Impact of Green Arrow Signal on Driver Behaviour and Road Safety in - - PowerPoint PPT Presentation

Faculty of Civil Engineering Chair of Road and Traffic Engineering

Impact of Green Arrow Signal on Driver Behaviour and Road Safety in Poland

Radoslaw Bak, M.Sc Mariusz Kiec, Ph.D Remigiusz Wojtal, Ph.D

ICTCT, Maribor 24-25.10.2013 r.

Cracow University

• f Technology

Overview of presentation

• Introduction
• Idea of Green Arrow Signal (GAS) in Poland
• GAS safety and operation problems in Poland
• Methodology of analyses

– Accident database – Driver’s behaviour study – Conflict analysis

• Results
• Conclusions

Aim of the analyses

• Identification of safety hazard and
• peration problem related to green arrow

signal

• Assessment of possibility of VIVDS

application

Green arrow signal (GAS)

• Allow to turn right (or left) when red signal is

displayed, usually under special conditions (after giving a right of way or/and complete stop)

Poland Czech Republic Spain Belgium Germany

Green Arrow Signal in Poland

TS: Arrow-shaped sign 1st definition of GAS HC: Complete stop before stop bar becomes necessary TS: GAS must be changed to protected mode (non-collision) TS: Restoration of technical standards from before 2003

Since 2009 GAS may operate in: permissive mode protected mode permissive-protected mode Since 2009 GAS may operate in: permissive mode protected mode permissive-protected mode

GAS safety and operation problems

• Changes in law regulations and technical standards

has been done without safety analysis

• Political issue
• Commonly recognized as unsafe, especially for

pedestrians and cyclists

• Low drivers’ propensity to adjust to law regulations

• No reliable accident analysis
• Incomplete accident data (PDO are not thoroughly

underreported)

• Lack of empirical research

GAS safety and operation problems

GAS Conflicts

• vehicle-vehicle:

– Through movement – Left turn – U-turn

• pedestrian
• cyclists
• public transport

Methodology

• Application of three method techniques

used in GAS (RTOR) safety research:

– Accident analysis – Drivers’ behaviour – Traffic conflict technique

Accident analysis

• Accidents with pedestrians and cyclists in Cracow
• n signalized intersections (2 year accident

database) – 152 accidents

• Driver fault/error (109 acc. => 72%)

Entrance crosswalk Crosswalk on exit

Green signal (protected) GAS (permissive) Right turn (permissive) Through (protected) Left turn (permissive)

Left

6 9 8 8 19

Right

7 10 27 9 6

Both

13 (12%) 19 (17%) 35 (32%) 17 (15%) 25 (23%)

Accident analysis

Left turn (permissive mode) Right turn (permissive mode) Crosswalk on exit (protected mode) Crosswalk on entrance (protected mode) Right turn (GAS)

19 19 6 6 8 8 9 9 6 6 7 7 9 9 10 10 27 27 8 8

Accidents with Accidents with cyclists cyclists

Drivers’ behaviour

Green arrow indicated Red only

correct entering no stopping / yield to pedestrians GAS not used Entering red after yellow signal Entering red after GAS Entering red

P1 2,8% 75,4% 2,0% 8,1% 11,7% 19,8% P2 1,6% 74,8% 1,9% 11,3% 10,3% 21,6% P3 1,7% 58,8% 3,4% 23,5% 12,6% 36,1% P4 2,0% 64,6% 2,0% 18,7% 12,7% 31,4% P1 Protected mode P2 Permissive mode / possible v-v conflicts P3 Permissive mode / possible v-v, v-p, v-c conflicts P4 Permissive-protected mode / collision may occur in particular stages

Conflict analysis

• Conflict observations (v-v, v-p, v-c) on high-volume

intersections with GAS-permissive mode in Cracow.

• Multiple measurements with video recording in peak

period on 4 intersections (2 with shared lane for right movement)

Opolska (urban) Meissnera (urban) Półłanki (suburban) Łokietka (suburban)

Conflict analysis

Vehicle–Pedestrian / Cyclist Conflicts

CP1 Sudden vehicle and pedestrian stop CP2 Sudden vehicle stop before crosswalk CP3 Failure to give a right of way to pedestrian – pedestrian is stopped

• n crosswalk

CP4 Failure to give a right of way to pedestrian – pedestrian can not enter crosswalk CP5 Vehicle stops on crosswalk – pedestrians have to come around vehicles CP6 Vehicle goes through pedestrian group

VIVDS conflict analysis

• Video imaging vehicle detection systems

are commonly used for detecting traffic at intersections

• Is there possibility to apply standard

VIVDS technology to estimate GAS safety hazard?

VIVDS Preliminary research

• VIVDS application:

– Detector layout – Detection accurancy – Surrogate safety measures

VIVDS Preliminary research

• VIVDS seem to be difficult to obtain classical SSM

like Time to Collision or Post-Encroachment Time

Conclusions

• Analysis conducted on few intersections in Cracow

indicated problems with GAS: – despite the lack of enough data – Drivers don’t obey

• Drivers have problems with adjusting to law regulations

contributing to the safety issues

Conclusions

• Assessment of safety analysis requires use of traffic

conflicts technique: – due to limited accident database it can be the only method to develop how to operate and design of GAS

• VIVDS has limitations and needs further developments

but it seems effective tool in safety analysis – need for proper calibration of system – need for new SSM

21 21

Thank You !!!

Radoslaw Bak: rbak@pk.edu.pl Mariusz Kiec: mkiec@pk.edu.pl Remigiusz Wojtal: rwojtal@pk.edu.pl