Page 39 - Proceeding of Atrans Young Researcher's Forum 2019_Neat

“Transportation for A Better Life:
Smart Mobility for Now and Then”

23 August 2019, Bangkok, Thailand

Indecision zone and factors influence the stop/go decision at the yellow traffic
signal: the comparison of motorcyclists with passenger car’s driver
Identification number: AYRF2019-005
2
1
3
Siwa BUAHOME , Wichuda SATIENNAM , Thaned SATIENNAM

1 Department of Civil Engineering, Faculty of Engineering
Khon Kaen University
Telephone 043-261457, Fax. 043-261457
E-mail: martsiwabuahom@gmail.com

2,3 Department of Civil Engineering, Faculty of Engineering
Khon Kaen University
Telephone 043-261457, Fax. 043-261457
E-mail: wichsa@kku.ac.th
E-mail: sthaned@kku.ac.th

Abstract
The yellow light traffic signal is a decisive period for a driver to stop or go. Current knowledge of
driver behavior and influential factors in the mixed traffic road conditions are limited. This study reveals and
compares the indecision zone and factors influencing the stop/go decision of the car driver and the
motorcyclists. An urban mixed traffic high-speed intersection is selected to install the video cameras to record
driver behaviors. Descriptive statistics and binary logistic regression are conducted. The results revealed that
a vehicle type, distance from stopping line, approaching speed and adjacent vehicle are influenced to the
driver's stop/go decision at the yellow light. The passenger car driver tends to follow their heading car to go
through the intersection or tend to stop when the car in the adjacent lane stop. The decision to go of the
motorcyclist is dominated by the passenger car. For the dilemma zone type II, this study found that the
indecision zone of the passenger car driver is smaller and nearer to the intersection than those of the
motorcyclists. Based on the findings, the high-risk of the motorcyclists running in mixed traffic and safety
countermeasures are discussed.
Keywords: Stop/go, Yellow traffic signal, Motorcyclist, Indecision zone, Mixed traffic

1. Introduction
Traffic signal control timely separates intersection
flow to avoid crashes. The yellow light is a transitional the stop/go decision of the car driver and the motorcyclists.
period that plays an important role for intersection safety.
The yellow light reminds drivers at the end of the green Table 1 factor influencing stop/go decision.
light to safely go through an intersection or timely and Studies findings
safety stop at the intersection before the red light appears. Pathivada and Distance from the stop line, vehicle’s
This decision is very important and influenced by many Perumal approach speed and type of intersection
(2019)
were found to be important factors in drivers
factors. Crashes from wrong decision are severe especially stop/go decisions. Vehicle type, which is a
for the motorcyclist that running mixed in the high-speed characteristic of mixed traffic conditions is
traffic. found to have a significant impact on the
From the literature reviews, drivers’ stop/go driver’s decision at the onset of yellow.
decisions and their influencing factors are as shown in Bao et al. - Intersections without monitoring devices
widen the indecision zone.
(2018)
Table 1. Obviously, current knowledge of driver behavior - Drivers’ decision making at the onset of
and influential factors are available for the developed the yellow indication is greatly influenced
counties’ road. The information for the mixed traffic road by the vehicle’s spot speed, the distance
conditions, as in Thai’s road, are limited. This study, to the stop line, and signal and monitoring
devices.
therefore, aims to reveal and compare the indecision zone - The presence of an adjacent vehicle with
and factors influencing a short space headway can particularly
motivate the following driver to make a

14