Project: 'A' Pillar Obscuration. An On The Spot Study to Quantify the Problem

Reference: S0414/V8

Last update: 09/08/2006 15:05:21

Objectives

The objective of this project is to identify for the Department whether modern car design can obscure the road and other road users to such an extent that it is an important contributory factor in road accidents. The focus of this project is on interrogation of the On The Spot (OTS) accident database to determine any potential link between 'A' pillar design and crash causation. Any identified sub-set of cases where 'A' pillar design could have been a factor should have their causative influence evaluated.

In particular there is a need to:

. identify within the OTS accident database cases where the 'A' pillar design could have been a contributory factor;
. indicate the extent to which 'A' pillar obscuration may have been a causative factor in real world accidents;
. provide information on what drivers see in real world accidents and how their field of vision is affected by car design, especially 'A' pillar design;
. make recommendations on the degree to which action may be taken to minimise any risks associated with modern 'A' pillar design and the direction and need for further work; and
. prepare an initial Regulatory Impact Assessment setting out the options for and against action on 'A' pillar design and field of vision.

Description

Driver vision is an important factor in the provision of a safe transport system, but there is evidence that car design in relation to the windscreen, forward roof supports and front door frames has changed significantly over recent years. The main concern, which has been made raised by the Parliamentary Advisory Council for Transport Safety (PACTS) and others, is that the thickness of the 'A' pillars - essentially the forward roof supports - have been increasing. It is argued that this is a causation factor in accidents due to the obscuration from the 'A' pillars limiting the drivers' field of vision. There is some ad-hoc evidence to support this claim, but to date the effects of 'A' pillar obscuration have not been thoroughly investigated. Hence, it is important to test the hypothesis that modern car design can obscure the road and other road users to such an extent that it is an important contributory factor in accidents.

This project will provide information on what drivers see in real world accidents and how their field of vision is affected by car design. The research will identify in the On The Spot (OTS) accident database where the 'A' pillar could be a contributory factor and indicate the extent to which 'A' pillar obscuration may have been a causative factor. The work will help determine whether their concerns are valid and if further more substantive work is required to properly quantify the problem. The work will also determine the action that may be taken to minimise any risks associated with modern 'A' pillar design.

Contractor(s)

TRL Limited
Crowthorne House, Nine Mile Ride, Wokingham, Berkshire, RG40 3GA
+44 (0)1344 773131

Contract details

Cost to the Department: £77,050.00

Actual start date: 01 November 2004

Actual completion date: 09 August 2006

Publication(s)

PPR159. Investigation Into 'A' Pillar Obscuration - A Study to Quantify the Problem Using Real World Data
Author: TRL Limited
Publication date: 09/08/2006
Published
Source: Contact brian.greenway@dft.gsi.gov.uk
More information: http://www.trl.co.uk/store/report_search.asp?pid=108

Summary of results

  1. This study was based on real life accident data collected from current OTS accident studies. Those accidents which matched the strict selection criteria were reconstructed using computer generated video clips showing scaled road and vehicle details, along with the 'A' pillar sight obscuration area matched to both the vehicle and driver in monocular vision to give a 'worst possible scenario' of the drivers field of vision. This allowed detailed analysis of the accident to show whether 'A' pillar obscuration may have been a causative factor. The findings are that, whilst 'A' pillar obscuration can occur, there is rarely only one factor that contributes to an accident and at this stage there is not enough evidence to suggest that changes to the current legislation regarding 'A' pillar design would be of benefit.