In the road design process, speed variation along the road segment is an important issue to consider in adapting road geometry to drivers' expectations. To achieve this objective, speed criteria are used to evaluate road consistency. Being able to estimate the operating speed in the design phase can lead to safer road alignment. With this objective, several researchers have developed operating speed models. Most of these models are based on collected spot speed data. They assume constant speed on curves and, therefore, deceleration that occurs entirely on the approach tangent. According to these assumptions, spot speed data are collected at the center of the horizontal curve and at the midpoint of the preceding tangent to obtain operating speed models. This paper presents a new methodology based on the use of Global Positioning System devices that allow continuous collecting and processing of speed data. With this new methodology, not only can new and more accurate operating speed models be developed, but cited hypotheses can also be checked. Observed speed continuous profiles allow studies that previously could not be done, especially as related to deceleration and speed variations. This study calibrated new speed models, including three for horizontal curves with a radius curve and the curvature change rate of a single curve as explanatory variables, and one for tangents that incorporates the curve speed model. Tangent-curve speed variations are evaluated, with comparison of Δ₈₅V and ΔV₈₅, analysis of the deceleration length occurring on a curve, and development of two deceleration models.

In the road geometric design process, speed variation along the road segment is one of the most popular criteria to evaluate road consistency, hence the importance of estimating operating speed and its variations. Most of the estimation models are based on speed spot data collection, usually assuming some hypotheses like operating speed remains constant at curves and speed variations take place entirely at preceding tangent. This paper presents the results of the study of the deceleration phenomenon using a new methodology based on data collection by global positioning system devices. By means of this new methodology, not only new and more accurate models can be developed, but also the previous hypotheses can be checked and new studies can be carried out. Tangent-to-curve speed variations have been evaluated, comparing the 85th percentile speed differential (Δ85V) and the differential of the 85th percentile operating speed (ΔV85), analyzing the percentage of deceleration length that takes place at...

Overtaking is one of the most dangerous manoeuvres on two‐lane rural highways. The most influential factors are related to drivers, so ITS and assistance systems are not yet common. This research is based on experimental data of overtaking manoeuvres collected using an instrumented passenger car, equipped with four cameras, laser rangefinders and a global positioning service (GPS) tracker. This vehicle was driven along four different road segments in the surroundings of Valencia (Spain) at a speed slightly slower than the operating speed of each segment. Overtaking time and speeds were measured. Unlike previous work, the influence of human factor was also considered. Age and gender of overtaking driver, as well as time spent following were used to characterise this influence. More than 200 manoeuvres were recorded and the influence of driver characteristics and delay on gap acceptance, manoeuvre duration and speed differences have been analysed. Results show differences in behaviour between age and gender groups, since young male overtaking drivers have shown a more aggressive behaviour. Overtaking times were around 1 s lower than other drivers, whereas average speed difference was 4 km/h higher. Collected data and their analysis have provided a basis to review design criteria and to develop future assistance systems.

Mobility patterns and lifestyles have changed in recent years in cities worldwide, thanks to the strong rise in modes of travel commonly referred to as micromobility. In this context, e-scooters have experienced a great rise globally which has led to an increase of crashes involving this type of micromobility vehicle in urban areas. Thus, there is a need to study e-scooter users’ behaviour and their interaction with cyclists. This research aimed at characterizing the meeting manoeuvre between micromobility users along diverse typologies of two-way bicycle track by using an instrumented e-scooter. As a result, bicycle tracks having concrete or vegetated curb presented lower clearance distance (≈0.8 m) than those without edge elements (>1 m), with no statistically significant differences found between the interaction with bicycles and e-scooters. Additionally, an online questionnaire was proposed to assess users’ perceived risk during the meeting manoeuvre, concluding that micromobility users feel safer and more comfortable riding on pavements away from parked or moving motorized traffic, and on protected bicycle tracks.