Abstract
With rapid urbanization, traffic congestion has become a severe problem in Indian cities with people
spending a majority of their time stuck in traffic. While there are many reasons contributing to it - like
bad road infrastructure, poor traffic management and heterogeneous traffic, a significant cause is identified as irrational driver behavior. These behaviors are mainly caused by various environmental factors
like noise (both ambient and persistent honking), pedestrians, heterogeneous traffic, other vehicles not
following rules, bad roads etc. The objective of the current study is to examine in particular two independent but conceptually linked external or environmental factors of honking and lane system on driver
behavior. Of particular interest is the correlations between physiological changes, psychological states
like anxiety/stress/frustration and decisions. A hypothesis based on observation and understanding of
Indian roads, is that honking at high decibels though normalised and adapted by Indian road users is
reflected on behavioral responses in addition to long term health effects. While there have been many
studies addressing traffic congestion due to external factors, few cover driver behaviours caused due
to these factors. In this study, we delve deeper into changes in driver behaviour due to one external
attribute - that of persistent honking by a trailing vehicle.
There have been studies on the effects of honking and most of them report better traffic flow because
of honking. That is, honking is considered as an inter-vehicle or vehicle to pedestrian communication.
The studies do not take into account changes in the driver behaviour due to honking - both honks of
acoustic properties approved by certifying agencies and especially from non-standard honks as heard
in traffic conditions in India where the current experiment was conducted. Honking, designed to be
a tool for the drivers to communicate effectively and also to alert other road users, is often used on
Indian roads as a mechanism to express frustration either due to traffic jams, a purely reflex action, a
sense of entitlement (as a function of the cost/power of the vehicle) to the road and right of way etc.,
rather than to ensure safe driving. To analyse this effect, we looked at driver behaviour and his/her
physiological measurements in the honking environment. These factors are inter-linked, as lane system
in heterogeneous traffic leads to honking as traffic flow enabler or as aggression towards a smaller slow
moving vehicle.
As the first step, the validity of virtual simulators (with head mounted display and tactile controls)
to present immersive experience and near real-life traffic conditions was tested. Hence, to study two
environmental or external effects on driver behavior, the concept of lane adherence and honking was
considered. We have chosen to simulate the real world rather than conduct a real-world experiment
for two main reasons- 1. In real world traffic, we cannot ensure experimental control of honkingthat is, present the same or similar situations during the data collection time. Second, variation in the
honking environment for each person creates inconsistencies in experiences and the data. To focus
on the decision making aspect in driver behaviour, we need to ensure a similar environment to all
participants. 2. It is difficult to impose traffic control in the real world. Creation of a controlled traffic
environment multiple times, where different vehicles are moving synchronously, is difficult logistically
and expensive. Thus, we solve this problem by using a Virtual environment, which can be controlled,
manipulated and replicated as many times as needed. It provides a 360 degree 3D environment enabling
different events like decision making and physiological data to be recorded synchronously.
In the experiment for the lane system (experiment done with 30 participants), three scenarios were
presented with the constant condition of the participant vehicle in the middle lane trailing a slow moving
three-wheeler (autorickshaw). The time to reach the finish point, the decision to change lanes and errors
in judgment were recorded. The results indicate that in heterogeneous traffic, roads with no lane marking
allowed the driver to shift and overtake the slow vehicle while strict lane by barricades lead to high levels
of irritation as per the self-report. The feedback on the simulator developed for this study was used as a
basis for the Indian road scenario used in the second study.
In the second study (experiment done with 45 participants) on the physiological and behavioral
changes due to honking on the driver, pulse rate/ skin conductance and driving behavioral choices in
the presented scenarios was recorded. We collected skin conductance/GSR values, as previous studies
have shown that subjective high decibel noise affects the sympathetic nervous system (part of autonomic
ne
