Speed and Lane Change Characteristics of Motorcycles at Priority Junction

Geometric and operational determinants of motor vehicle-bicycle overtaking on Brazilian urban roads.

OBJECTIVE Overtaking maneuvers between motor vehicles and bicycles (OVB) represent a critical hazard for cyclists due to required lateral clearances and vehicle speeds. This study aims to evaluate the OVB process in urban environments, focusing on the main geometric and operational attributes that influence cyclists' objective road safety indicators. METHODS A quasi-naturalistic observational study was conducted on urban roads in Fortaleza, Brazil, using an instrumented bicycle. Data on vehicle speed, lateral passing distance, lane configuration, vehicle type, and the presence of adjacent traffic were collected across 1,075 overtaking maneuvers. Statistical analyses were performed to assess the impact of these attributes on safety indicators. RESULTS Analysis revealed that 76% of observed passing maneuvers violated the Brazilian national recommendation of maintaining a minimum lateral distance of 1.50 m. The presence of cycling infrastructure and the absence of traffic in adjacent lanes were significantly associated with greater passing distances. Furthermore, a behavioral compensatory threshold was identified at a 0.85-meter lateral distance: drivers modulated speed as a risk-mitigation mechanism only during critical clearances, whereas no speed adjustments were observed at the 1.50-meter legal threshold. CONCLUSIONS A vast majority of drivers fail to comply with recommended passing distances, highlighting the need for targeted infrastructure and operational interventions. The existence of dedicated cycling facilities effectively improves lateral separation. Moreover, drivers adapt speed only under extreme proximity (under 0.85 m), demonstrating that legal limits alone do not induce safer driver behavior without structural or physical support.

Impact of vehicle type proportion and speed bump on traffic characteristics and emission

The installation of speed bumps on local roads in Indonesia is one solution to reduce vehicle speeds. Motorcycles and passenger car are the most common types of vehicles on local roads. The use of speed bumps can have environmental impacts due to traffic activity. The purpose of the research is to determine differences in the influence of the proportion of vehicle types on speed, fuel consumption, and emissions in conditions on and before speed bumps. Methodology of research is collecting traffic flow and speed census data by vehicle type for 6 days at the road segment point before the speed bump and on the speed bump location. The guidelines used in the research analysis are based on the Regulation of the Minister of Transportation of the Republic of Indonesia No. PM 14 of 2021 concerning Road User Devices and Safety, and the 2010 Environmental Guidelines, Indonesia. Principal results is when a vehicle travels over a speed bump, there is a significant change in speed, especially for motorcycles. Compared to motorcycles, the increased proportion of passenger car results in a more sensitive increase in fuel consumption and emissions. Contributions to the field is provide vehicle speed management especially on local road with many residential areas to improve air quality from the traffic perspective. Research limitation is limited to only two types of vehicles, namely motorcycles and passenger cars. Practical implication is can reduce climate damage caused by traffic activities, road user safety and social implication is improved safety and air quality and discipline in traffic. Vehicle speed restriction management on local roads with speed bumps to reduce emissions and fuel consumption usage is a maximum of 5.981 km/hour.

Analysis of Maneuver Time due to On-street Parking Near Signalized Intersections

The present study analyzes the variation in maneuver time of different vehicle types during on-street parking near signalized intersections with mixed traffic conditions. Traffic engineers frequently overlook this type of maneuver and their impact on a signalized intersection's performance while designing and assessing one. In this study, different type of vehicles, such as car, Two-Wheeler (TW), Autorickshaw (Auto), and Light Commercial Vehicles (LCV), are identified as parked vehicles near an intersection. Data on parking and maneuver time have been gathered from multiple Indian states. In this study, LCVs have the longest average maneuver time (MT) of 12.81 seconds (sec), followed by cars (10.25 sec), auto (7.58 sec), and TW (5.01 sec). According to these observations, maneuvering time (MT) for various types of vehicles operating in mixed traffic conditions vary considerably (5 to 13 sec). Further, the study analyzes vehicle MT among different vehicle classes and different intersections with parking maneuvers in the vicinity. The maneuver time (i.e., the time for which a parking vehicle blocks the traffic) observed in the present study is less than half of the benchmark values typically cited in capacity analysis guidelines. Notably, those conventional benchmarks are often applied uniformly, without differentiation across vehicle categories, approach volumes, or traffic composition. The outcomes of the current study will be useful for transportation planners to evaluate the performance of signalized intersections considering the effect of parking in the vicinity.

Effects of lane marking restrictions on driving safety of professional drivers at highway merging area in Hong Kong.

A merging area is one of the crash-prone locations in a highway network because of frequent lane changing, weaving, and merging behaviors. In Hong Kong, specific lane marking is implemented to guide traffic movements by keeping vehicles in designated lanes, reducing weaving, and channeling traffic. Therefore, conflicting traffic movements can be separated, and overall operational efficiency can be enhanced. However, the effects of traffic channelization through lane marking restrictions on the occurrence of traffic conflicts and associated risks to driving safety are less explored. In this study, the influence of lane marking restriction on traffic conflict risk involving merging traffic is investigated using vehicle trajectory data obtained from unmanned aerial vehicles. In particular, a two-dimensional modified time-to-collision-based indicator is applied to model traffic conflict risk involving lane-changing vehicles at a highway merging area. In addition to lane marking restriction, the influences of confounding factors including vehicle class, vehicle dimensions, and speed and acceleration profiles are also considered. A random parameters logit model with heterogeneity in means is then employed to account for the effects of unobserved heterogeneity. Results indicate that both-side restricted situation significantly reduces traffic conflict risk by limiting all lane-changing behaviors. Additionally, one-side restricted situation also exhibits favorable, even less remarkable, effect on traffic conflict risk. Furthermore, traffic conflict risk decreases for trucks because of the compensatory driving behavior of professional drivers, while the favorable effects of goods vehicles on traffic conflict risk are random. Nevertheless, the random effects of trucks can be moderated by lane change restrictions and lane changing behaviors. Findings should shed light on effective mitigation measures and traffic control strategies that reduce potential crash risk at the highway merging areas.

Analysis of the influence of traffic variables on lane change manoeuvres decision-making in real-world traffic scenarios.

This paper presents an analysis of lane changing manoeuvres under real traffic conditions, focusing on how drivers adapt their behaviour across different driving regimes. Using naturalistic driving data collected on a high-capacity road in Madrid (Spain), the research explores the role of traffic context in decision-making focusing on gap acceptance, vehicle dynamics, safety metrics and motivational factors. To analyse these dynamics, drivers were exposed to six controlled traffic configurations designed to reproduce representative real-world highway scenarios with different surrounding vehicle distributions, inter-vehicle distances, and relative speeds. Driver behaviour was analysed across three distinct manoeuvre phases, corresponding to car-following, anticipation, and lane change execution. The results show that traffic density and the surrounding environment significantly shape driver strategies. Higher traffic complexity leads to longer anticipation phases, greater dispersion in timing, and reduced safety margins. While Time-to-Collision (TTC) offers general insights into risk, gap-based metrics proved more stable and informative for predicting the actual execution of the manoeuvre. This study contributes to the understanding of context-dependent lane-change behaviour using controlled naturalistic driving scenarios. The findings support the development of predictive models and the design of advanced driver assistance systems (ADAS) and automated vehicles, enabling safer and more adaptive lane-change algorithms that better account for driver intent and traffic dynamics.

Analyzing continuous lane-changing behavior using freeway drone dataset