Freeway merging behaviour and safety of acceleration lanes: Field study

Appropriate geometry of the entrance terminal allows the vehicles entering into a freeway to merge into the mainline safely and comfortably, without interfering with the through traffic movement. Several aspects of traffic behaviour on speed-change lanes (SCL) and freeway right lane were examined using data from 23 merging sites on Highway 417 in Ottawa (Canada). Analysis of traffic behaviour has shown that the merging speed of entering vehicles is affected by geometrics of the entrance ramp on both upstream and downstream the gore. Lower merging speeds were shown to be associated with higher collisions on the SCL. Right lane traffic volumes and merging speed of entering vehicle were shown to affect the right lane speed along the SCL. Six statistically significant models were developed for the prediction of merging speed, acceleration on the SCL, effective length used for acceleration, freeway right lane speed, and safety performance of the SCL.