Project: Comparison of Turning Circle Requirements

Reference: S0038/VE

Last update: 09/09/2003 13:15:20

Objectives

The project objectives are to:

* demonstrate the difference between the two tests and provide evidence to support the UK view that the gradual test method does not represent the worst case scenario and could, in reality, result in a greater swing out and therefore a greater pedestrian safety hazard;
* consider a compromise proposal which limits outswing for all vehicles to 600mm when measured using the gradual test. This is viewed as a fudge by the UK, who believe that the correct and only repeatable test is the steady state test;
* look at the knock on implications for shorter vehicles 10 to 12m, these are also required to comply with the turning circle requirements; and
* model outswings with 15, 10 and 12 metre vehicles.

The results will form the UK proposal to the commission and aid the decision process to maintain and improve levels of safety.

Description

The project considered the predicted turning circles for three types of Bus/Coach against the requirements in European Community Directive 96/53/EC and UN/ECE Regulation 36.

The vehicles included in this study were:

* 10m midi bus;
* 12m single deck bus; and
* 15m luxury coach.

The prediction was generated using an add-on to AutoCAD called AutoTrack. This program models the steering geometry of traditional designs as well as vehicles having electronically steered rear axles.

Contractor(s)

Parsons Brinckerhoff Limited
4 Roger Street, London, WC1N 2JX
+44 (0)20 7242 2898

Contract details

Cost to the Department: £3,550.00

Actual start date: 18 August 2000

Actual completion date: 31 January 2001

Publication(s)

HHI43044/1/3. Comparison of turning circle requirements
Author: Parsons Brinckerhoff Ltd
Publication date: 01/11/2000
Unpublished
Source: Contact: geoff.harvey@dft.gsi.gov.uk

Summary of results

  1. This project considered the predicted turning circles for three types of Buses/Coaches against the requirements in European Community Directive 96/53/EC and UN/ECE Regulation 36:

    10m Midi Bus
    12m Single Deck Bus
    15m Luxury Coach

    The prediction was generated using an add-on to AutoCAD called AutoTrack. The program can model the steering geometry of traditional designs as well as vehicles that have electronically steered rear axles.

    The model prediction for the coach was found to be slightly different from manufacturer's published data. The model predicted that the coach would pass outside the 5.3m inner radius defined in the regulations, whereas the published data showed it passing within.

    The results of the tests show that for the same vehicle the measured out-turn is considerably less when measured by the UN/ECE Regulation 36 test than when measured by the European Directive 96/53/EC.

    The project continued with an investigation into the effect of wheelbase on the turning circle of the 15m Coach. This indicated that the vehicle out-turn is increased as the wheelbase is decreased.