisions (DVCs) are a substantial hazard throughout much of North America. Our objective was to determine relative risk for DVCs based on road characteristics and dominant land cover types, and to illustrate the use of relative risk assessment in wildlife management. Relative risk compares the probability of being in one event relative to the probability of being in another event. We determined relative risk of DVCs by comparing 1,350 DVC locations against 1,350 randomly selected non-DVC locations within three counties in southeast Michigan. Relative risk of a DVC was greater on rural roads compared to urban roads, roads with traffic volume >120 vehicles/h compared to roads with ≤120 vehicles/h, and high and medium speed roads compared to lower speed roads. Our findings provide guidance for identifying risks of DVCs related to road attributes, and prioritizing management strategies in an objective manner to mitigate risk from DVCs.

Stop versus yield on pedestrian-involved fatal crashes in the United States

In an effort to improve pedestrian safety, several states in the United States changed their pedestrian laws by changing the requirement that drivers yield to pedestrians in crosswalks to a requirement that drivers stop for pedestrians in crosswalks. This study examined whether this change had an effect on pedestrian safety in the United States, with its focus on low-speed roads. To examine the association between changes in pedestrian laws and changes in pedestrian-involved fatal crashes, three approaches were employed: before–after analysis, time-series analysis, and cross-sectional analysis. Pedestrian-involved fatal traffic crashes on low-speed roads were extracted from the U.S. national fatal crash database, the Fatality Analysis Reporting System (FARS), from 1980 through 2005. This study found no statistically significant reduction in pedestrian-involved fatal crashes attributable to changes in the laws, yet this finding is not definitive because of study limitations such as the omission of relevant exposure data.