Curve Advisory Study

Using Connected Vehicle data to understand curve advisory

Curved road segments can be dangerous due to inappropriate driver behaviour and road design. In the case of the Cahill Expressway (which has a speed limit of 60 km/h and a curve advisory speed of 35 km/h when going up the curved ramp), transport professionals wanted to see if the road was being interacted with appropriately with drivers heading north.

Compass’ data showed evidence of high g-forces even if cars were travelling at the appropriate curve advisory speed. There was also evidence of occasional speeding and drivers not following the advisory speed limit. The acceleration/deceleration data showed some cars experienced difficulty driving up the ramp and the swerving data showed heavy swerving, both left and right.

As the two graphs show, there appears to be violent swerving at -0.7g. Particularly on the left hand bend with vehicles travelling between 45-70 km/h well above the posted advisory limit.