Cycling at Intersections: A Multi-Objective Assessment for Traffic, Emissions and Safety

Abstract

This paper evaluated in an integrated manner the traffic performance, pollutant emissions and road conflicts between bicycles and motor vehicles at a signalized intersection. Two alternative scenarios were examined: (1) bicycles increment and motor vehicles replacement within the cycle-fixed traffic signal; (2) replacing the existing traffic control by a conventional two-lane roundabout and evaluating the impacts of bicycles increment. For each scenario, bicycle demand was varied from 9 to 270 bicycles per hour (bph). Traffic flow and vehicle dynamic data were collected from a three-leg signalized intersection in Aveiro (Portugal). The microscopic traffic model (VISSIM) paired with an emission (Vehicle Specific Power – VSP) methodology and safety (Surrogate Safety Assessment Methodology – SSAM) model were used to assess intersection-specific operations. The fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was used to find the optimal bicycle demands. The results showed that two-lane roundabout outperformed the existing traffic control, namely in highest bicycle demand scenario (number of stops and travel time reduced in 78 and 14%, respectively; CO2, NOx, and HC decreased 9, 7, and 12%, respectively). It was also found that the number of conflicts was significantly reduced (–49%) with this latter layout even in maximum bicycle demand scenario (270 bph). However, roundabout layout lead to more severe conflicts and potential crashes. The analysis showed that bicycle demands of 75, 95 and 110 bph delivered good environmental and safety outcomes for the intersection.

Alternatives to Improve Operational Traffic in Roundabouts Using Microsimulation

“…For future research, it is recommended to include a multi-objective analysis that allows evaluating the studied alternatives considering in an integrated way, traffic, polluting emissions, and road conflicts between walkers, bicycles, and motorized vehicles in this type of intersection [38].…”

Solving the multi‐objective bike routing problem by meta‐heuristic algorithms

“…Genetic algorithms have been used by Arunadevi et al (2007), who implemented a parallel genetic algorithm (PGA) using High-performance Cluster (HPC) and by Kang and Fricker (2018), who created a practical procedure to compute the cost function of each edge in a network for cyclists, incorporating distance and perceived risk. Bahmankhah et al (2019) implemented the NSGA-II to solve a threecriteria problem for short distance trips, while Nunes et al (2020b) proposed a genetic approach to solve the bi-criteria bike routing problem. Other meta-heuristics were implemented in routing context by Osaba et al (2018) to balance the trade-off between the length of the route and its safety level, and by Chang et al (2005) to find a set of nondominated paths in a dynamic network.…”

“…For this reason, few approaches employ this method to perform the search for feasible paths. For example, Bahmankhah et al (2019) employed the NSGA-II to find new numerical solutions for the considered cost functions, however, the feasible paths were proposed, based on the authors' simulation study. Li et al (2013) proposed operators for the NSGA-II algorithm in the context of MSP problem, however, the generation of the first population, as well as some other operators, have inefficiencies that are not suitable for real-time tools.…”

Analysis of the Influence of Sport Cyclists on Narrow Two-Lane Rural Roads Using Instrumented Bicycles and Microsimulation

“…There are many studies that have applied this methodology to the rural environment, with many different aims. However, there are few that use traffic microsimulation including motorized vehicles and cyclists, and all of them were developed in an urban context [22][23][24]. As a far as the authors are aware, microsimulation has not been used to evaluate the impact of interurban cycling.…”