Table of Contents

5.1.3 Incident Types and Characteristics

It is useful to classify incidents according to their severity and potential duration as this greatly assists in a consistent, appropriate and timely response. A typical classification system that can be used is outlined in Table 5.1.

Table 5.1: Typical incident types/classifications

 Level 1Level 2 Level 3 Level 4 Level 5
Type of incidentVehicle on shoulderVehicle in lane

Minor crash (no injury)

Minor debris

Serious crash (injury?)

Debris

Fire

Major injury crash

Hazmat

Fire

Estimated durationNil0–30 mins30–60 mins1–2 h> 2 h
Typical response

Traffic Response Unit (TRU)/tow

TRUs are roaming on-road services that provide basic breakdown assistance, incident clearance and traffic control

TRU/tow

Traffic control

Police

Traffic control

Tow

Clean-up

Police

Fire

Medical

Traffic control

Tow

Clean-up

Police

Fire

Medical

Hazmat

Traffic control

Tow

Clean-up

Source: Austroads (2007a).

The approximate occurrence pattern of traffic incidents, based on US data, can be seen in Figure 5.1 (Cambridge Systematics 1997).

Figure 5.1: Occurrence of incidents by type

Note: vhd: vehicle-hour delay per day in peak period.

Source: Cambridge Systematics (1997).