Author: Sam Doecke Publisher: ISBN: 9781921645235 Category : Roads Languages : en Pages : 19
Book Description
This report describes the path of vehicles following a collision with another vehicle at a rural intersection. Detailed information from in-depth investigations of 70 intersection crashes was analysed. Rear end crashes at intersections were excluded as were collisions involving a motorcycle. Intersection geometry, speed zone, impact point and mass ratio influence the nature of the post impact trajectory of the vehicles involved. As the results show a high number of vehicles travel a large distance at a shallow angle following an intersection collision, extending crash barriers on the through road (the road with the right of way) right up to the intersection may have some benefit. Clear zones surrounding the intersection are also advisable and have an added benefit of increasing sight distance. Hazards can be assessed for removal or relocation by applying the results of this study. Keywords: Intersection, rural road, traffic accident.
Author: Sam Doecke Publisher: ISBN: 9781921645983 Category : Roads Languages : en Pages : 38
Book Description
This report describes the path of vehicles following a collision with another vehicle at a metropolitan intersection. The aim was to provide guidance to transport authorities on roadside design at intersections to protect vehicles from secondary impacts with roadside objects. Detailed information from in-depth investigations of 78 intersection crashes was analysed. Crashes at singalised and unsignalised intersections were analysed separately. Thirty two vehicles at signalised and unsignalised intersections (16 at each) were involved in a secondary collision. Nine of these collisions were more severe than the initial vehicle-to-vehicle collision, three at signalised intersections and six at unsignalised intersections. Following the vehicle-to-vehicle impact at both signalised and unsignalised intersections, more than half of the vehicles came to rest within 10 metres of the impact point. However, more than a quarter travelled 15 metres or further and around 10% travelled further than 27 metres. It was found that 40% of vehicles at signalised intersections crossed the designated pedestrian crossing areas following a collision between vehicles. It was also found that 14% of vehicles involved in crashes at signalised intersections departed the roadway. This poses a significant risk to pedestrians who are in the vicinity of junctions at the time of collisions. Graphical representations of the percentage of vehicles that travel through a given sector relative to the impact point following the metropolitan intersection crashes were developed. These can be used to determine the chance of a vehicle having a secondary collision with roadside objects.
Author: Yousteena Bocktor Publisher: ISBN: Category : Languages : en Pages :
Book Description
"Motor-vehicle turning maneuvers at intersections are often involved in crashes and serious injuries, in particular collisions involving vulnerable road users. In Canada alone, 30% of fatalities and 40% of serious injuries took place in intersections. Thus, to improve intersection safety, geometric design related treatments have been implemented and studied in past literature. These include curb radius reduction and curb extensions which aim to reduce turning speeds and crossing distances. The radius effects and treatments have been investigated for large intersections and road curves in rural areas using observed crash and point-speed measures, with limited studies examining small urban intersections. With the help of modern data collection techniques (video footage and GPS data), this study aims to fill the gaps presented in the literature on the investigation of the safety of curb radii and other geometric elements in local urban intersections using surrogate safety measures derived from vehicle trajectories and statistical regression models. More specifically, this research aims at: (1) develop a methodology to evaluate the impact of the curb radius on the speed of vehicle turning maneuvers in local intersections with small radius using Montreal video trajectory data and a cross-sectional approach. (2) To evaluate the safety effectiveness of curb radius reduction as a traffic calming treatment using a naïve before-after study and video data collected from two intersections in Toronto, Canada. In addition to speeds, post-encroachment time is used as a surrogate indicator, (3) To expand on the use of GPS smartphone data for establishing a methodology for evaluating the safety of turning movements to overcome the shortcomings of video cameras. For this purpose, GPS-based surrogate safety measures (85th percentile, median speeds, and deceleration) were extracted and modeled using mixed-effect regression models for a large data set from Quebec City.Among other results, a statistically positive and significant association between the radius and speed measures was observed for the video trajectory data. For instance, in the cross-sectional analysis, an increase of 1-meter in the curb radius results in an increase of 0.775 kph for the 85th speed and 1.208 kph for the median speed for all turns. For the before-after study, an average decrease was witnessed for all speed measurements for both intersections studied after the curb reduction treatment implementation. The countermeasure contributed to 1.6 kph and 0.783 kph decrease for 85th percentile and median speed, respectively, for both intersections when examined using the mixed-effects linear regression models. Lastly, using GPS smartphone data, the findings also support the relation between exhibited speeds and the measured corner curb radius. Using regression models of speeds, for every 1-meter increase in the measured curb radius, a statistically significant increase of 0.4 kph in both 85th percentile and median speeds was observed. Other intersections attributes, like the signalization, had an influence on the speed measures. As for the deceleration models, an increase of 1-meter in the radius resulted in a 0.01 m/s2 increase in the severity, thus, decreasing the safety of the intersection. Overall, the effectiveness of curb radius and reduction treatment was confirmed in the three different case studies. Despite the modest impacts in most of the cases, the importance of radius reductions is implied. Also, future work is required to address the limitations presented by the filtering techniques for the GPS data. Moreover, cross-calibration of the models can be used to evaluate the means of data collection by collecting GPS data for the video trajectory models and vise-versa"--
Author: American Association of State Highway and Transportation Officials. Task Force for Roadside Safety Publisher: ISBN: Category : Roads Languages : en Pages : 560
Author: ITE (Institute of Transportation Engineers) Publisher: John Wiley & Sons ISBN: 1118762304 Category : Technology & Engineering Languages : en Pages : 688
Book Description
Get a complete look into modern traffic engineering solutions Traffic Engineering Handbook, Seventh Edition is a newly revised text that builds upon the reputation as the go-to source of essential traffic engineering solutions that this book has maintained for the past 70 years. The updated content reflects changes in key industry standards, and shines a spotlight on the needs of all users, the design of context-sensitive roadways, and the development of more sustainable transportation solutions. Additionally, this resource features a new organizational structure that promotes a more functionally-driven, multimodal approach to planning, designing, and implementing transportation solutions. A branch of civil engineering, traffic engineering concerns the safe and efficient movement of people and goods along roadways. Traffic flow, road geometry, sidewalks, crosswalks, cycle facilities, shared lane markings, traffic signs, traffic lights, and more—all of these elements must be considered when designing public and private sector transportation solutions. Explore the fundamental concepts of traffic engineering as they relate to operation, design, and management Access updated content that reflects changes in key industry-leading resources, such as the Highway Capacity Manual (HCM), Manual on Uniform Traffic Control Devices (MUTCD), AASSHTO Policy on Geometric Design, Highway Safety Manual (HSM), and Americans with Disabilities Act Understand the current state of the traffic engineering field Leverage revised information that homes in on the key topics most relevant to traffic engineering in today's world, such as context-sensitive roadways and sustainable transportation solutions Traffic Engineering Handbook, Seventh Edition is an essential text for public and private sector transportation practitioners, transportation decision makers, public officials, and even upper-level undergraduate and graduate students who are studying transportation engineering.
Author: Sam Doecke
Author: Sam Doecke
Author: Yousteena Bocktor
Author: Richard I. Emori
Author: 
Author: 
Author: American Association of State Highway and Transportation Officials. Task Force for Roadside Safety
Author: Andrew Vogt
Author: Cara Lynn Kienert
Author: ITE (Institute of Transportation Engineers)