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These results are reinforced by the next finding that angle crashes involving a single heavy
vehicle are more likely (OR=2.283, p=0.001) to occur at intersections than mid-blocks. It

should be noted that our study focussed on single-vehicle crashes. This implies that the
crashes likely involved the side of heavy vehicles hitting pedestrians or fixed objects at

intersections. The latter type of crash would likely involve a heavy vehicle that was making a
tight turn and hitting a fixed object placed near the edge of the road or in the road median. In

addition, due to the limited road space in the Melbourne metropolitan area between public

transport (buses and trams) and private vehicles, heavy-vehicle operators may focus more
attention on public transport (buses and trams) and cyclists in urban Australia cities

(Austroads, 2007).

Interestingly, vehicle overturn was more likely (OR=1.722, p=0.092) to be associated with

single heavy-vehicle crashes at intersections rather than in mid-blocks. This result was in
contrast to Al-Ghamdi’s (2003) finding that vehicle (all vehicles) overturn crashes were more

likely to occur in mid-blocks in urban areas. One possible explanation for the finding may be
that trucks overturn at intersections when making a difficult turn or a turn at excessive speed.

Overturning during a turning movement is more likely to occur to heavy vehicles, partly

because of their higher centre of gravity. Again, with limited road space in urban areas, there
might be insufficient space for heavy vehicles to turn safely, especially at the posted speed

limits, at intersections in Australia (Austroads, 2010).

As shown in Table 3.2, the posted speed limit had a significant influence on crashes
occurring at intersections or mid-blocks. Compared to local roads (with speed limits

<50km/h), single heavy-vehicle crashes on roads with higher speed limits are more likely to

occur in mid-blocks than at intersections. This result was expected, because vehicles driven at
higher speed might be more likely to lose control and run off the road at mid-blocks. This

explanation is supported by the observation that crashes involving heavy vehicles hitting

fixed objects in mid-block had a higher percentage than the corresponding crashes at
intersections, although this variable was not statistically significant in the model.

Furthermore, at speeds above 60km/h, it is more difficult for a heavy vehicle to stop in mid-
block to avoid hitting pedestrians or other non-motorists.

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