Traffic conflict technique in the Czech Republic Ji Ambros - - PDF document

Traffic conflict technique in the Czech Republic

Jiří Ambros Centrum dopravního výzkumu, v.v.i. (Transport Research Centre) Czech Republic

24th ICTCT workshop

Presentation

1) Introduction of TCT 2) History of TCT in the Czech Republic 3) Findings of literature survey 4) Pilot TCT observations 5) Lessons learned

Introduction of TCT (1/2)

• tradition of using accident analyses for

road safety assessment

• drawbacks: regression to mean, quality of

data, underreporting… ex post!

• alternative approach: safety performance

indicators including traffic conflicts (TCT)

• TCT gives more data… ex ante!

Introduction of TCT (2/2)

• many TCTs around the world, general

mutual agreement

• TCT has to be reliable and valid
• reliability ← training
• validity ← correlation with accidents
• they show the quality of TCT

Czech TCTs

• usually known only at universities
• Prague: manual observations
• Ostrava: from video
• both subjective
• not tested
• CDV in Brno

Prague Ostrava Brno

Literature survey (1/2)

• focused on developing universal practical

TCT method

• TCT complements accident analyses
• various opinions on validity / way to

„market the procedure“

• progress to semiautomatic methods or

video detection

• do not develop but choose from existing
• nes

Literature survey (2/2)

• survey findings show the way for Czech

TCT:

a) follow existing valid TCT method or b) use Czech method which has to be validated

• need to study reliability and validity of both

existing Czech TCT approaches

• calibration by comparing their results
• two pilots up to now…

Pilot observations (1/3)

1) Brno: busy signalized intersection, mixed traffic (cars, public transport, pedestrians, cyclists)

• 1 peak hour
• two teams
• manual vs video

Pilot observations (2/3)

Conflict records were different – due to insufficient training before the observation?

• mostly slight ones
• severe conflicts were always recorded
• safety diagnoses were generally the same

Pilot observations (3/3)

2) Ostrava: non-signalized intersection, busy traffic, incl. tramway and students

• 16 students, 3x 2-hour observations
• repeated training by lecture
• results were incomparable
• some students improved
• some lacked the motivation

Lessons learned

• pilot observations show the need of

training → reliability

• lecture + testing observation + video e-

learning for all target groups

• then proceed to further observations
• the aim is to produce common TCT

guidelines for practical use

Thank you for your attention

Jiří Ambros Centrum dopravního výzkumu, v.v.i. (Transport Research Centre) Czech Republic

24th ICTCT workshop