Risk Assessment

A risk assessment analysis was carried out for each of the items listed under Section 5.2 and Table 5-1 which follows, as required and in accordance with the SARSA Manual. The steps set out in the Manual are as follows:

Step 1: Estimate the Possible Crash Frequency

Each of the listed items was assessed in terms of the frequency of crashes at each location, based on a “do nothing” approach. The table below defines the frequency of events.

Table 4-2: Possible Crash Frequency

FREQUENCY	DEFINITION
Frequent	One or more per month
Probable	One or more per year (but less than one a month)
Occasional	Once every one to three years
Remote	Less frequent than once in three years

Step 2: Estimate the Possible Crash Severity

Following the frequency of each event, the severity of those crashes was assessed using the severity indicators as set out in the table below:

Table 4-3: Possible Crash Severity

SEVERITY or OUTCOME	EQUIVALENT CRASH OUTCOME	EXAMPLES
Catastrophic	Likely multiple deaths	High Speed Vehicle crash on Freeway Car runs into crowded bus stop Bus and petrol tanker collide
Serious	Likely death or serious injury requiring hospitalisation	High or medium speed vehicle / vehicle crash High or medium speed collision with fixed roadside object Pedestrian or cyclist struck by car
Minor	Likely minor injury	Low speed vehicle crash Cyclist falling from bicycle Left-turn rear end crash in a slip lane
Negligible	Likely trivial injury or property damage only	Some low speed vehicle crashes Pedestrian walks into object Car reverses into post

Step 3: Determine the level of Risk

Based on the outcomes of Steps 1 & 2 above, level of risk was determined in the Matrix shown in the table below:

Table 4-4: Level of Risk

		FREQUENCY
		Frequent	Probable	Occasional	Remote
SEVERITY	Catastrophic	Intolerable	High	High	Medium
	Serious	High	High	Medium	Medium
	Minor	High	Medium	Medium	Low
	Negligible	Medium	Medium	Low	Low

Step 4: Determine a Course of Action

The course of action for each of the Items was then determined from Table 4-5:

Table 4-5: Course of Action

RISK	SUGGESTED TREATMENT ACTION
Intolerable	The safety concern “must” be corrected, even if the cost is high.
High	The safety concern “should” be corrected or the risk significantly reduced, even if the treatment cost is high
Medium	The safety concern “should” be corrected or the risk significantly reduced, if the treatment cost is moderate, but not necessarily high
Low	The safety concern “should” be corrected or the risk reduced if the treatment cost is low.