Federico Puscar, MASc, P.Eng., PTOE

This paper demonstrates the diagnosis of bicycle safety issues and evaluation of proposed improvements at a major intersection in Vancouver, British Columbia using automated traffic conflict analysis. Traditional road safety analysis has often been conducted using historical collision records. However, limitations associated with collision data have motivated the development of complementary proactive techniques for road safety analysis. Recently, there has been significant interest in using… Show more

This paper demonstrates the diagnosis of bicycle safety issues and evaluation of proposed improvements at a major intersection in Vancouver, British Columbia using automated traffic conflict analysis. Traditional road safety analysis has often been conducted using historical collision records. However, limitations associated with collision data have motivated the development of complementary proactive techniques for road safety analysis. Recently, there has been significant interest in using traffic conflicts to analyze safety which has been strengthened by the availability of automated traffic conflict analysis tools. Automated computer vision techniques are used to extract and analyze traffic conflicts from video data. Traffic conflict indicators, such as time to collision and post-encroachment time, are used to identify safety issues based on the frequency and severity of conflicts. Spatial and temporal non-conforming behavior patterns are also analyzed. The intersection safety diagnosis reveals that the main sources of bicycle and motor vehicle conflicts are associated with failure to yield at bicycle crossings of on- and off-ramps, and vehicle red-light and stop-bar violations. A new intersection design is evaluated for its expected ability to address the identified safety issues. Show less

Active road users such as cyclists are usually subject to an elevated risk of collision. Therefore, there is a need for efficient techniques for evaluating the safety of active road users. Recently, there has been significant interest in using traffic conflicts to analyze safety which has been strengthened by the availability of automated traffic conflict analysis tools. This thesis demonstrates two applications of automated road safety analysis techniques using traffic conflicts.

The… Show more

Active road users such as cyclists are usually subject to an elevated risk of collision. Therefore, there is a need for efficient techniques for evaluating the safety of active road users. Recently, there has been significant interest in using traffic conflicts to analyze safety which has been strengthened by the availability of automated traffic conflict analysis tools. This thesis demonstrates two applications of automated road safety analysis techniques using traffic conflicts.

The first application is a safety diagnosis of a major intersection in Vancouver, British Columbia, with bicycle and pedestrian safety issues. The diagnosis revealed that the Burrard Bridge’s access and exit ramps are the main sources of conflicts at the intersection and their design encouraged many non-conforming behavior patterns. It can be expected that removing both ramps will address a significant amount of safety problems.

The second application covers a detailed analysis of cyclist yielding behavior at the same intersection. Cyclist yielding behavior is evaluated by analyzing vehicle and bicycle yielding rates in two bicycle crossings with different rules of priority. Compliance with traffic regulations is also studied by looking at how intersections actually operate in contrast to the formal traffic rules. Results showed that bicycle yielding rates can change significantly depending on the crossing’s configuration and legal right-of-way. Low bicycle yielding rates in combination with consistent but relatively low vehicle yielding rates can present a safety problem: understanding cyclist yielding behavior can enable engineers to design and build safer intersections which are consistent with road users’ expectations and to develop more realistic models of traffic behavior, safety, and operations. Show less

An assessment of road safety of the geometric design plans of the construction project of the National Route No. 4, section Chilamate-Vuelta Kooper is performed. The report is a response to the request submitted by the Technical Audit Department ( In Spanish, UAT) from Transportation Research Program (In Spanish, PITRA) by memorandum LM-UAT-02-2013.

The project is located between the cantons of Sarapiquí of Heredia and San Carlos of Alajuela, between the towns of Bajos de Chilamate and… Show more

An assessment of road safety of the geometric design plans of the construction project of the National Route No. 4, section Chilamate-Vuelta Kooper is performed. The report is a response to the request submitted by the Technical Audit Department ( In Spanish, UAT) from Transportation Research Program (In Spanish, PITRA) by memorandum LM-UAT-02-2013.

The project is located between the cantons of Sarapiquí of Heredia and San Carlos of Alajuela, between the towns of Bajos de Chilamate and Vuelta Kooper respectively. The road environment is predominantly rural, with large areas used for agricultural crops.

The geometric design showed good consistency with respect to the driver's expectation; only one section had a deficient local consistency.

The verification of compliance with the regulations geometric design is considered acceptable. The main failure is associated with the visibility distance available and the required, as several sections were determined with limitations in this parameter that could adversely affect the security level of the project.

The main recommendations are as follows: studies of pedestrian and cyclists mobility, to determine the feasibility of incorporating additional facilities. Review the locations of areas of permitted overtaking and road signs at points where sight distance is below the road's standard. Should be considered that the horizontal alignment of the project is predominantly flat with some undulations and slopes, it is possible that the operating speed is relatively high. Show less