Harikrishna Gaddam

• PhD- Transportation Engineering
• Professor (Assistant) at Gati Shakti Vishwavidyalaya

An outbreak of pandemic disease is a very uncertain event that can occur and spread around the globe within a few days, just because of the fast and dynamic transportation network. There is a significant need to provide support and assistance to small urban and rural public transportation providers on the necessary procedures that should be impleme...

Assessing level of service offered by a railway station to passengers is a tedious job and hence it is essential to have a well-defined framework. This study emphasises on calculating the passenger level of service (P-LOS) of a railway station using point-based system which takes qualitative and quantitative factors into account. With the proposed...

.The present study aims to calibrate a novel multi-class non-lane-based continuum traffic flow model by applying advanced global search optimization algorithms such as Hybrid Search (Combination of genetic algorithm and Nelder Mead) and Generalized Pattern Search. To represent vehicular behavior in non-lane-based mixed traffic environment, the new...

Passenger car equivalency (PCE) values provide a basis for estimating capacity of roadway and its elements such as signalized and unsignalized intersections. The present study aims to provide a novel framework to estimate dynamic PCE values for various vehicle classes under mixed traffic conditions for roundabouts. The data was collected and analyz...

This research study provides a new framework to optimize pedestrian simulation parameters required to replicate emergency evacuation conditions specifically observed in high rise buildings, passenger vehicles and transport terminals. The simulation experiments are performed with generalised social force model in VISWALK simulation environment. The...

The epidemic novel coronavirus disease 2019, abbreviated as COVID-19, has changed people’s mobility choices significantly, which has had a great impact on public transportation because of the public’s risk perception. The pandemic forced many people to shift toward private transport modes, which resulted in a decrease in public transport ridership...

The present study mainly focuses on estimating driver’s gap acceptance parameters such as critical gap and follow-up headways. In addition, meta-analysis was also carried out to compare critical gap values for different vehicle classes obtained from various studies in India. The data were collected and analysed for three different roundabouts locat...

Evacuation characteristics of pedestrians can be captured under two different conditions - one in immediate and another in non-immediate. The safe and quick evacuation of pedestrians from a building in any situation depends on pedestrian and building characteristics. Understanding the behaviour of pedestrians in emergency situations such as earthqu...

The objective of this study is to model the complex behavior of non-lane based heterogeneous traffic which is predominantly occupied by vehicles with varying physical and dynamical characteristics and their staggered car following behavior. This study proposes a new continuum model by considering the properties of two-sided lateral gap in a non-lan...

The present study aims to understand the interaction between different vehicle classes using various vehicle attributes and thereby obtain useful parameters for modelling traffic flow under non-lane based heterogeneous traffic conditions. To achieve this, a separate coordinate system has been developed to extract relevant data from vehicle trajecto...

The aim of this study is to capture the behaviour of non-lane based heterogeneous traffic flow which is predominantly occupied by vehicles with varying physical and dynamical characteristics and their staggered car following behaviour. In order to describe this behaviour, the study presents the higher-order heterogeneous continuum model considering...

This study proposes a new nonlane-based continuum model derived from a two-sided lateral gap-following theory using the relation between microscopic and macroscopic variables. The model considers the effect of lateral gaps of the leading vehicles available on both sides of the following vehicle in multilane scenario. Linear stability analysis is pe...

Modelling non-lane based heterogeneous traffic is difficult compared to lane based heterogeneous traffic as the vehicles do not follow lane discipline and always deviates from its centreline positions. The typical behaviour of vehicles in non-lane based environment can be best explained by staggered vehicle movement, lane sharing, varying physical...

This study is an attempt to establish a suitable speed–density functional relationship for heterogeneous traffic on urban arterials. The model must reproduce the traffic behaviour on traffic stream and satisfy all static and dynamic properties of speed–flow–density relationships. As a first attempt for Indian traffic condition, two behavioural para...

In the original publication, the unit of variable kj in Tables 4 and 7 has been incorrectly published as km/h. The correct unit of variable kj should be veh/h.

The present study aims to calibrate non-lane based macroscopic continuum model by applying different global search optimization techniques such as Genetic Algorithm (GA), Hybrid Search (HS-Combination of GA and Trust region reflective algorithm), Simulated Annealing (SA) and Pattern Search (PS). To represent the non-lane behaviour of vehicles, a ne...

Empirical data is the basis for development and validation of traffic flow models. From the videographic data collected on two urban arterial sections, the temporal evolution of macroscopic variables such as speed, flow and density have been established. Speed data has been obtained to determine the class specific behaviour with respect to varying...

The aim of this study is to capture the behaviour of non-lane based heterogeneous traffic flow which predominantly occupied by vehicles with varying physical and dynamical characteristics and their staggered car following behaviour. In order to describe this behaviour, the study presents the higher order heterogeneous continuum model considering th...

Availability of traffic data is essential for effective design, operation and management of the transportation systems. Obtaining the data using traditional traffic data collection methods for heterogeneous traffic is cumbersome, inaccurate and obsolete. In addition, difficulty is involved in using these methods for continuous monitoring and collec...

First order macroscopic model like Lighthill-Whitham-Richards (LWR) has been extensively studied and applied for various homogeneous traffic problems. Applicability and adaptability of LWR models to various heterogeneous traffic conditions is still under exploration. Finding solutions for the macroscopic models using analytical methods is a complic...

First order macroscopic model like Lighthill-Whitham-Richards (LWR) has been extensively studied and applied for various homogeneous traffic problems. Applicability and adaptability of LWR models to various heterogeneous traffic conditions is still under exploration. Finding solutions for the macroscopic models using analytical methods is a complic...

In heterogeneous traffic conditions, roundabout capacity is described by vehicle and driver characteristics which are different from traffic conditions in homogeneous conditions. In the present study, the capacity of the roundabout is determined using various capacity formulas such as gap acceptance models given by Highway Capacity Manual 2010 (US)...