Transurban Group's (ASX:TCL) August traffic has continued to grow, although the pace slowed from June and July, with weakness in Melbourne traffic of concern, Jefferies said in a Thursday note.

North America, which accounts for less than 10% of the group's earnings, is performing ahead of expectations and is likely to remain within management's fiscal 2027 expectations, the investment firm said.

Transurban's fiscal 2027 distribution guidance of AU$0.72 per share assumes traffic trends remain broadly in line with June and July growth rates, so August's average daily traffic growth of 1.9% remains consistent with that guidance, Jefferies said.

However, rising fuel prices, which are expected to begin affecting motorists from September, increase the risk of near-term traffic softness.

Jefferies maintained its hold rating on Transurban with a price target of AU$13.11 per share.