The motoring organisation commissioned the ARRB Group to conduct an audit of the road.

The work included identifying significant issues along the route and ways to address them.

One of the areas of concern are the Kiama Bends, which is  congested during holiday periods.

The report suggests the completion of the Princes Highway upgrade immediately south may fix these traffic hold-ups.

‘‘However, the upgrade will not provide any improvement to road safety, and may in fact contribute to an increased risk of crashes through the Kiama Bends section,’’ the audit stated.

‘‘With the completion of upgrades from Gerringong to Nowra, motorists will have driven along over 30 kilometres of high-standard, high-speed motorway conditions interrupted by three kilometres of restricted carriageway that requires a very different driving attitude.’’

The report suggests a bypass is the only ‘‘viable option’’ to address the issue of crashes.

The Riverside Drive exit just north of Kiama is also a concern as a left-hand climbing lane for slow vehicles changes into an exit lane for Bombo.

This creates ‘‘an increase in lane changing and traffic weaving’’ as slow vehicles try to move out of the lane and exiting cars try to move in.

To deal with the problem of head-on crashes along the dual carriageway south of Jervis Bay, the report recommends a divided 2+1 carriageway approach, with a cable barrier separating traffic.

The 2+1 approach would consist of two lanes in one direction and one lane in the other, alternating every few kilometres.

The report also recommends a staged implementation of the Albion Park Rail bypass.

The Princes Highway from Dapto to the Victorian border is ‘‘the Jekyll and Hyde of Australian highways’’, according to an audit of the road by the NRMA.

The organisation commissioned the ARRB Group, which provides research and consulting to the road and transport industry, to undertake an audit of the 228 kilometres of the highway from Dapto to the Victorian border.

The audit compared the crash statistics from 2008-12 as supplied by the NSW Centre for Road Safety with those from the period 2003-2007.

The audit found there was little difference in casualty crashes between the two time periods, but fatalities had fallen by 31per cent, from 64 to 44.

The audit discovered that the most dangerous sections of the highway were the undivided dual carriageways, which make up the bulk of the route from Jervis Bay south.

It stated that 78.4per cent of all casualty crashes occurred on those sections of the highway while the upgraded sections between Albion Park and Kiama had led to reductions in crashes.

That high rate of crashes comes despite substantially lower traffic volumes on undivided roads – an average of 7300 vehicles a day – when compared to 33,000 on the divided sections.

The much higher crash risk on the undivided carriageways compared to those divided sections is what led NRMA South Coast region director Alan Evans to call it a ‘‘Jekyll and Hyde’’ highway.

‘‘The highway north of Jervis Bay Road has seen considerable work done by the NSW and Australian governments,’’ Mr Evans said.

‘‘It is now a safer and more efficient road than before, with casualty rates falling in some parts by almost 90per cent.

‘‘South of Jervis Bay Road, the Princes Highway remains, to a large extent, a death trap.’’

The study breaks the highway into sections and gives each a risk score.

It rates almost 300 kilometres of the highway south of Jervis Bay as ‘‘high risk’’, compared to just 30 kilometres in the northern section.

Mr Evans said the study was cause for concern given the road is so heavily used during the summer holiday period.

‘‘For the sake of those South Coast communities and those families who access the highway during the holidays, let’s hope this report lays down a pathway to finish the upgrade of the Princes Highway once and for all,’’ Mr Evans said.