http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/1867 2026-05-15T07:49:30Z 2026-05-15T07:49:30Z Malaghan, Vinayak Devendra http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/21325 2026-05-14T12:03:25Z 2021-04-01T00:00:00Z

Modeling acceleration and deceleration rates for two-lane rural highways using global positioning system data Malaghan, Vinayak Devendra Several past studies developed acceleration/deceleration rate models as a function of a single explanatory variable. Most of them were spot speed studies with speeds measured at specific locations on curves (usually midpoint of the curve) and tangents to determine acceleration and deceleration rates. Fewer studies adopted an estimated value of 0.85 m/s2 for both deceleration and acceleration rates while approaching and departing curves, respectively. In this study, instrumented vehicles with a high-end GPS (global positioning system) device were used to collect the continuous speed profile data for two-lane rural highways. The speed profiles were used to locate the speeds at the beginning and end of deceleration/acceleration on the successive road geometric elements to calculate the deceleration/acceleration rate. The influence of different geometric design variables on the acceleration/deceleration rate was analysed to develop regression models. This study also inspeced the assumption of constant operating speed on the horizontal curve. The study results indicated that mean operating speeds measured at the point of curvature (PC) or point of tangency (PT), the midpoint of curve (MC), and the end of deceleration in curve were statistically different. Acceleration/deceleration rates as a function of different geometric variables improved the accuracy of models. This was evident from model validation and comparison with existing models in the literature. The results of this study highlight the significance of using continuous speed profile data to locate the beginning and end of deceleration/acceleration and considering different geometric variables to calibrate acceleration/deceleration rate models.

2021-04-01T00:00:00Z Malaghan, Vinayak Devendra http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/21324 2026-05-14T11:54:32Z 2021-05-01T00:00:00Z

Exploring maximum and minimum operating speed positions on road geometric elements using continuous speed data Malaghan, Vinayak Devendra Speed prediction models are commonly developed using maximum and minimum operating speeds measured at or within specific locations on the tangents and horizontal curves, respectively. However, the actual distribution of the maximum and minimum operating speed positions on the entire lengths of the geometric elements (tangents and curves) have not been rigorously studied and, therefore, present opportunities to refine further and develop robust speed prediction models. This paper presents the probability distributions (normal, lognormal, gamma, and Weibull) for speed positions on the entire tangent and curve lengths using continuous speed data recorded on two-lane rural highways in India. The findings showed that the data could be best approximated for a large number of horizontal curves and tangents using the normal and Weibull distributions. Also, the results showed that the operating speeds measured at the midpoint of the horizontal curves overestimate the actual minimum operating speeds measured over the entire curve length of horizontal curves between 1.2 and 1.9  km/h. Similarly, maximum operating speeds measured at or within a 200-m length from the point of curvature into the approach tangents underestimate the maximum operating speeds measured over the entire length of tangents between 1.33 and 1.77  km/h. The results of this study highlight the importance of considering the entire length of geometric elements in developing accurate speed prediction models for use in evaluating highway design consistency.

2021-05-01T00:00:00Z Malaghan, Vinayak Devendra http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/21323 2026-05-14T10:54:16Z 2020-08-01T00:00:00Z

Speed prediction models for heavy passenger vehicles on rural highways based on an instrumented vehicle study Malaghan, Vinayak Devendra This study developed operating speed prediction models on tangents, curves, and tangent-to-curve transitions for heavy passenger vehicles (HPVs), using continuous speed profiles. Continuous speed profile data for HPVs were collected on two-lane rural highway sections, spanning a total length of 77 km. The curve radius, degree of curve, and preceding tangent length were found to be the influencing variables in predicting both the operating speed on the horizontal curves and the operating speed differential from tangent-to-curve transitions. The study also modeled the relationship between the differential of the 85th percentile operating speed (Δ⁢𝑉85) and 85th percentile operating speed differential (Δ85⁢𝑉). The analysis results from empirical data revealed that Δ⁢𝑉85 underestimates Δ85⁢𝑉 by 5.01 km/h. The reliability of the developed models was validated and compared with existing models from literature. The study highlights the significance of using continuous speed profile data to calibrate the operating speed models.

2020-08-01T00:00:00Z Malaghan, Vinayak Devendra http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/21322 2026-05-14T10:49:39Z 2022-05-01T00:00:00Z

A short-term naturalistic driving study on predicting comfort thresholds for horizontal curves on two-lane rural highways Malaghan, Vinayak Devendra The comfort threshold is one of the basic controls in designing horizontal alignment. Some studies have implied that the recommended comfort thresholds are conservative because they were determined using the traditional approach for vehicle design and corresponding driver behavior during the 1930s and 1940s. Drivers exceed the recommended comfort thresholds (because they are conservative) when traversing horizontal curves, which results in overturning and lateral skidding of the vehicle, increasing the chances of crashes on the horizontal curves. Therefore, the design guidelines need to consider comfort thresholds determined using recent approaches in data collection for modern vehicle design and corresponding driver behavior. Limited studies have determined the comfort thresholds for horizontal curves. Specifically, no studies determined the comfort thresholds for the horizontal alignment design in India. Thus, this study attempted to estimate the comfort thresholds for horizontal curves using an advanced Global Positioning System (GPS) device instrumented in passenger cars for data collection on two-lane rural highways in India. An all-subset regression approach was used to model comfort thresholds, and statistics such as Akaike information criterion (AIC), coefficient of determination, and cross-validation were used in the model selection. The study results showed no significant difference in the comfort thresholds on the right-turn and left-turn curves. Among the various geometric design features of curves, the curve radius significantly influenced the variation in the comfort threshold. The estimated comfort thresholds were higher than the side-friction demand recommended in an Indian design guideline. This study highlights the importance of determining the comfort thresholds using an advanced data collection tool for modern vehicle design and corresponding driver behavior to avoid crashes on the horizontal curves.

2022-05-01T00:00:00Z